| Author |
Thread: Tube Talk |
    
Gold Member Username: Rick_b
Orlando,
FL
Post Number: 1440
Registered: Dec-03
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| Posted on Sunday, January 13, 2008 - 11:05 am: |
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My wife tells me you are never too old....... You have to love an eternal optimist JV.
I'm having a lot of fun fumbling around the fretboard. Try it in between painting. |
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Gold Member Username: Nuck
Post Number: 9583
Registered: Dec-04
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| Posted on Sunday, January 13, 2008 - 11:47 am: |
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Knowing the respondant, I pretty much begged for sarcasm there, eh?
What are you playing, Rick? |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 12044
Registered: May-04
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| Posted on Sunday, January 13, 2008 - 12:41 pm: |
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26 & 27
http://www.poordavidspub.com/#upcoming%20shows |
Gold Member Username: Mike3
Wylie,
Tx
USA
Post Number: 1027
Registered: May-06
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| Posted on Sunday, January 13, 2008 - 03:46 pm: |
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Nuck, about one mile south of my office, no turns.
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Gold Member Username: Nuck
Post Number: 9591
Registered: Dec-04
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| Posted on Sunday, January 13, 2008 - 03:53 pm: |
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Lemme see where I end up that week. |
Gold Member Username: Rick_b
Orlando,
FL
Post Number: 1441
Registered: Dec-03
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| Posted on Sunday, January 13, 2008 - 04:49 pm: |
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Nuck, A '72 and a '79 LP Standard. |
New member Username: Glowaudio
Post Number: 1
Registered: Jan-08
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| Posted on Friday, January 18, 2008 - 01:50 am: |
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Hello all.... we have introduced a new single ended EL84 based tube amp, the GLOW Amp One. Featuring point to point wiring, hand wound transformers, and a USB portal for direct connection to your computer via 16 bit DAC.
Please check us out at www.glow-audio.com
If you have any questions, contact us at: info@glow-audio.com
Cheers! |
Gold Member Username: Artk
Albany,
Oregon
USA
Post Number: 5979
Registered: Feb-05
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| Posted on Friday, January 18, 2008 - 02:35 am: |
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Send me one gratis Jay and I'll tell ya if I like it. |
Gold Member Username: Nuck
Post Number: 9610
Registered: Dec-04
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| Posted on Friday, January 18, 2008 - 06:52 am: |
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Maybe Jay should release one to be circulated between members and reviewed, just like Tim did with his speakers. Whadda ya say Jay? |
Silver Member Username: Stryvn
Post Number: 632
Registered: Dec-06
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| Posted on Friday, January 18, 2008 - 09:04 am: |
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Count me in. I'll start building the Ziggies right away. |
New member Username: Glowaudio
Post Number: 2
Registered: Jan-08
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| Posted on Friday, January 18, 2008 - 01:27 pm: |
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I'd love to give them away, because I truly believe that a small SE amp like our GLOW Amp One can be so much more enjoyable to listen to than the mass market transistor stuff. You can listen to it all day, and never get that "listening fatigue" so characteristic of solid state amps.
Alas, without the money we receive for selling the amps we can't expand our product line. We priced this amp as low as we could ($480) in order to make it affordable.... we are committed to providing affordable but quality gear, so look for more GLOW stuff before long. Don't hesitate to contact us if you have any questions at info@glow-audio.com and check out the news articles about us at 6moons and whathifi.
Cheers.
J.
www.glow-audio.com
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Gold Member Username: Nuck
Post Number: 9616
Registered: Dec-04
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| Posted on Friday, January 18, 2008 - 06:58 pm: |
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Jay, a speaker maker from here sent a small pair around the country to be tested and reviewed. Perhaps one of your amps could do the same, to owners of tube amps here. |
Gold Member Username: Nuck
Post Number: 9617
Registered: Dec-04
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| Posted on Friday, January 18, 2008 - 06:58 pm: |
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http://www.gibson.com/en-us/Lifestyle/Features/Gibson%20Tone%20Tips_%20Tips%20Fo r%20Hap/ |
New member Username: Glowaudio
Post Number: 3
Registered: Jan-08
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| Posted on Sunday, January 20, 2008 - 01:43 pm: |
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Dear All:
It is an interesting offer, and we are flattered. Right now, we have only 5 "demo" amps, and they have all been sent out to various reviewers, 3 of whom are overseas and one in Canada. Co-Founder Mark Mainwaring is responsible for this aspect of the operation, I will discuss your offer with him and try to get you in the queue.
As far as logistics, how does this work... who gets it first, who is in the "chain" of recipients, etc. ????
Seems that there is more initial interest outside the US of A... not surprising, but one of the things we hope to achieve is getting more mainstream recognition of small power tube amplifiers stateside. We hope the Amp One helps to get the word out that a 200 watt per channel transistor amp is not the ONLY option nor the BEST option for HIFI on a budget.
In the meantime, if you would like to see what the growing GLOW community is saying about the Amp One, see: www.glow-audio.com/glowcommunity.html
Finally, keep in mind that we have a 30 day satisfaction guarantee, so if any of you want to take the plunge, there really is no risk.
Beats those Ebay offers from obscure amp suppliers in HK and china, where you have to shell out $150 for shipping and when there is a problem (like when you find it is only 220 V non-switchable) YOU have to pay shipping back to HK!
Regards,
Jay Patrick
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Silver Member Username: Wattsssup
Barrie,
ON
Canada
Post Number: 194
Registered: Aug-06
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| Posted on Sunday, January 20, 2008 - 06:56 pm: |
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"As far as logistics, how does this work... who gets it first, who is in the "chain" of recipients, etc. ????"
It's easy, I get it first, than I send it to the next guy in Ontario, it makes its rounds in Ontario (there are a few of us here), we'll get the Canadian marketing started, than we ship it down to NY, there are a few guys there who have the ability to properly review audiophilia, they send it down to Texas to satisfy a couple of regulars there, than off to Oregon for whirl, and if there's time, maybe a trip to the Outback in Australia.
Perfect. |
Silver Member Username: Wattsssup
Barrie,
ON
Canada
Post Number: 195
Registered: Aug-06
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| Posted on Sunday, January 20, 2008 - 07:00 pm: |
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I should say, I get it first since I'm in the market for a Headphone amp, and this one just might fit the bill. |
Bronze Member Username: Jazzman71
Phoenix,
AZ
USA
Post Number: 53
Registered: Dec-07
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| Posted on Saturday, March 08, 2008 - 12:43 am: |
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I am sure this ground has been plowed on here before, so I apologize in advance, but hey nobody has posted for nearly two months, so WTH. What is the feeling on the benefits, if any, of tube dampers? I know, it depends....
But in any event I am interested in thoughts, as well as whether starting with the source is the most likely location to see if there is any noticeable difference. |
Gold Member Username: Artk
Albany,
Oregon
USA
Post Number: 6487
Registered: Feb-05
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| Posted on Saturday, March 08, 2008 - 10:29 am: |
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I tried several tube dampers when I owned a tube amp and didn't like the results. They made an audible difference but it was not one I liked. I felt that they contributed to a hard edge with the sound that I found unacceptable. It's my bet that that is not the case with all amps and dampers. I hear great things about Herbie's. |
Bronze Member Username: Jazzman71
Phoenix,
AZ
USA
Post Number: 56
Registered: Dec-07
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| Posted on Saturday, March 08, 2008 - 11:21 am: |
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I have Herbie's on a phono stage I recently purchased, so I'll try them on and off before buying any more. |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 12344
Registered: May-04
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| Posted on Saturday, March 08, 2008 - 12:27 pm: |
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This topic has been covered a few times on the forum. Dampers are going to benefit some tubes in some circuits and they won't do anything or won't do anything beneficial in other cases. Before you spend big money on fancy aftermarket audio dampers, buy some high temperature O-rings from anyone selling gaskets. They will be abour 1/4 the cost of audio aftermarket dampers and are essentially the same product. Do not place dampers on output tubes or most driver/input tubes in a power amplifier. If the tube socket is exposed, try a damper on the socket before you place any on the tube itself.
. |
Bronze Member Username: Jazzman71
Phoenix,
AZ
USA
Post Number: 58
Registered: Dec-07
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| Posted on Saturday, March 08, 2008 - 12:54 pm: |
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Thanks Art and Jan.
I have seen the high temp o-rings mentioned. I will keep the dampers off the power amp tubes altogether as you suggest Jan, and try them on and off the phono stage since I already have them. Other than that, I'm probably trying to solve a problem I don't have--never a good idea. |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 12346
Registered: May-04
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| Posted on Saturday, March 08, 2008 - 05:00 pm: |
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You can probably do better by isolating the entire unit. If you aren't certain whether there's a problem, start with the cheapest, most effective solution for the money spent. For me that's either a bag of squash balls under my pre amp and CD player or a 4-5 squash balls suspended on neopreme pipe caps under my turntable and amplifier. I prefer squash balls to tennis balls but you can buy a bag of either at Target, WallMart or any sporting goods store. The nylon drawstring bag keeps the balls together so the equipment doesn't roll around and you only need to lay the bag o'balls in a single layer under the equipment and give a listen. The single balls under my amps and turntable are sitting on neopreme pipe caps from the plumbing department of any home improvement store. They work a bit like the RollerBall isolation devices except they are quite flexible by comparison to the RollerBall's metal to metal contacts. I buy 1 1/2"/2" caps for each squash ball and buy sufficient numbers for the weight and damping required.
If you keep the mechanical vibration away from the equipment, you'll probably not need tube dampers. However, microphonics are an issue with all tubes and some tubes are simply more prone to air-borne feedback than others. Some equipment benefits from sitting directly on the balls and some (my CD player) work best when the balls are under another supporting surface for the equipment (several layers of MDF with damping between each layer) which allows transformer vibration to be sunk into a dense, massive base. Experiment, it will only cost a few dollars compared to the audio aftermarket devices. I've outfitted my entire system for under $50. If you find success with the cheap stuff, then you have a base for comparison when you try the expensive stuff. I find a differnce in results when using either tennis balls to squash balls and prefer the smaller of the two. I think you'll find a noticeable improvement in SQ even if you don't think you have a microphonics problem.
. |
Gold Member Username: Mike3
Wylie,
Tx
USA
Post Number: 1160
Registered: May-06
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| Posted on Saturday, March 08, 2008 - 05:19 pm: |
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Great, now I have to go out and buy squash balls to see what if any difference there is and if I like them or the tennis balls better.
In addition to what Jan posted above, weighting down the equipment may also reap benefits. Per Jan's recommendation I have 4 lead diver weights (3 lbs. each) on my pre-amp. They sit on 2" by 1/2" by 3/4" (approximately) wooden Jenga tiles. This has helped immensely with the harmnonics, more than even the O rings on the phono stage tubes. I tried weights on the CD player and it was not happy. I cannot put weights on the Linn TT due to its suspension. I have not messed with my tuner yet. (Somehow I see it getting tennis balls or squash balls, whatever the CD player liked less.) |
Bronze Member Username: Jazzman71
Phoenix,
AZ
USA
Post Number: 63
Registered: Dec-07
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| Posted on Saturday, March 08, 2008 - 06:02 pm: |
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Thanks Jan. I have heard squash balls mentioned before, but this makes it clearer. My amp has large soft rubber feet about 1-inch thick which I think isolates it pretty well, but of course it depends on the surface it sits on as well. My CDP has plastic spikes, so may benefit in the arrangement you mention using intermediate surfaces. Good advice and the price is right. Now how do I get those squash balls past my three golden retrievers? LOL! |
Bronze Member Username: Afj
Gaborone
Botswana
Post Number: 40
Registered: Jan-08
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| Posted on Saturday, April 05, 2008 - 05:42 am: |
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hi guys
im a newbie to tube amplifiers. i've heard that the separation of sounds and the overall sound quality that comes through a tube amplifier is better than a solid state amp (pl correct me if im wrong).
i've got the jbl studio L890s. 250w output continuous at 8 ohms with sensitivity of 91db. would a tube amp sound better than a solid amp. my option for the solid is the nad c372 |
Diamond Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 12419
Registered: May-04
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| Posted on Saturday, April 05, 2008 - 12:45 pm: |
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You are simply looking at this all wrong.
It is not the output device that makes the amplifier, it is the design and execution of the amplifier that makes the amplifier.
Particularly with tubes you can have a very good design but cheap tubes will let down the execution of the amplifier.
There are excellent to rotten varities of both solid state and tube - and hybrids have good and bad points also.
If you are listening to the performance of your amplifier to decide whether tubes are better or worse than transistors, you'll get tired of that and want to move on to another thrill.
Don't worry about what's inside the amplifier as long as it's competently built and listen to the music.
If you don't know what live music sounds like, go listen to something performed in front of you before you drop any cash on a hifi.
Establish your priorities based on what you hear in live music that entertains you.
Prioirities need to be more advanced rationalizations than simply wanting "tight bass" and "clean highs".
When you find music in your room that reminds you of music heard live, buy that product.
Forget the rest and enjoy the music.
. |
Bronze Member Username: Afj
Gaborone
Botswana
Post Number: 41
Registered: Jan-08
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| Posted on Monday, April 07, 2008 - 04:56 am: |
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thanks jan that made a lot of sense. its easier to understand when put that way. im happy with the speakers - on different amps different ranges of the music (highs mids and lows) sounded really good. but no amp i;ve used has had it all. i'm looking at the nad c372 now. i;ve heard it on other speakers and liked the amp. havent been able to hear it on the jbls though. guess im in for that now |
Bronze Member Username: Crazywader
Post Number: 16
Registered: May-07
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| Posted on Tuesday, April 15, 2008 - 09:36 am: |
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Francis,
After a lot of time listening to individual components, I bought a NAD C372 paired with Totem Forests and am extremely happy. I tend to listen to a lot of jazz (Spyro Grya - keyboards, guitar, sax, David Sanborn - sax - Winton Marsalis - trumpet, George Benson & Norah Jones vocal w/ instrument accompanyment) and orchestra (Yo-Yo Ma - cello). Just as if they were performing in front of you, you can hear the discrete nuances of the music with no loss or hollowness in bass, the separation in percussion instruments, the soft and hard strokes in a piano, and slide of fingers across strings. However, the CDs I listen to (source: Rega Apollo) must have different recording levels - and you can quickly discern the good from bad CD's (maybe I should have learned more about SACD and reel-to-reel) - yet another factor in what you hear.
The response of solid-state differs from tubes measurably. W. G. Dow, in Fundamentals of Engineering Electronics, writes, "...for any type of vacuum tube, the characteristic curves for any one individual tube may be expected to differ appreciably from the published average characteristics applying to that tube type." Yet it's amazing that the tube amplifier continues to produce a warm sound that brings life to music that draws so many followers over the newer stuff. I'm looking to add an integrated tube amp just for the joy of owning and enjoying a way of reproducing music 'differently.' Will it sound "live?" I think every time I listen to a piece of music I hear something I missed before and I suspect it won't be any different with a tube amp. I doubt I'll ever hear Yo-Yo Ma any better than being in front of him but my system allows me to hear stuff I've missed in the concert hall (8 rows from him and I still hear stuff on the CD I didn't hear at the concert!)
I would guess the others on this board would support me in suggesting that you find a way to listen to as many different individual pieces of equipment that you're interested in with the style of music you prefer. Take your time and enjoy it. |
Platinum Member Username: Nuck
Post Number: 10058
Registered: Dec-04
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| Posted on Tuesday, April 15, 2008 - 08:44 pm: |
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Good post, GT |
Bronze Member Username: Afj
Gaborone
Botswana
Post Number: 48
Registered: Jan-08
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| Posted on Wednesday, April 16, 2008 - 04:43 am: |
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greg
what you described is exactly what im looking for. apart from separation of instruments and all those good things, what i really like is being able to 'feel' the hardness or softness of strokes on an instrument - the forcefulness or softness of the singer - and not just it being an increase and decrease in volume coming through the speakers. if the nad can do that im more than happy. i've got the t163 pre amp and getting the 272 this week |
Bronze Member Username: Lamcam
Stanton,
Ca
Usa
Post Number: 70
Registered: Nov-07
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| Posted on Thursday, May 01, 2008 - 05:20 pm: |
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I just bought a Prima Luna Prologue II. I am running 8 ohm speakers but the sale person recommended to the 4 ohm speaker outputs in the back of the amp. Just wonder why? |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 12600
Registered: May-04
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| Posted on Thursday, May 01, 2008 - 06:16 pm: |
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.
Speakers are spec'd as a "nominal" load, meaning they should be "X" Ohms over most of their frequency range. They do have peaks and dips which will inlfluence how they mate to amplifiers. Tube power amplifiers have higher output impedances than most solid state amplifiers and therefore are more "reactive" to the load of the speaker. Dropping the connection to the 4 Ohm tap lowers the ouput impedance slightly making the amp/speaker a less reactive pairing. I suppose that's why the salesperson made the suggestion. Of course, the salesperson may have been talking out of their @ss.
Did you ask the salesperson why this would be beneficial?
. |
Bronze Member Username: Lamcam
Stanton,
Ca
Usa
Post Number: 71
Registered: Nov-07
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| Posted on Thursday, May 01, 2008 - 06:56 pm: |
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He told me over the phone that I should connect the wire to the 4 ohm although I told him that my speakers are 8 ohm! I did not ask him why at that time. |
Silver Member Username: Magfan
USA
Post Number: 196
Registered: Oct-07
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| Posted on Thursday, May 01, 2008 - 06:58 pm: |
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Silly question::
How do the tube guys CHECK tubes?
In the 'old days', the local grocery, drug store or multi mart had a Tube Checker.
Real handy when the TV went south. BUT, I haven't seen one in 20 years or longer.
Now that tubes are sort of scarce, what do you do? Just curious. |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 12601
Registered: May-04
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| Posted on Thursday, May 01, 2008 - 07:59 pm: |
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Two options that I know of. 1) Take or send the tube to a shop that repairs tube electronics, possibly somebody in your neighborhood who screws around with tubes. Ask around some of the audio clubs if they exist in your area or a ham radio club. 2) Swap the tube with a known good tube. |
Platinum Member Username: Nuck
Post Number: 10162
Registered: Dec-04
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| Posted on Thursday, May 01, 2008 - 08:57 pm: |
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2) is the usual, but 1) is handy to accomplish 2).
Where ya been, Leo?
How's the amp? |
Gold Member Username: Kegger
Warren,
MICHIGAN
Post Number: 2778
Registered: Dec-03
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| Posted on Thursday, May 01, 2008 - 09:20 pm: |
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Me Oh I use one of the 9 tube testers I have! |
Silver Member Username: Magfan
USA
Post Number: 197
Registered: Oct-07
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| Posted on Thursday, May 01, 2008 - 10:16 pm: |
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Working MAJOR hours, Nuck, thanks for asking. They gave me a project to measure thin films using X-Ray Fluorescense. I can't even spell it and don't have the math. Talk about being set up to fail, but I have already made more progress than the REAL (degreed) engineer that got FIRED over this and other omissions.
On the other hand, I live Urban and can probably think of 3 or 4 non-hi end shops to get a tube tested. I know a few hams (thanks Jan, hadn't thought of that!) and
at least 2 electronic repair guys, one of whom is fixing my neighbors Vacuum Tube Zenith (the quality went in, before the name went on) Trans Oceanic.
But what does that do for the poor schmuck who lives in Boise City Oklahoma?
Any of the old Heathkit or Knight Kit stuff out there?
Kegger, Nothing succeeds like Excess!
good answers, all. |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 12603
Registered: May-04
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| Posted on Thursday, May 01, 2008 - 10:49 pm: |
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.
Hey, Kegger. |
Gold Member Username: Kegger
Warren,
MICHIGAN
Post Number: 2779
Registered: Dec-03
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| Posted on Friday, May 02, 2008 - 10:40 am: |
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Hey Jan, and everyone still hangin around here.
Ok OK 9 may be a bit much, how bout more like say 4?
Just pointing out many have there own tube testers now.
And a long day yesterday, work, golf, then the wings rockin!!
-------------------------
Yu'all know what time it is? AKFEST 08 is upon us.
http://www.akfest.com/
I've got some cool things I'll have there, I'll post
a link to a writeup with pics when it's over and done.
(Shh Rick doesn't know it yet, but his "kegafied"Jolida will be there)
And my new scratch build amp based off 6AV5 sweep tubes wired in triode.
Plus much much more that will make up a great experience, (I hope anyway)!
Take care guy's, and gal's! |
Platinum Member Username: Nuck
Post Number: 10164
Registered: Dec-04
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| Posted on Friday, May 02, 2008 - 10:50 am: |
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Great to see ya Kegger! |
Bronze Member Username: Crazywader
Post Number: 18
Registered: May-07
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| Posted on Monday, May 12, 2008 - 08:19 pm: |
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For the select few who truly appreciate the brilliance of a musician and their work, I have experienced something I thought you might enjoy as much as I did. This past weekend I saw Wynton Marsalis at the Kennedy Center in Washington DC. In addition to him playing he had 13 other musicians. The treat was discovering an instrument that I had never heard before - the bass clarinet! And, it was Joe Temperley (who I understand played in the Duke Ellington band) who played a solo, "A single Petal of a Rose." I picked up a recording of the piece - it's an amazing 3 minutes of bliss drawing some significant depth from the speakers never mind the transformers in your amps. As for my system, it performed wonderfully... but there's nothing better than being 8 rows from a master who had everyone talking afterwards! Hope someone out there can relate! |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 12643
Registered: May-04
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| Posted on Monday, May 12, 2008 - 09:30 pm: |
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.
Always great to get out and hear the real thing particularly when it's played by the masters of their craft and art. I wish I'd been there. |
Silver Member Username: Stryvn
Wisconsin
Post Number: 741
Registered: Dec-06
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| Posted on Monday, May 12, 2008 - 09:41 pm: |
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It's always great to hear someone speak with passion about a performance they saw/heard. Glad you enjoyed the show, and then were able to find a recording of the piece! |
Gold Member Username: Mike3
Wylie,
Tx
USA
Post Number: 1318
Registered: May-06
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| Posted on Monday, June 02, 2008 - 01:42 pm: |
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Bo Diddley
R.I.P. |
Gold Member Username: John_a
London
U.K.
Post Number: 4793
Registered: Dec-03
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| Posted on Tuesday, August 05, 2008 - 12:16 pm: |
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Yesterday the right input 12AU7 went down on the Prima Luna PL Two.
I have ordered complete set (2 x 12AU7, 2 x AX7, 4 x EL34), total about £100, manufactured by JJ Electronic.
http://www.jj-electronic.sk/
...but with 4 x EL34 in place of the 4 x KT88. The original KT88s still work OK but I've recently noticed a few problems with distortion at higher volumes. So I thought I'd try EL34s. And they are cheaper (For four, £37 compared with £104). On the phone the dealer said EL34s might go into distortion at lower power output that KT88s. Is this correct? That should make it worse... So I'll compare new EL34s with three-year old KT88s and be tube rolling in no time, I expect, even though I said "not for me" early on on this thread. Until delivery, back to transistors.
I was quoted £250 for a complete Prima Luna set to replace the originals, and £600 for the EAT "upgrade". That's a lot. |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 12884
Registered: May-04
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| Posted on Tuesday, August 05, 2008 - 04:32 pm: |
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.
Tubes aren't cheap nowdays, John. Three to four years of heavy use isn't bad for output tubes. You might try giving the amp a good cleaning. Get the tube pins and sockets clean and see if that helps.
EL34's don't dissipate as much power as KT88's. As a rule EL34's are used in no more than a 50 watt amp with a quartet in place. KT88's can push up to 125 watts with a quartet if they are run fairly hard. The difference between 50 and 125 watts is how much in SPL? Yes, the amp will clip earlier with EL34's than with KT88's.
But all EL34's are not equal. Some will output a bit more and some a bit less. PL should give some indication of approximately how much power you can expect from a generic tube of any type. You do need to make sure the bias voltage on your amplifier is suited to the particular output tubes you have ordered since the PL is a fixed bias amplifier. Some tubes like a bit more bias voltage and some a bit less and you have no simple way to make those adjustments.
. |
Platinum Member Username: Nuck
Post Number: 10621
Registered: Dec-04
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| Posted on Tuesday, August 05, 2008 - 05:52 pm: |
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As opposed to the auto-bias that the PL2 provides(?)
The El 34's are a good solid tube, but I prefer the Svetlana's, meself.
Good solid performance, and a manageable rolloff, depending on what gives up first.
Good low power tubes, in matched seta, just don't ask too much in comparison the the KT88's |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 12885
Registered: May-04
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| Posted on Tuesday, August 05, 2008 - 06:42 pm: |
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.
Nuck - I find myself trying to decipher your posts here lately. As to the auto bias feature of the PL, I don't know the limits of that circuit. As far as I know, it's still possible to buy a tube that might fall outside of the available voltage swing in the design. I could be wrong, I don't know PL well enough to say for sure. I'd say it's better to be certain before you put the tubes in the amp and they aren't working up to snuff. It's also a good idea to know the policy of the tube dealer if such a circumstance should arise, or that you just don't like the sound of the tube you thought was perfect by way of its catalog discription. Do you have the option to return the tubes? Not typically. Exchange? Most of the time but not always.
One of the features of the auto bias on PL is that matched sets are not important. The amplifier will work with tubes that are not closely matched and you are spending your money for matching just because it makes you feel better. In fact, if John found out it was just one KT88 that was bad, he could buy a single KT88 and put it in his amp and the amp would adjust to the new tube.
"The El 34's are a good solid tube, but I prefer the Svetlana's, meself."
I don't know what that means. The EL34 is a tube type made by several manufacturers and Svetlana is a tube manufacturer who makes an EL34. Where's the comparison?
. |
Gold Member Username: John_a
London
U.K.
Post Number: 4794
Registered: Dec-03
|
| Posted on Wednesday, August 06, 2008 - 02:48 pm: |
|
Thanks, Jan and Nuck.
Double the power and other things being equal the SPL goes up 3 dB. Multiply power by 2.5 and, um.... Well a bit more than 3 dB but not much. (He said, waving his hand). A few marks for being in the right ballpark...?
I had an e-mail from the supplier to say the valves would be dispatched today. So, patience. I'll keep the KT88s and see the difference. But as I said, they are getting on a bit, have some sort of deposit inside the glass.
I lugged my Sony ES power amp back from work and plugged it in. Interesting. "Shrill" comes to mind.
Also, it behaves like the PLPL 2 on the 8 Ohms taps in that it sends the Quad ESL 63s into overload protection at the merest thwack of a bass drum. Not good.
I'll write some more tomorrow.
All the best. |
Silver Member Username: Magfan
USA
Post Number: 308
Registered: Oct-07
|
| Posted on Wednesday, August 06, 2008 - 03:04 pm: |
|
Isn't the 'deposit inside the glass' normal?
After all, there should be nothing inside a VACUUM tube but the metallic parts, grids, filaments and such. OH, and lots of Electrons!
The 'deposit' to which you refer is sputtered metal..from the metal parts which pass current.
Sputtering, in tools designed for that purpose, are used in the fabrication of virtually all semiconductor devices, CD/DVD and even car parts. |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 12886
Registered: May-04
|
| Posted on Wednesday, August 06, 2008 - 03:15 pm: |
|
.
Yes, nothing to worry about as far as "some sort of deposit inside the glass" unless it was caused by a tube either overheating or flashing. You would tend to notice the former since the tube would glow bright red and the latter would normally result in some noise through the system. If you're referring to the silvery or bluish deposit at the top of the tube, that's normal and virtually all tubes have that as a result of gasses being evacuated from the tube during the manufacturing process.
. |
Silver Member Username: Magfan
USA
Post Number: 309
Registered: Oct-07
|
| Posted on Wednesday, August 06, 2008 - 04:04 pm: |
|
Jan, agreed that a tube malfunctioning, for whatever reason....(running out of limits for tube?) will do odd stuff, usually bad.
But, could you please explain how the silvery or bluish deposit results from the tube being pumped out?
Now, if it is a discoloration of the envelop caused by....heating the glass to bring it to a point or seal that end, I could see re-crystalization of the glass being a cause.
There is ONE other possiblity. In hi-vacuum practice there is something called a getter pump. You can burn something inside the envelop to consume the last of the oxygen. This would discolor the glass, too. Kind of like an old-style flash bulb! There would be a deposit inside the tube. done correctly it may precipitate on the walls, they are cold in comparison and will never, even being abused, get hot enough for that stuff to evaporate again.
There should be nothing in a tube but the metal of the filaments/grids/heater.
Air should be evacuated to very low levels. Anything else is contamination and will shorten tube life and maybe even change tube parameters.
OH, the silvery stuff is from any of the current carrying parts inside the tube. When enough metal has been carried away from a wire filament, it pops. dead tube. |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 12887
Registered: May-04
|
| Posted on Wednesday, August 06, 2008 - 04:55 pm: |
|
.
https://www.tubeworld.com/index_low.htm
Click "Tube Research".
Various types of deposits:
http://thetubestore.com/ehx6l6gc.html
http://thetubestore.com/tesla6l6gc.html
http://thetubestore.com/tungsol6l6gc.html
http://thetubestore.com/jan6l.html
. |
Gold Member Username: John_a
London
U.K.
Post Number: 4795
Registered: Dec-03
|
| Posted on Wednesday, August 06, 2008 - 04:57 pm: |
|
Thanks again, and thanks to Leo. Listened a bit more this evening. I am not going back to solid state.
All the KT88s have the same silvery-gray stuff in a round patch in the same place halfway up the inside wall of the glass tube. It wasn't there when they were new, and has accumulated with time. "Sputtering" could be correct. I have no reason to suppose this has any sonic effect.
I have a sort of trade off with this system, regardless of source. Dead silence for four seconds on some peaks from one or other channel, versus some distortion at hight levels especially from upper mid-range like choirs or horns. Even harmonic and therefore not actually painful, but not good.
The new Quad ESLs have greater power handling. I browsed a bit for info last night but you can buy cars for that price. The Quad ESL63 "Pro" made first for Philips recording engineers and then in production for export to US must have been really something. I am not going back to electromagnetic speakers, either. No way. |
Gold Member Username: John_a
London
U.K.
Post Number: 4796
Registered: Dec-03
|
| Posted on Wednesday, August 06, 2008 - 05:07 pm: |
|
Thanks for the links, Jan. I ordered from these people over this side of the "pond";-
http://www.sequoia.co.uk/eshop/browse.php?mc=Other&sc=Thermionic%20Valves&pg=1
The man who kindly called me back seemed to know his stuff. And any friend of Mr Tesla is a friend of mine.... |
Silver Member Username: Magfan
USA
Post Number: 310
Registered: Oct-07
|
| Posted on Wednesday, August 06, 2008 - 06:22 pm: |
|
Good link, Jan, if not quite scientifically accurate.
Thin films, and I mean in the sub-micron range, 10,000angstroms and below, will have color fringes based on thickness. In my line of work, I seldom use instruments to tell the thickness anymore, since I can judge film thickness of Silicon Oxide and some Polysilicon films without aid to sufficient accuracy.
The rainbows at the edges are just film thickness variations.
The only reason to continue to getter something in a vacuum is if there is a leak to atmosphere. Once all the oxygen and other bad guys have been consumed and rendered inert...in some metalic film, there is no reason to continue, and no way to continue, the reactants have nothing to react with...
Judging the quality of a tube by the color and quantity of such deposits strikes me as some kind of voodoo.
The electrical test at the bottom of the link is of course, the right thing to do. |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 12889
Registered: May-04
|
| Posted on Wednesday, August 06, 2008 - 09:16 pm: |
|
.
"Judging the quality of a tube by the color and quantity of such deposits strikes me as some kind of voodoo."
Yep! A better tube is a better tube, doesn't matter what the color of the residue is. When you get down to picking your tubes by color, I'll be in the other room listening to music.
. |
Silver Member Username: Magfan
USA
Post Number: 312
Registered: Oct-07
|
| Posted on Wednesday, August 06, 2008 - 09:46 pm: |
|
Yep, coming soon to a boutique store near you::
Tubes in Designer Colors. |
Gold Member Username: John_a
London
U.K.
Post Number: 4797
Registered: Dec-03
|
| Posted on Thursday, August 07, 2008 - 03:22 pm: |
|
Tubes arrived.
I fitted the whole new set in place of the old.
Just wonderful. No distortion; no trip-switches thrown on the speakers.
And the sound... There are not words. I remember Rick Barnes said "liquid". That is vaguely in the right direction.
Early on in this thread, I inclined to the view that all amps are much the same. This view is total, demonstrable nonsense.
The 100 W per channel Sony sounded tinny and lifeless - and took out the speakers.
The "entry level" Prima Luna with downgraded EL34 in place of KT88 should give only about 35 W per channel. But it sounds like the real thing – more scale, depth, richness, nuance, compared with the Sony. And it does NOT take out the amp. Maybe the Sony's power rating more Volts than Amps. |
Gold Member Username: My_rantz
Australia
Post Number: 1977
Registered: Nov-05
|
| Posted on Thursday, August 07, 2008 - 06:04 pm: |
|
Good to see the new tubes worked out for you John. I hope all else is good in your camp.
Cheers M.R. |
Gold Member Username: John_a
London
U.K.
Post Number: 4798
Registered: Dec-03
|
| Posted on Friday, August 08, 2008 - 03:39 am: |
|
Well, it's still under review, M.R. Good to be in touch again. I think I remember Kegger having something to say about EL34s; possibly "warm". I put this to the chap in the shop who commented on the difference between those and KT88s. He said, roughly, he thought that talking about sound of different valves was like discussing the sound of cables.... (smiley) For him, an electronics guy I suppose, the point of a KT88 is that it delivers the most power you can get out of that basic design, and so will deliver more volume that an EL34 for a given amount of distortion.
There are several other random observations on the JJ valves/tubes. I be back. All the best.
PS Rick and Jan were the two most persuasive tube advocates, as I recall. I thank them, and others. It really is amazing to hear the difference between my two amps. Adjusted for inflation, they are not far from the same price bracket and the Sony, on paper but definitely not to the ears, delivers more power. Probably that should read "voltage" which is why the speakers flip their switch.
Whether there is a general rule being followed I have no idea. There must be solid state amps that sound at least as good or better than the PL, and tube amps that sound like rubbish and overload speakers even at moderated volumes. Who knows... |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 12895
Registered: May-04
|
| Posted on Friday, August 08, 2008 - 09:35 am: |
|
.
The original Quad amp that ran the 57's was only endowed with a few watts, John. It's not the amount as much as the quality of each watt. The idea of lots o'watts and lots o' speaker is hogwash perpetrated by manufacturers of cheap crap. There are systems that require both, but they are ill designed for the task of being transparent to the music IMO.
From your brief replay of your conversation with the tube retailer, I would tend to agree. Tubes sound like the circuit they are in and you can't say a tube sounds like "this" or "that" until it's in a circuit. Overall, I'd say an EL34 doesn't sound like a KT88, but don't take "warm" as anything more than the alternative statement that the KT88 is "cold". Neither is necessarily true until it's placed in the circuit your amplifier designer built.
On an amplifier with user adjustable bias you could run the bias higher or lower and change a warm sound to a cold sound with a twist of a screwdriver - also affecting the other parts of the amplifier and the reliability of those parts. So, even within the same amp, the same tube can sound unlike itself with a different bias voltage running through it.
And your small signal tubes certainly do affect the sound quality. Changing a 12AU7 will make the amp sound not like it did with a different 12AU7 for several reasons. It can be frustrating because everything you change on a tube amp - and some would argue a solid state amp as well - caps, wires, sockets, can make subtle changes to the sound quality. Tube rollers have mulitple sets of tubes and swap until they "tune" to the sound they prefer. Other than financially that's not bad when you have a good sounding amp to start with and a top notch reference for what you want to hear. You can round, or sharpen, the tones of a vocalist or affect the attack of a pianist. The biggest problem comes when you start thinking an entire group of tubes sounds "this way". They don't really, they sound the way they sound once they're in your amplifier.
But, you have that ability to tune with a tube amp. What can you do with the Sony?
. |
Gold Member Username: John_a
London
U.K.
Post Number: 4799
Registered: Dec-03
|
| Posted on Sunday, August 10, 2008 - 06:21 am: |
|
Thanks, Jan. Received and understood.
Agreed, I do not know which components of the complete set have made the difference. I propose to listen some more, enjoy the music, and then put back the KT88s and see. Bearing in mind: 1. They are KT88s; 2. They are three years old; 3. They are from a different manufacturer (I assume, though the "PrimaLuna" logo on the glass does not tell me who made them). I'll save further speculation until I have a result from that test.
One possibility that occurs to me, and please tell me if it is ludicrous, is that the EL34s are uniformly cylindrical in shape, while the KT88s have a larger diameter at the top, looking a bit more like inverted bottles. I would guess the KT88s are therefore more susceptible to microphonic feedback. I suppose I could test this by putting the amp in another room.
Random observations for nerds.
1. (Totally trivial) The JJs have the logo printed on the back of the valve/tube as they sit in the Prima Luna. So no advertising is displayed - it faces the transformer housing, not the user. The output valves' seating has the plastic notch towards the back on the PL amplifier, the PL logo therefore being printed on the opposite side of the tube to the notch, and facing the front. The JJ logo is on the same side as the nothc. Which, if either, is standard?
2. Possibly not trivial. With the PL set, the two 12AX7s glowed hardly at all - much less bright than the two 12AU7s. Always, sonce day one. With the JJ set, the 12AX7s glow just as much as the 12AU7s. Looks much nicer nice and better balanced - and this is the "third party" tube. This must in itself have some sonic effect, surely - in the PL set-up, the 12AX7s are generating less light, heat and power that the 12AU7s.
3. Terminology. "12AX7" supplied as "JJ" are named "ECC 83 S". "12AU7" is JJ "ECC 82". Lord knows why.
4. It still sounds darned good.
5. JJ comes from the Slovak Republic (the "other half" of former Czechoslovakia) yet Tesla (which they used to be called) was a well-know Croat. Strange.
Reference; http://en.wikipedia.org/wiki/Nikola_Tesla
Totally fascinating. Friend of Mark Twain, for example. And a fruitcake in other aspects of life. Totally irrelevant, of course. I guess I take these things too seriously....!
Now it is Sunday and I can do some listening.
Best wishes,
John
PS Sony; Agreed. "Quality" of Watts... Hmm... The only "quality" I can begin to comprehend is that
1 Watt = 1 Amp at 1 Volt
So
Power (in Watts) = Current (in Amps) x Potential difference (in Volts)
So you can have your Watts composed of Amps or Volts in different measure, like area being composed of length and breadth.
Now the Quad spec says they go into overload protection at 40 V. By Ohm's Law that would be at 5 W into 8 Ohms and 10 W into 4 Ohms. So I think I am beginning to see why the speakers prefer the 4 Ohm output taps on the amp. Putting it another way – the Quads prefer their power in Amps. Probably the Sony is reaching its power target in Volts.
This doesn't explain the sound, of course... |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 12905
Registered: May-04
|
| Posted on Sunday, August 10, 2008 - 12:09 pm: |
|
.
John - Oh, you Europeans! Americans don't know from Croats. You all look alike to us.
1) There is no standard. My Mac amps, being push pull with one output tube per channel seeing a reversed phase, have the tubes one way and then reversed in the position of the socket. It makes for cleaner internal wiring in the McIntosh circuitry.
2) No real sonic effect. The tubes are what they are. Some tubes glow brightly and some do not. If the 12AX7 is downstream of the 12AU7, then there might be a slight change in the relative levels of current heading to the 12AX7. If the 12AX7 is ahead of the 12AU7, then the 12AX7 should not see what the later tube is doing. As an integrated, one set of tubes is dedicated to the pre amp functions and won't have much effect on the power amp side of the unit where the other small signal tubes reside as driver tubes.
Though a 12AU7 has a gain factor of 20 (12AX7/100) no two tubes are exactly alike. Most tubes that come from one design batch will be close to one another but two 12AU(X or T)7's from different manufacturers or even different designs of the same model of tube by the same company are likely to have slightly different gain characteristics. I just swapped out the 12AX7 phase inverters in my amplifiers and had a substantial change in gain from what should be a fairly benign tube in that circuit.
3) The "12" series tubes are using American production numbers. The "EC" tubes are European in manufacturing origin and basic design. They are interchangebale for the most part. 6550's become KT88's, 6L6's become KT66's. There are some variations in the design and construction of a 12AX7 vs. a EC83 and even a 83ECC. Tube afficianadoes go gaga over which tube has such and such a number and which tube has a certain color base. The largest problem here, as I see it, is there are unscrupulous dealers of NOS tubes who rebrand tubes to be something they are not or simply lie to an unsuspecting customer about what they are selling. It gets down to knowing that certain plants for a specific manufacturer always placed a triangle stamped into the bottom of the tube's glass envelope.
Some Mullards/Ampex/RCA, etc. were sold under another company's name and some were sold in bulk as white box tubes. A really knowledgeable tube retailer or hunter of tubes can usually find a white box Mullard/Ampex/RCA etc. by looking closely at the tube. They pay less for a quality tube because the name isn't on the tube. It gets to be a big game after awhile. My rule is don't chase the exotic stuff and always buy from a reputable dealer with whom you feel a trust.
Not a recommendation, just an example; http://www.vacuumtubes.com/6dj8.html
The Quads probably prefer the 4 Ohm tap because it better matches the input impedance of the Quad's transformer. Quad's do require some current, if you'll remember the original Quad circuit was a "current dumping" type which is still in use today although rearranged for transistors. The reissue of the Quad 22 uses the same circuit as Walker's original and is, from what I understand, still suited to the entire Quad line of speakers though limited in output watts to roughly 20-25 watts.
While tubes are current driven devices they are not high current output devices. Probably your Sony has more current potential than the PL, it just can't deliver it with the capability of the PL. I can't remember seeing a spec on the PL for current delivery but I would expect it to produce no more than 3-5 amps at 8 Ohms depending in some part on the tube compliment.
. |
Gold Member Username: John_a
London
U.K.
Post Number: 4800
Registered: Dec-03
|
| Posted on Sunday, August 10, 2008 - 02:56 pm: |
|
Jan,
Many thanks. Interesting. Requires thought. Will be back. Definitely.
Correction of my last post...
"Now the Quad spec says they go into overload protection at 40 V. By Ohm's Law that would be at 5 W into 8 Ohms and 10 W into 4 Ohms".
Please delete "W" and replace with "A". Sorry about that!.
Ohms = Volts/Amps
The speakers go silent and present a dead short to the amp at 40 V. This must be 200 W at 8 Ohms (5 A) and 400 W at 4 Ohms (10 A).
So the amp reaches the speakers' overload voltage at twice the current with output for 4 Ohms than with output for 8 Ohms.
Will pause and reflect on Jan's informed previous post. "Europeans all look alike". Americans. No wonder Wesley Clarke would have tipped us into WW3 in Kosovo, if not for the insubordination of Mike Jackson....
Best wishes. |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 12906
Registered: May-04
|
| Posted on Sunday, August 10, 2008 - 06:51 pm: |
|
.
Wesley Clarke was flying the planes so high he couldn't see that you all look alike. |
Gold Member Username: John_a
London
U.K.
Post Number: 4801
Registered: Dec-03
|
| Posted on Sunday, August 10, 2008 - 10:28 pm: |
|
Sigh... He wasn't flying planes, but sitting in an office giving other folks orders to block the runway at Pristina airport.
Thanks for the information, Jan.
I had a brief attack of HiFi dissatisfaction and upgrade hunger last week. I think I'm over it, now. At the peak of the infection I checked out the current Quad tube amps and ESL speakers. Expensive. I think I'll stick with what I've got. The complete set of new tubes alone was the end of distortion and overload, even at higher volumes than before. Wonderful. I'll try to figure out which part of the set did it by a process of elimination, over time. Depending on the outcome, I'll consider KT88s. I am comfortable with JJ and that dealer I mentioned. I can't find much evidence of actual shops in the sense of retail premises one can walk into and ask advice. Anyway, if sequoia.co.uk will phone back with knowledge and advice, and deliver next day, that's a recommendation.
HiFi seems to be an area where people like to congregate around names, logos, and the colour of the box, even when the thing inside is, in itself, the same.
I also found this link on extant tube manufacturers as of December 2005;-
http://www.vacuumtube.com/Mfg.htm
Good to see there are still US ones.
As regards PrimaLuna, they seem a slightly at the edge of sanity, but who cares. If it works, which it does, I'll keep it. The build quality suggests longevity, and the PL2 would probably have withstood Wes Clarke on active service.
PL have quite a wider range now, including monoblocs and so on. I'd like to install the phono stage eventually. Perhaps I'll try separates, one day. Casual inspection suggests they change tubes and give the result a new model number. US Web site includes pdf files of owner manuals etc;
http://www.primaluna-usa.com/ |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 12908
Registered: May-04
|
| Posted on Sunday, August 10, 2008 - 10:54 pm: |
|
.
Most of the electronics manufacturers who use tubes strip the name off the tubes they buy and have their own name resilk screened. Even some tube retailers such as Groove Tubes do the same thing.
The "people who brought you PL" have a new higher end product line with a new name. I've seen a few ads starting to appear in Stereophile and TAS. I'll find the ad and post the name.
. |
Gold Member Username: John_a
London
U.K.
Post Number: 4802
Registered: Dec-03
|
| Posted on Monday, August 11, 2008 - 12:35 am: |
|
Thanks, Jan. I thought I'd replied but it is not here.
Groove Tubes are JJ Tubes according to the first link in my last post.
Going back; "I can't remember seeing a spec on the PL for current delivery". I can't find that in the manual. There is Stereophile review of the PL1 (with its EL34 output tubes) with Atkinson test results and Dudley waxing lyrical about performance with Quad ESLs...
http://www.primaluna-usa.com/reviews/stereophilepro1.pdf |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 12909
Registered: May-04
|
| Posted on Monday, August 11, 2008 - 10:09 am: |
|
.
Just to clarify the point, Groove Tubes is primarily a tube reseller. They are not a tube manufacturer such as Svetlana or JJ. They buy up lots of tubes and rebrand them after testing and categorizing them. They began back in the late 1970's and their clientelle was then and is now primarily musicians. My first set of replacement tubes I ever bought for the Macs were Groove Tubes all the way from phase splitter to outputs. (I think that retube cost me about $200 for two amplifiers back in 1982.) Recently, they have had existing companies manufacture tubes for their line and these are relabelled as GT's, from what I understand there are even some tubes manufactured exclusively for GT.
I haven't shopped GT lately but perviously they had a system of testing that was really aimed at musicians which determined the point of overdrive (distortion) on a bell curve type comparison and it's amount as the tube went into clipping. This information is important to a musician looking for a particular sound from their amplifier.
What this meant to me, in a home audio application, was I could choose output tubes that "sounded" more like classic tubes or more like classic transistors. The scale is 1-10 and I don't remember what I chose 26 years ago, I think I went with an "8". They were not the best sounding tubes I've ever used but they did quite well and I do still have the set as backups.
. |
Gold Member Username: John_a
London
U.K.
Post Number: 4803
Registered: Dec-03
|
| Posted on Monday, August 11, 2008 - 12:02 pm: |
|
Thanks, Jan.
I should have written "Some Groove tubes are JJ tubes". There is clearly a place for resellers. Personally I'd rather know who actually made stuff. "PrimaLuna" tubes are expensive and obviously made somewhere else. There is also an "EAT" "upgrade" that comes in a stylish wooden box, like champagne. http://www.euroaudioteam.com "Made in Czech Republic" and, according to Kessler "the valve equivalent of Viag_ra". http://www.euroaudioteam.com/pdfs/eat_kt88_hfn_0705_4web.pdf
Double sigh...
Meanwhile, in the real world.... |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 12910
Registered: May-04
|
| Posted on Monday, August 11, 2008 - 04:46 pm: |
|
.
"There is also an "EAT" "upgrade" that comes in a stylish wooden box, like champagne."
The deal is what you believe it to be, John, not what you pay. |
Gold Member Username: John_a
London
U.K.
Post Number: 4804
Registered: Dec-03
|
| Posted on Monday, August 11, 2008 - 05:57 pm: |
|
I'd say the deal is neither of those.
The deal is what it is.
Admittedly things get in the way of finding out. |
Gold Member Username: Mike3
Wylie,
Tx
USA
Post Number: 1421
Registered: May-06
|
| Posted on Tuesday, August 26, 2008 - 12:30 am: |
|
This is an off-shoot from Tawaun Williams' thread "What has everyone bought since I've been gone,and what direction is everyone going?" as this has occurred after TW's OP, but here goes anyway. 
I alluded to earlier (on another thread) that JV provide me a host of 12AX7's for messing around with my pre-amp. I put the Golden Dragon in my phono gain stage and was taken aback by the difference. Well I discussed this a bit, read a bit more, got the buyer beware, someone's reject bin, yadda yadda yadda, level setting advice.
Trusting my sources I decided to exercise caution when buying tubes for tube rolling.
I called Rogue Audio directly and spoke with Mark O'Brien today. I figured they had to try different tubes in their gear and for reason of cost or whatever, settled on the JAN Phillips 12AX7 pair and 12AU7 pair and some Russian 6SN7s (set of 4). I was not exactly right. They put in what sounded good and would be convenient for their clients to buy new.
In discussing what I liked and did not like about the Golden Dragons Mark mentioned RCAs, Sylvanias, Tung-Sols, and maybe one or two others.
After more discussion about characteristics and such I bought a complete new set of tubes for my pre-amp. All Tung-Sols, all original 40 year old Russian tubes. He is testing them in their shop's Magnum 99 and will ship them tomorrow.
He says I will really like the improvement. Next week cant' get here fast enough.
Plus I have these other 12AX7s to play with later!!! I just love this sport! |
Gold Member Username: My_rantz
Australia
Post Number: 1985
Registered: Nov-05
|
| Posted on Tuesday, August 26, 2008 - 01:03 am: |
|
Well, if you get good enough Mike, the next Olympics is only 4 yrs away! [grin]
Bet Mark is glad he's finally getting rid of that 40 yr old stock! [double grin]
Kidding aside - glad you're having so much fun with your gear. It'll be good to hear the outcome.
Cheers M.R. |
Platinum Member Username: Nuck
Post Number: 10676
Registered: Dec-04
|
| Posted on Tuesday, August 26, 2008 - 06:07 am: |
|
That is going to give you a whole different sound, Mike.
I hope you like it. |
Silver Member Username: Jazzman71
Phoenix,
AZ
USA
Post Number: 236
Registered: Dec-07
|
| Posted on Friday, August 29, 2008 - 12:01 am: |
|
Two tubes shy of a decathlete by my count, MR. My rig uses Russian 6SN7s (Electro-Harmonix). Mike, there's something strangely cool about using Russian tubes. I like the sound and it took no time at all to get used to that second click when I pick up the phone. |
Gold Member Username: Mike3
Wylie,
Tx
USA
Post Number: 1436
Registered: May-06
|
| Posted on Friday, August 29, 2008 - 12:29 am: |
|
Priceless Neil!
I got all excited today when the receptionist told me I had a Fed-Ex box up front. Turned out it was a vendor shipping me a couple of replacement parts. Arghh!
The wait continues. |
Gold Member Username: Mike3
Wylie,
Tx
USA
Post Number: 1437
Registered: May-06
|
| Posted on Friday, August 29, 2008 - 04:24 pm: |
|
Wait is over!
Now how often does that happen?
This is going to be a helluva weekend!!!!
I think... |
Platinum Member Username: Nuck
Post Number: 10704
Registered: Dec-04
|
| Posted on Friday, August 29, 2008 - 04:34 pm: |
|
Why do I imagine my phone ringing during sax for a tube review?....
hehehe, let us know Mike, it will take a few days, just like the Svets I put in my little amp |
Gold Member Username: Mike3
Wylie,
Tx
USA
Post Number: 1438
Registered: May-06
|
| Posted on Friday, August 29, 2008 - 04:39 pm: |
|
You really did mean sax I hope?
Doh!!! |
Gold Member Username: Mike3
Wylie,
Tx
USA
Post Number: 1446
Registered: May-06
|
| Posted on Thursday, September 04, 2008 - 10:31 pm: |
|
The Tung-Sols were delivered and boy am I ever glad I went to Rogue Audio and worked this out with their Engineer Mark O'Brien. Not only did they test out the tubes again prior to shipping them to me he labeled each of the tube boxes as to its individual proper placement in my Rogue Audio Magnum 99 Pre-Amp. This company's idea of Customer Service is gold!
The tubes made a significant change in my sound, much more than I could have anticipated. The soundstage grew laterally and while the back stayed in place the front of the soundstage is closer, with the height about 6 inches higher.
The bass was tighter (incredible the snap in drums on 10,000 Days [Tool]), it does not drop as deep by about 5 Hz. The pacing of the bass has improved as well.
The vocals seem more natural and relaxed.
Instruments, while given more independence in space, time better with one another, creating a better sense of the performance for me.
I do not get the highest peak in the treble range, but I get a cleaner, more engaging horn and string presentation.
It took a bit for me to figure this last part out, but the tubes are quieter than the ones they replaced. When I realized how much so it was embarrassing that I did not pick up on this right away.
I am very pleased with this upgrade and damned glad I went to the manufacturer, Rogue Audio, for their input, and ultimately the purchase of the tubes from them. |
Platinum Member Username: Nuck
Post Number: 10745
Registered: Dec-04
|
| Posted on Friday, September 05, 2008 - 06:34 am: |
|
Excellent Mike!
It is seldom that you have to give up so little for such a pleasant result. |
Gold Member Username: Mike3
Wylie,
Tx
USA
Post Number: 1457
Registered: May-06
|
| Posted on Monday, September 15, 2008 - 02:01 pm: |
|
Sadly...
Richard Wright, a founder member of Pink Floyd, has died at the age of 65 after battling cancer.
http://ukpress.google.com/article/ALeqM5hWIGm5l-yoyRo6pTklrXqJB3BnmA |
Gold Member Username: John_a
London
U.K.
Post Number: 4808
Registered: Dec-03
|
| Posted on Saturday, September 20, 2008 - 02:28 pm: |
|
To follow up, as promised, from Aug 11. One of the "matched quad" of EL34s was suspect from day one having a visibly misaligned grid. Last weekend it introduced distortion into whichever channel it was on.
I e-mailed the supplier http://www.sequoia.co.uk/ No reply to date. Clearly the premium for "matched quad" sets is not their department. Nor, for that matter, customer service. This confirms all my concerns about internet ordering. They have my money; I have their defective product. Never mind, this is another story....
Meanwhile, I re-installed the original "PrimaLuna"-badged KT88 output valves/tubes. Result? Wonderful sound. I really think this system I have is now as close to reality as I could ever get. Indistinguishable from the first impression with the EL34s.
So it must have been one or more of the input valves/tubes that needed replacement.
Ask me for a breakdown in the difference between the sound from EL34 and KT88 and I could make things up, but not actually report anything I could hear. I seem to recall Kessler said "like the difference between pepsi and coke (if you catch my drift" so I assume he would prefer to advertise his recreational habits at the expense of saying anything intelligible about the subject in question, and so he probably can't hear any difference either.
Oh, for good old-fashioned audio dealers.
Apologies for interrupting. Sorry to hear about Richard Wright.
Best wishes. |
Gold Member Username: My_rantz
Australia
Post Number: 1999
Registered: Nov-05
|
| Posted on Sunday, September 21, 2008 - 06:56 pm: |
|
Glad you have it back to enjoyability John. Ah, the beauty of a quality solid state amp . . .
. . . excuse me while I don my fire suit |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 13018
Registered: May-04
|
| Posted on Monday, September 22, 2008 - 09:21 am: |
|
.
That's the problem with you Aussies, no sense of adventure. Give me an amp that sparks, spits and throws flame now and again over one that just sits there. Excuse me now, I have to help synchronize the three side draft carburetors on my friend's '61 MG Midget - if he can get it started. Now that's adventure! Then we're going hang gliding in a hurricane.
Live it on the edge, guys, you only go 'round once.
. |
Gold Member Username: My_rantz
Australia
Post Number: 2002
Registered: Nov-05
|
| Posted on Monday, September 22, 2008 - 06:19 pm: |
|
Naw Jan - living on the edge is what we do when we're not listening to music. Now where did I put my croc skinning knife?
A 61 Midget - that would be a bug eye model would it not? I craved those in my youth but ended up getting a B a few years later. |
Gold Member Username: John_a
London
U.K.
Post Number: 4809
Registered: Dec-03
|
| Posted on Friday, September 26, 2008 - 07:10 pm: |
|
Bought a Triumph Spitfire Mk III, myself. Ah, the fond memories of applying rubber tubing to the lug 'ol to assess the intensity of the hiss from each of the twin SU carburetors whilst adjusting the mixture. Looking back, I think I should have gone for a Mk I MG Midget aka (over here) Austin-Healey "Frog-Eye" Sprite. Regrets, I've had a few.... Lucky to be alive after driving that thing. Really.
MR - you had an MGB? I used to dream of an MGB....
Anyway, this hifi I have is brilliant and I am sticking on pontoon. Son made a birthday card with a picture of me adjusting the volume wearing the regulation fireproof suit with Mrs A standing by with an extinguisher. I now run the amp without the safety cage. It scares the cats, too.
Thanks for comments. Good to see you, Jan and MR.
By the way, the LCD TV died. Good. I dance on its grave. After 6 weeks of no TV I convinced them I was temporarily sane and we bought a projector. Optoma 720p HD. Mounted (by me) on ceiling; projecting onto wall. Very fine. 82" screen, fraction of the cost of one of those hideous plasmas. And when it's turned off, there's nothing there. Just a wall, and the music.
Whole family agrees this is the way.
This all required total rearrangement of speakers, cabling, etc etc. Audio now better that ever. Fits the room better.
Wrong thread, I know.
All the best. |
Platinum Member Username: Nuck
Post Number: 10902
Registered: Dec-04
|
| Posted on Friday, September 26, 2008 - 10:05 pm: |
|
A tip of my hat to you, John.
Excellent choice in the projector, however many bundle of snakes of techno-tripe that invovlves(or could). You seem on top of it mate, so break out the popcorn!
Enjoy the fun, our friend, but do not neglect the Quads. |
Gold Member Username: My_rantz
Australia
Post Number: 2006
Registered: Nov-05
|
| Posted on Saturday, September 27, 2008 - 01:38 am: |
|
That's right John - it was the bug-eye Sprite I was thinking about. My dream car early in my youth was the Austin-Healey 6. The MG was a '67 model, the first here with Overdrive and was immaculate. Unfortunately we got it not long before Mrs R fell pregnant. When she was about 8 months, she couldn't get out (it had Recarro buckets) and she had to roll out into the gutter. Needless to say she wasn't impressed and a second car was purchased the next week. Then, with a new baby, a dog etc, etc, the B had to go. It brought a tear to my eye I can tell you. My brother had a TC at one stage, rough as gutz but it sure looked good!
Good call with the projector. Big, big picture. We have been enjoying Blu-ray here with what titles are available. Music system is good and will remain as is for some time, though trying to make music is lessening my listening time.
Love to see that card John! |
Gold Member Username: John_a
London
U.K.
Post Number: 4810
Registered: Dec-03
|
| Posted on Saturday, September 27, 2008 - 10:49 am: |
|
Nuck,
Thanks! "do not neglect the Quads." No way! I'm in it for the sound. Video can, admittedly, sometimes add that little bit extra to lifelike sound. I can be a definite plus in movies, for example..... Well, some movies....
M.R. Thanks, too! There was an Austin-Healey 3000 (meaning cc) - even better than the MGB. "6" probably means cylinders, so I think those may have been two names for the same car. MGB was a 4-cylinder 1800 as I recall. My cousin had one but gave it up for the same reasons as you.
I'll try to find the card.
Sorry to ramble, I should be posting on Old Dogs, but back to topic (slightly)....
Youngest son (14; the one who teases his elders and betters about valve amps) took delivery this morning of a Vox 30 W amp for his Epiphone guitar. I was not consulted!. Point is, blow me down, the amp has a valve/vacuum tube, a 12AUX, takes time to warm up, has an output transformer, plus, in the middle, a digital processor fed a signal from a 24 bit ADC. Purpose of the processor is to emulate 11 different classic guitar amps. The manual specifies which ones, and itemizes the valves/tube each contained.
So take that, all tubophobes...!
When did anyone design a valve amp to make it sound like solid-state....?
http://www.voxamps.co.uk/valvetronix/
To my ears, the processor on some settings creates exactly the sound my PrimaLuna PL2 gave when the input tubes were shot.... So Vox needs to collaborate with Korg to produce a solid-state processor to emulate the sound of clapped-out tubes....?
"You couldn't make it up".
I'll try and find a picture. |
Platinum Member Username: Nuck
Post Number: 10906
Registered: Dec-04
|
| Posted on Saturday, September 27, 2008 - 11:05 am: |
|
John, so many players work long and hard to exaust the tubes and get the 'right' sound.
Doesn't last for long, but hopefully the engineer gets the tracks down before the tubes kack.
MR, 'rough as gutz' reminded me of high school days, trying to tune twin solex side drafts to propel the little TC in its own retina-seperating washboard fashion.
Anyone who drove it too much might be in need of a surgeon or test tube to have kids. |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 13022
Registered: May-04
|
| Posted on Saturday, September 27, 2008 - 11:32 am: |
|
.
"John, so many players work long and hard to exaust the tubes and get the 'right' sound.
Doesn't last for long, but hopefully the engineer gets the tracks down before the tubes kack."
Gatemouth Brown figured it out in the '50's and taught it to those white blues players in England in the '60's. It's part of the Texas Blues sound that he pioneered after the second WW.
It's called "overdrive". Overload the front end of the amp with too much input/gain and it sounds very much like "clapped out" tubes. Very rough and no real distinction between EL34's and KT88's but it's a start until you can afford something with valves (not the MG kind of valves). That little Danelectro amp I have has only three controls; volume, tone and gain. The owners manual has a dozen suggestions for how to emulate the generic sound of various amplifiers by using the position of these three pots. At 2 1/2 watts it's not totally convincing if you try to sound like Clapton, Page or Buddy Guy playing through a 100 watt tubed Marshall stack but those three knobs do work an amazing amount of change into the amplifier's sound. I also own a smaller version of the Vox amp your son owns, John, and it too does some amazing things with its simple controls running through an impressive-for-the price digital simulator.
http://www.youtube.com/watch?v=8R8H8CNjjXo
http://www.youtube.com/watch?v=EGaJAmnSW7Y
. |
Platinum Member Username: Nuck
Post Number: 10907
Registered: Dec-04
|
| Posted on Saturday, September 27, 2008 - 11:42 am: |
|
Cool, JV.
A kid I knew had a set of pedals for a lot of stuff as well, but never really got 'clapped out' just right. |
Gold Member Username: John_a
London
U.K.
Post Number: 4811
Registered: Dec-03
|
| Posted on Saturday, September 27, 2008 - 11:58 am: |
|
Oh, wow. Here I was typing thanks to Nuck for recollections of an MG TC ... Thanks, Nuck!
Cool, Jan! I'm going to ask son's permission to post video clip. His first shot with the Vox VT30. Meanwhile, a still....
By the way, just a glimpse of a Quad ESL63 to right of frame....
As you see, we live in a time warp. |
Platinum Member Username: Nuck
Post Number: 10911
Registered: Dec-04
|
| Posted on Saturday, September 27, 2008 - 01:48 pm: |
|
Make anything of the time that you have John.
Seems your boys survived the MG thing, LOL!
Post away, John. The thread will be what it is.
I wanna see MR and his axe. |
Gold Member Username: My_rantz
Australia
Post Number: 2007
Registered: Nov-05
|
| Posted on Saturday, September 27, 2008 - 04:02 pm: |
|
No way Nuck!
John, I almost bought a similar amp, but got the Vox AC15 - it's an incredibly powerful (and heavy) all valve beast with distortion up the wazoo with ajustments to the master volume and gain controls. Wonderful amp! |
Platinum Member Username: Nuck
Post Number: 10912
Registered: Dec-04
|
| Posted on Saturday, September 27, 2008 - 08:03 pm: |
|
I know the answer, but will put forth the question anyhow.
How can we mostly all enjoy accurate reproduction of our favorite music, yet value so highly the distortion that makes some of it so special?
And creating the distortion so pleasing, yet trying so hard to reproduce it so faithfully?
Thankfully, when people think I am strange, I can seek solice here. |
Gold Member Username: My_rantz
Australia
Post Number: 2008
Registered: Nov-05
|
| Posted on Sunday, September 28, 2008 - 12:40 am: |
|
Ever try to play Santana without distortion? It's an accurate part of reproduction of his guitar work as it is with many others back through the decades. But you know this - you stated so :-)
But it's getting that faithfull reproduction - that ain't easy! Nor is an unfaithfull reproduction!!!! |
Gold Member Username: John_a
London
U.K.
Post Number: 4813
Registered: Dec-03
|
| Posted on Sunday, October 12, 2008 - 02:08 pm: |
|
Sorry I'm now a once-a-week poster.
Nuck - we want the original distortion: nothing added; nothing taken away. Don't you agree?
In the audio system itself, we want no distortion. Or, at least the closet approach to the original that we can get.
Is that the answer.....?!
Hi, MR! |
Gold Member Username: Mike3
Wylie,
Tx
USA
Post Number: 1490
Registered: May-06
|
| Posted on Sunday, October 12, 2008 - 09:11 pm: |
|
Uh, John, that was two weeks...
must be the time warp you are existing in.
LOL! |
Gold Member Username: John_a
London
U.K.
Post Number: 4814
Registered: Dec-03
|
| Posted on Saturday, October 18, 2008 - 11:55 pm: |
|
The post of the week before was on another thread, Michael.
Yes, I just checked - Oct 4. Well, 8 days, it's close....
http://forum.ecoustics.com/bbs/messages/1/21154.html
I was reminded of the thread that Jan started called "Do you listen" where we all fought and argued. Seems to me it's the same question. If the original sound had distortion, then let's get a system that reveals all. Not one that gets carried away and adds some more of its own.
Nuck.....?
All opinions allowed, here. We've fought before, and all now accept that we are all, um, "Strange".....? I got into a discussion about recordings and background music some months ago with a female friend of a friend who kindly told me that my argument was "bonkers". I am not sure that translates.
Best wishes! |
Gold Member Username: John_a
London
U.K.
Post Number: 4815
Registered: Dec-03
|
| Posted on Sunday, December 21, 2008 - 11:20 am: |
|
Update to Sept 30, above.
I obtained two JJ EL34s, one as replacement for the shot one, and one to keep as a spare.
So I tried a complete and working set of 4 x EL34s on the PLPL Two and it sounded fine at moderate volumes, but distortion crept in too soon on peaks.
So I replaced the 4 x EL34 with the original 4 x KT88 badged "Prima Luna". Distortion gone. Wonderful sound. KT88s go louder and that's about it. Any change in sound quality at same volume is below my threshold of awareness. With higher efficiency speakers than Quad ESL63, or ones less demanding of current, then I think one could save money and get the same result by replacing KT88 with EL34. Or buy a PLPL One in the first place. |
Platinum Member Username: Nuck
Post Number: 11292
Registered: Dec-04
|
| Posted on Sunday, December 21, 2008 - 11:52 am: |
|
John, the KT88's are going to play harder and hotter than the EL34's no doubt. Your amp has the plate voltage to run them, which is choice.
I like the fuzzy 34 sound, and my Svetlana's are pretty good. I have heard different stuff about JJ tubes, so I may be wary.
Good stuff John. |
Gold Member Username: John_a
London
U.K.
Post Number: 4817
Registered: Dec-03
|
| Posted on Sunday, December 21, 2008 - 04:41 pm: |
|
Thanks, Nuck. I maybe play music louder than some. I was just feeling immersed and happy when one of the folk next door knocked on the front door to ask me to turn it down.
The man I spoke to in the JJ supplier probably had it right - the EL34 is the original Mullard design, and the KT 88 is similar but tweaked to give as much power as can be from the same basic set-up. So the glass bottles are bigger. But the sound quality is the same at normal levels. I said "aren't the EL34s supposed to be warmer?" and he said "If you think that then you're halfway to comparing to sound of cables.." or words to that effect.
EL34:
http://www.sequoia.co.uk/shop/product.php?p=145
KT88:
http://www.sequoia.co.uk/shop/product.php?p=159 |
Platinum Member Username: Nuck
Post Number: 11297
Registered: Dec-04
|
| Posted on Sunday, December 21, 2008 - 05:15 pm: |
|
They changeout in some amps, John, but not my little one, no transformer for the current, and thats the difference. If the output amps run out of gas, then the voltage on the plate drops in a hurry, thats a fuzzy edge for 34's in a guitar amp, but thats where some players want it to be, and I have enjoyed the little amp here with Apollo source and Ling FRSD speakers.
If you can support the 88's, then I would likely play the same tubes.
I love 88's and the Svetlana's, again, are hard to beat, but thats all I have heard lately. |
Silver Member Username: Jazzman71
Phoenix,
AZ
USA
Post Number: 583
Registered: Dec-07
|
| Posted on Saturday, March 21, 2009 - 02:05 pm: |
|
Just replaced the EH KT88s in my Cary SLI-80 F1 integrated wtih SED "Winged C" 6550Cs due to a tube failure. The difference to me is striking to say the least. I will attempt to describe the main differences I hear, since they are now burned in for about 100 hours.
The detail is much better. I notice that I can focus on any particular instrument, regardless of relative volume to other players, and essentially hear every note clearly. Percussion is incredible--every brush, cymbal, rim shot, block, etc is just right there in the room, from the quietest to the loudest. The ECM recordings I have and use as reference (ECM discs to me are second to none in recording quality), are just beautifully reproduced.
I notice the sustain is improved. This may be related to above, and I'm not really sure how to define it, but I notice it more, especially in very quiet passages.
More space around the instruments.
Improved soundstage. More depth I think is probably the best way to describe it.
Very noticeably improved wrt just about every measure I can think of. And mind you this is with crappy Monster ICs and speaker cabling, which are obviously the next thing to go. I just have not decided on what cables to purchase, or whether to take a shot at making some. I am really looking forward to the improvements from better cabling.
These tubes seem to run a bit hotter than the EH KT88s, but are supposed to be he!! for stout, so we'll see. Biased on the low end of the 75-100 mA range spec'd for my amp, they deliver plenty of sound.
http://www.sed-usa.com/index.asp?strType=Content&strPage=6550C
Very, very satisfied. |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 13420
Registered: May-04
|
| Posted on Saturday, March 21, 2009 - 06:05 pm: |
|
.
Try running the bias up just a bit and listen for improvements. By choosing a hotter bias, the amp runs closer to a class A operation than a strict class AB. Increase the bias slowly listening for changes as you go. Do not over bias the tubes into cherry red plates.
. |
Platinum Member Username: Nuck
Post Number: 11880
Registered: Dec-04
|
| Posted on Sunday, March 22, 2009 - 07:26 am: |
|
Neil, what plate voltage are you running? |
Silver Member Username: Jazzman71
Phoenix,
AZ
USA
Post Number: 590
Registered: Dec-07
|
| Posted on Sunday, March 22, 2009 - 03:09 pm: |
|
Nuck, I think plate voltage is 450 assuming 117 VAC for the mains, but Cary manual leaves a lot to be desired.
JV, if the tube sticker says 62 mA bias and the amp manual says bias to 75-100 mA, which do you go by? |
Platinum Member Username: Nuck
Post Number: 11888
Registered: Dec-04
|
| Posted on Sunday, March 22, 2009 - 03:12 pm: |
|
Neil, go by the amp rating and go up from there.you might end up at 75 or more. Mind that the plate voltage remains stable as you bias up. |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 13423
Registered: May-04
|
| Posted on Sunday, March 22, 2009 - 09:01 pm: |
|
.
Yes, use the amplifier's bias setting, unless you have been told by the tube manufacturer or retailer the tube should be run "no hotter than ... ". Since you're unsure about this, I think it would be best to call the retailer and ask their opinion. You are unlikely to damage either the tube or the amp by running the bias at the minimum recommended by Cary, but why risk anything when a call will answer the questions you have?
. |
Silver Member Username: Jazzman71
Phoenix,
AZ
USA
Post Number: 591
Registered: Dec-07
|
| Posted on Sunday, March 22, 2009 - 11:11 pm: |
|
Nuck, I've pretty much followed the amp bias range. What I failed to do with the last set was to readjust the bias beyond the initial few weeks. That undoubtedly cost me some tube life as the bias probably needed adjusting as the tubes aged. Will follow up with the tube folks to make sure, which should be easy as the tube guy sold me the amp as well. Thanks to you both. |
Silver Member Username: Hawkbilly
Nova Scotia
Canada
Post Number: 545
Registered: Jul-07
|
| Posted on Monday, March 23, 2009 - 06:59 am: |
|
How did you end up deciding on that tube Neil ? Sounds like a great choice. |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 13424
Registered: May-04
|
| Posted on Monday, March 23, 2009 - 10:47 am: |
|
.
When adjusting bias keep in mind running the bias higher will result in the tube staying on just a bit longer and switching on a bit sooner in the push/pull cycle and result in a few extra watts. It will also decrease tube life, sometimes dramatically. Running the bias lower has the opposite effects.
. |
Silver Member Username: Jazzman71
Phoenix,
AZ
USA
Post Number: 596
Registered: Dec-07
|
| Posted on Saturday, March 28, 2009 - 12:56 am: |
|
CH, I read some on-line threads by people running the same or similar amps, and the guy who sold me the amp recommended it. It's nearly three times the cost of the EH KT88s, but wow what a difference.
JV, yes I'm generally aware of the bias impact on output and tube life. These tubes are supposedly tough, but I don't want to shell out another $200 in a couple of months for new ones. After checking following one of your previous posts, I learned that I should be shooting for 75-80 mA. I will be measuring it again a few days, and will see if it has drifted at all. I will also try pushing gradually up to 80 mA and see if I notice a difference. Thanks for the info. |
Gold Member Username: Exerciseguy
Brooklyn,
NY
United States
Post Number: 2528
Registered: Oct-04
|
| Posted on Sunday, April 19, 2009 - 06:42 pm: |
|
Any opinions? This amp seems to pack a lot of goods into a nice tidy package.
http://www.acoustic-dimension.com/pure%20sound/pure-sound-A30-integrated-amplifier.htm
http://cgi.ebay.com/Bewitch-6550-KT88-Russian-Tube-Integrated-Amplifier_W0QQitemZ200323996495QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item200323996495&_trksid=p3286.m20.l1116
Yeah, yeah, I know it's Chinese Gray-market, I don't think I'm buying, just looking.
 |
Platinum Member Username: Nuck
Post Number: 12114
Registered: Dec-04
|
| Posted on Sunday, April 19, 2009 - 07:35 pm: |
|
AUDIO Prädikat:
überragend, 100 Punkte, High End Klasse, 5 Ohren.
"Prachtvoll aufgebaut und bestückt, extrem feinsinniger, farbenreicher Klang"
What more could I add?
If there is warranty support, and the Alps and other parts are genuine, then this unit deserves a shot. |
Gold Member Username: Artk
Albany,
Oregon
USA
Post Number: 9445
Registered: Feb-05
|
| Posted on Sunday, April 19, 2009 - 08:19 pm: |
|
If you're shopping for a tube amp Christopher Agon seems to always have a supply of reasonably priced ones. |
Gold Member Username: Exerciseguy
Brooklyn,
NY
United States
Post Number: 2529
Registered: Oct-04
|
| Posted on Sunday, April 19, 2009 - 08:23 pm: |
|
How did you pick up your Yaqin? |
Gold Member Username: Exerciseguy
Brooklyn,
NY
United States
Post Number: 2530
Registered: Oct-04
|
| Posted on Sunday, April 19, 2009 - 08:35 pm: |
|
Just looking Art, this seems like a reasonably good deal, if all holds true.
The Pure Sound A30/Bewitched 6550 seem to be more widely available in the UK. |
Gold Member Username: Artk
Albany,
Oregon
USA
Post Number: 9447
Registered: Feb-05
|
| Posted on Sunday, April 19, 2009 - 08:50 pm: |
|
Hey...I have "One Tube" now...back in bizness! |
Gold Member Username: My_rantz
Australia
Post Number: 2160
Registered: Nov-05
|
| Posted on Sunday, April 19, 2009 - 10:40 pm: |
|
These Bewitch valve amps are often on Ebay here in Aus Chris. I read on a forum here sometime back that the buyer was very happy with his purchase and that it was well worth the money. The Yaquin seem very good value also. |
Silver Member Username: Jazzman71
Phoenix,
AZ
USA
Post Number: 662
Registered: Dec-07
|
| Posted on Monday, April 20, 2009 - 12:10 am: |
|
"If you're shopping for a tube amp Christopher Agon seems to always have a supply of reasonably priced ones."
PrimaLuna leaps to mind. |
Gold Member Username: Exerciseguy
Brooklyn,
NY
United States
Post Number: 2531
Registered: Oct-04
|
| Posted on Monday, April 20, 2009 - 02:49 pm: |
|
Yeah there are plenty of options out there, this Pure Sound/Bewitched just seemed to jump off the page at me as a good deal.
Buyers seemed to be pretty satisfied. |
Silver Member Username: Jazzman71
Phoenix,
AZ
USA
Post Number: 667
Registered: Dec-07
|
| Posted on Monday, April 20, 2009 - 11:20 pm: |
|
CM, I would check into the guts of the amp a little bit, as I did not find much info other than the glossy 1/2 page reviews. From what I saw, it seems like a good unit, but....caveat emptor. In that price range, I would look for soft start, point-to-point wiring, WBT, etc. That's why I sort of landed on the PrimaLuna. There's a Prologue One on A'gon for under a grand, and a recent one listed (SOLD) for $725. 35 wpc, EL34 output tubes, high quality build, seems like a fabulous amp for the money. No phono stage, but I don't believe the Bewitched has one either?? Just an opinion. Cheers. |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 13557
Registered: May-04
|
| Posted on Tuesday, May 05, 2009 - 12:15 am: |
|
.
http://web.archive.org/web/20050306024649/www.netaxs.com/~vkalia/beginner.html |
Gold Member Username: Stryvn
Wisconsin
Post Number: 1100
Registered: Dec-06
|
| Posted on Tuesday, May 05, 2009 - 07:02 am: |
|
Great link, Jan. Thanks |
Platinum Member Username: Nuck
Post Number: 12528
Registered: Dec-04
|
| Posted on Thursday, June 04, 2009 - 09:09 pm: |
|
Anybody can roll tubes, can you roll the stuff inside???
http://www.dailymotion.com/video/x3wrzo_fabrication-dune-lampe-triode_tec |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 13663
Registered: May-04
|
| Posted on Thursday, June 04, 2009 - 10:22 pm: |
|
.
I kept waiting for him to make one of those little glass unicorns. |
Platinum Member Username: Nuck
Post Number: 12535
Registered: Dec-04
|
| Posted on Thursday, June 04, 2009 - 10:24 pm: |
|
You didn't look for partez deux, he makes glass buttplugs. |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 13664
Registered: May-04
|
| Posted on Thursday, June 04, 2009 - 11:32 pm: |
|
.
Any EMT will tell you a Coke bottle works just as well - till it forms a vacuum and gets stuck.
. |
Gold Member Username: Dmitchell
Ottawa,
Ontario
Canada
Post Number: 2632
Registered: Feb-07
|
| Posted on Friday, June 05, 2009 - 10:27 pm: |
|
"glass buttplugs"?
That sounds like a recipe for disaster. Or at least a trip to the emergency room. |
Gold Member Username: Mike3
Wylie,
Tx
USA
Post Number: 2012
Registered: May-06
|
| Posted on Wednesday, June 24, 2009 - 10:42 pm: |
|
I just got one of my amps back from its return visit to the doc's office. I had a minor issue with not being able to run a 12AX7 for the splitter and had to us a 12AU7 in its slot temporarily. Then the other morning the amp developed a humming out of the right channel. Two caps the size of extra small Red Bull cans had to be replaced.
Now all I have to ask is how many of you have a neighborhood McIntosh qualified repairman who carries these in original McIntosh stock? Nothing like keeping the amp original! Then he only charged me for the parts, no labor, as he did not like it that I had to have a return visit even though these passed his initial tests about a month ago.
Peaks and slams abundant with Carlos Santana's guitars tonight!
A 1960's MAC amp in like new condition is a beauty to hear and behold.
Two of them, priceless! |
Platinum Member Username: Artk
Albany,
Oregon
USA
Post Number: 10061
Registered: Feb-05
|
| Posted on Wednesday, June 24, 2009 - 11:10 pm: |
|
Excellent Mike! We have a great Mac guy in Eugene, Oregon at the Stereo Workshop, Kevin. It appears your guy earned your respect. |
Gold Member Username: My_rantz
Australia
Post Number: 2262
Registered: Nov-05
|
| Posted on Wednesday, June 24, 2009 - 11:23 pm: |
|
Yep, it's great to have a "do right by you" service guy.
Good one Mike, enjoy those old fellas. |
Platinum Member Username: Nuck
Post Number: 12731
Registered: Dec-04
|
| Posted on Thursday, June 25, 2009 - 06:17 am: |
|
Thats a sweet repair, Mike!
So you are again running the higher gain 12AX7 in both? |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 13690
Registered: May-04
|
| Posted on Thursday, June 25, 2009 - 11:26 am: |
|
.
In the phase splitter position the tube has no relevant gain - it is run as a unity gain device (1 in = 1 out) and operates only to separate positive from negative waveforms and send them on their way to the appropriate circuits in a push-pull amplifier. You could run any 12 AX"?"/ECC83/5751 tube in this position but it's best to have both amps using the same tube brand and type since this tube is the first the signal passes through it does rather obviously affect the sound of the amp.
. |
Platinum Member Username: Nuck
Post Number: 12734
Registered: Dec-04
|
| Posted on Thursday, June 25, 2009 - 05:54 pm: |
|
Why would dry caps allow one tube type but not another?
Or did I miss the coorelation? |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 13691
Registered: May-04
|
| Posted on Thursday, June 25, 2009 - 08:38 pm: |
|
.
I don't think this problem had anything to do with the tube. The issue with the tube was a problem that occurred before MW had the amp serviced if I remember right. This problem occurred with the filter caps and as I understand it had nothing in particular to do with the tube.
The phase splitter is run as unity gain but if you put in a lower gain tube, you will not have true unity gain out. You can run any 12A"?" in that position but you won't necessarily get the same results if you run the wrong tube. The results will just not be as dramatic as if the wrong tube was used in a driver or pre amp stage.
My guess would be this amp's caps failed because it had sat for some time - possibly a few years - and when it was brought back up to power by the seller to check for operation it was just plugged in and hit with 120VAC. I think that's the story on this one amp. The other amp MW has had already been worked on when he bought it. This amp didn't work when we first plugged it in at Mike's and Les replaced all the coupling caps but not the supply or filter caps.
Is that right, Mike?
. |
Gold Member Username: Mike3
Wylie,
Tx
USA
Post Number: 2013
Registered: May-06
|
| Posted on Thursday, June 25, 2009 - 09:53 pm: |
|
Jan's description is spot on. While I am not getting a volume disparity with the 12AX7 back in place I heard enough of the 12AU7 that was substituting to say without a doubt, to my ears, there is more drive from the amp with the correct tube in the phase splitter socket. Certainly on the Kim Carnes LP I am currently spinning! |
Platinum Member Username: Nuck
Post Number: 12742
Registered: Dec-04
|
| Posted on Friday, June 26, 2009 - 09:49 am: |
|
So the splitter was getting a little 'loose' due to drainage from the caps? Maybe?
Running the same plate voltage for both tubes leaves the inductence/resistance of the 12A? tubes as the variable.
This could be very good info. |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 13692
Registered: May-04
|
| Posted on Friday, June 26, 2009 - 11:34 am: |
|
.
The variable is the designed in gain of the tube. The 12AX7 is spec'd as a 100mu while the 12AU7 is only 20mu. That is the rough spec and tubes vary from one to the next as far as how closely they stick to that spec with some falling slightly below to some a notch above.
Even though the phase splitter is not used as a gain device the circuit calls for a certain amount of voltage out of the tube. If you step that down at the front of the amplifier, nothing in the following circuits will perform at spec.
Consider the effect of stepping down a 1" water pipe to a 1/4" pipe and what happens at the output of the smaller pipe if you are feeding a series of sprinkler heads.
The amplifier won't sound bad with the lower gain tube in the circuit and the difference in a unity gain application would amount to a very small difference in actual output from the entire amp. Probably such a small difference the gain controls have more variance in their actual setings than would the output of the two tubes. But the amp would only perform as intended with the correct tube in place.
Running the wrong tube can also produce tonal differences in the amplifier. Quite a while back Kegger mentioned using 5751's as a step down tube with half the gain of a 12AX7 and while this application works, I pointed him to an article that mentioned how running lower or higher gain at any point in a circuit could possibly affect the tonal balance of the circuit.
Even back in the 1960's Mac was using tightly toleranced components - as low as 1% in some cases - to ensure their circuits worked as specified. Mac never warranted their amplifier's performance with tubes not provided by them. Inserting the incorrect value of any component at any point ensures the circuit will not operate as intended. If you were using a Dynaco tube amp with 20% tolerances in some locations, the wrong tube might not be as noticeable.
. |
Platinum Member Username: Nuck
Post Number: 12743
Registered: Dec-04
|
| Posted on Friday, June 26, 2009 - 03:14 pm: |
|
I remember Keggers issue, JV, but I recall that as being in a stereo amp, and not mono amps, which is a difference.
I am still lacking as to how a splitter tube would be affected by the caps and /or reverse.
In mono, the issue would sem to be simply pkase split, and I wonder which phase, + or -(ref) is affected?
I am taxing the issue, and have neither the smarts nor the inclination to advance the issue too far, but the splitter tube thing is interesting. |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 13693
Registered: May-04
|
| Posted on Friday, June 26, 2009 - 05:48 pm: |
|
.
First, these are stereo amps (MC240 = two channel amp at 40 watts per channel [as opposed to a MC40 which would be a true mono amp but still push-pull]) bridged to play in mono. Other than one side of the waveform being placed out of phase against the other side by the operation of the "mono" switch these amps operate just as they would in stereo.
(One of the old tricks was to connect a stereo amp out of phase at the input and then reverse the connection and restore phase at the outputs. This put less stress on the power supply and gave slightly better sound for cheaper amplifiers with lower quality supplies. The "mono" operation of this amplifier doesn't exactly accomplish the same thingt but the idea is the similar.)
Second, a push-pull amp still requires a phase splitter whether it's a mono or a stereo amplifier. Push-pull operates with the positive going waveform on one side of the channel and the negative going waveform on the other side. That's why there are two output tubes per channel in these amplifiers.
Two tubes per channel don't necessarily mean push-pull, you can have 2, 3 or more paralleled output tubes in a single ended amplifier. But the most typical arrangement would be one power tube for the "+" side of the right channel and one power tube for the "-" side of the right channel and then the duplicate of that tube compliment for the left channel.
With this arrangement the signal is immediately "split" from one poisitive/negative waveform into two distinct circuits and later recombined in the output transformers. Looking inside the amplifier you would see two channels, left and right, each with two identical circuits for "=" and "-" sides. So the signal path of the MC240 has four coupling caps of the same value and four bias circuits of the same value, etc.
http://www.kbapps.com/audio/schematics/tubeamps/mcintosh/mc240.html
If you look at the small signal tubes like the 12AX7/12AU7/12BH7 in this schematic, you'll see the pahse splitter 12AX7 and then each half of the channel is using half of the following dual triodes. A dual triode is essentially two tubes in one envelope with the ability to perform its duties to either two separate circuits, two separate channels or be paralleled as two tubes in one channel for higher gain and/or lower impedance. Not all designers use both sides of a dual triode, particularly in pre amps where the circuits are often run as single ended (and class A) so you sometimes throw away a tube that is good on its other half. Of course to use that half you would have to rewire the tube sockets.
The phase splitter was not affected by the capacitor failure. And the caps did not affect the phase splitter. These are two different issues with two different solutions.
. |
Platinum Member Username: Nuck
Post Number: 12750
Registered: Dec-04
|
| Posted on Friday, June 26, 2009 - 06:00 pm: |
|
Gotcha.
Good stuff. |
Gold Member Username: Kegger
Warren,
MICHIGAN
Post Number: 2780
Registered: Dec-03
|
| Posted on Friday, June 26, 2009 - 08:06 pm: |
|
Hey guy's what up?
Actually on the MC240 the first 12AX7 is not the phase splitter it is the voltage amp.
The phase splitter on this amp is the following 12AU7 in the LTP style arrangement.
The last 12AX7 is a buffer/follower to drive the outputs an really not the best choice
for this duty, a 12AT7 popped right in that spot "should" be a circuit upgrade.
The phase splitter is the critical part of the circuit in a push pull amp and the one that
needs there values properly arranged in the circuit to do it's job correctly so subs are
generally not suggested there. (also any direct coupled circuits can be tricky for subs)
The first 12AX7 with it's gain of 100, using a 5751 instead with it's gain of 70 should
end up being about the same gain with a 100K plate load on the 12AX7 and I would
gather a guess to it being a better sounding and performing tube in that spot as well.
Yep, it will perform differently then the original design and should alter the "sound" of
the amp, some will like the change an I'd assume some will not, never know till yu try.
Cheers,
Keg |
Gold Member Username: Kegger
Warren,
MICHIGAN
Post Number: 2781
Registered: Dec-03
|
| Posted on Friday, June 26, 2009 - 08:19 pm: |
|
Also not all phase splitters are unity gain, the LTP style gets about half the gain a tube
normally has in a straight single ended voltage amp type circuit, so it does have gain.. |
Platinum Member Username: Nuck
Post Number: 12757
Registered: Dec-04
|
| Posted on Friday, June 26, 2009 - 09:14 pm: |
|
Kegger!
The stories of your demise seen to have been premature.
Good post and quite timely. |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 13694
Registered: May-04
|
| Posted on Saturday, June 27, 2009 - 11:07 am: |
|
.
Kegger - Good to see you again.
I'm working from memory here as to the description I was given of the circuit almost 30 years ago but I seem to remember the first single 12AX7 being the splitter (and serving also as a buffer in that function). The 12AU7 then served as a phase inverter. That part I sort of remember coming straight from the Williamson design handbook and only later being bastardized by cheaper amps saving on tubes and combining functions.
But I don't remember this LTP style arrangement* you mention. I don't remember pin outs and I would stand a better chance of reading my high school French lesson book than remembering how to follow the schematic well enough to decipher this circuit - it has been 30 years since I used this information.
Can you provide a link or some information about the LPT arrangement?
Also why change the cathode follower to a lower gain tube? What's to gain there? Particularly since there are more good sounding 12AX7's then there are 12AT7's. NOS tubes might gain something (at the expense of something else) but the 12AX7 is still the go to tube for most of these purposes from what I remember and most especially in vintage designs.
And I think you and I will still disagree about the value of the 5751 in a circuit. I tend to think it would, as MW states about the 12AU7 in that socket, take away some of the drive of the amplifier's sound. Granted the 5751 and the 12AU7 are drastically different tubes but I tend to prefer the higher gain of the original. And then I thought the 5751 was half the gain of the 12AX7 and the 12AT7 was 70.
*LTP = Long tail pair? But that would couple this tube to the 12BH7 then, right? I didn't think you could place the phase splitter/inverter between the two devices.
It's been a long time since I actually had to remember this stuff.
Finally, what have you turned the Dyna's into this year?
. |
Gold Member Username: Kegger
Warren,
MICHIGAN
Post Number: 2782
Registered: Dec-03
|
| Posted on Saturday, June 27, 2009 - 12:02 pm: |
|
I'll post more later as we have 1 of our annual/monthly audio meets I'm leaving to shortly.
(we gather at a different members house once a month to have a few cocktails an audio)
Anywho on the MC240 schematic u linked, the input tube or first tube or driver is a 12ax7
and it just the first gain stage of the amp, if you look there is only one out coming from the
plate, no second or inverted it is just the straight grounded cathode voltage amp there in
which it drives the following stage which is the LTP splitter then through differential stage
to the follower.
Here is 2 links to talk of splitters and the Long Tailed Pair, LTP, on the 70's I use schmidt
type phase splitters which is a variant on the LTP.
http://www.angelfire.com/electronic/funwithtubes/Amp-Phase.html
http://www.bonavolta.ch/hobby/en/audio/split.htm
No the issues isn't gain with the 12ax7 being used on the last stage as a follower as there
really isn't any gain it's the plate resistance of the 12ax7 with leads to low current output an
high output impedance, 2 things that are not good for a follower and quite the opposite of
what they "are" good for, a 12at7 would do much better there in that regard.
Also I'm not the biggest fan of the 12ax7, both for it's eletrical properties and it's sound, I'd
much prefer using a 5751 where I "had" to use a 12ax7, but when I build or rebuild my own
I use low gain an low plate resistance tubes which yeild more current, tend to be a bit more
linear and require less feedback to get the job done, also I've found most to sound better.
Just not the 12AX7 fan here, not to say I don't use them I do in my phono stage or gear that
has them with no real easy or beneficial way to replace them. (just not my cup of tea though)
Not a 70 by any stretch of the imagination anymore (I do still have the 2 Jan, 1 orig 1 mod)
but here is a link to what I did using a 70's chassis to build a new amp on, only the PT used.
http://www.audiokarma.org/forums/showthread.php?t=208576
Lately I've been into Single Ended Ultra Linear, but I'm going to convert one/pair into push pull.
Cheers
Keg |
Gold Member Username: Kegger
Warren,
MICHIGAN
Post Number: 2783
Registered: Dec-03
|
| Posted on Saturday, June 27, 2009 - 12:04 pm: |
|
You can place the phase splitter pretty much anywhere in the circuit.
And most often placing it between 2 stages that are "steady" is a better place. |
Gold Member Username: Kegger
Warren,
MICHIGAN
Post Number: 2784
Registered: Dec-03
|
| Posted on Saturday, June 27, 2009 - 12:17 pm: |
|
12ax7 is 100mu, 5751 is 70mu and 12at7 is 60mu.
The big difference is in there plate resistances.
12ax7 is roughly 80,000
5751 is roughly 58,000
12at7 is roughly 13,000
So in a given circuit the 12at7 will garner more current, and quite often people don't realize
that you can get more gain from the 12at7 in a lot of curcuits from the sheer voltage that isn't
available to get the true 100mu out of a 12ax7 as the plate load should be say 300K or more
to do so but if you do that and set your cathode/bias resistor for decent current the plate volts
will end up way less 100 and loose all the gain you were hoping for with 12ax7.
Also quite often I find 12AX7's being used in circuits then all this feedback to knock the gain
back down to useable levels to where a low gain tube coulda been used in the first place with
less to no feedback being "needed" in the end.
Cheers,
Keg |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 13695
Registered: May-04
|
| Posted on Saturday, June 27, 2009 - 01:53 pm: |
|
.
"Paralell Single Ended Ultra linear"
Well, I recognize the chassis. But I don't think that's what Hafler had in mind.
OK, I get the parallel. But single ended UltraLinear?!!!
What's the point of that one?
. |
Gold Member Username: Kegger
Warren,
MICHIGAN
Post Number: 2785
Registered: Dec-03
|
| Posted on Sunday, June 28, 2009 - 06:28 am: |
|
You've got..
Push Pull Triode
Push Pull Pentode
and Push Pull Ultra Linear
I prefer Push Pull UL for the power portion, the easy supply verse pentode an the sound.
Well you have..
Single Ended Triode
Single Ended Pentode
So why not Single Ended Ultra Linear with all the same stated above attributes then I say.
With going Single Ended UL you get a very simple circuit that let's pentodes perform in
a single ended amp that doesn't have the typical overblown mids many find bothersome.
(quite a flat presentation from this type of amplifier layout but keep the SE "sweetness")
(And then obviously more power verse running triode strapped pentodes here to.)
Pretty much all new SE output transformers have UL taps on them these days for pentodes.
Some pentodes perform very very well in UL, and many are fine sounding in this config also.
Just another way of running the output section that has been getting more exploring as of late.
The Site DIYAUDIO has a tube section that can get rather creative at times with new things to
think about and ways of doing things, I do not agree with all of of it, but it is nice to see people
"thinking" and trying things not just rehashing the same thing over and over.
One thing I like and have been experimenting with is using LED's instead of cathode resistors
on driver or preamp tubes, no need for a cathode bypass cap and can be handy when your in
the need or want for full gain from the tube, the amp I linked to uses that and you can "roll" out
different ones with the sockets I installed on the driver board, you can use them to change the
operating point of the circuit with different voltages and current properties as well.
Cheers!
------
Nuck, good to see your still around, |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 13696
Registered: May-04
|
| Posted on Sunday, June 28, 2009 - 09:01 am: |
|
.
"Some pentodes perform very very well in UL, and many are fine sounding in this config also."
Is that what you meant to type? Yep! Pentodes have been performing well in UltraLinear since Hafler and crew introduced it in the late '50's. Most designers abandoned a simple pentode connection (and the Mac and Quad variations were available only under licenc) and more complicated) and we have seen virtually every new p-p tube amp with output transformers being done in UL for nearly 60 years.
"Pretty much all new SE output transformers have UL taps on them these days for pentodes."
That's almost too bad. I have less than favorable opinions of the ability to switch pentodes into triode or SE operation. UL was the point of combining the better qualities of pentodes and triodes. Beam power tubes IMO made both less desireable. I can't always agree with the idea of doing something just because you can do it. As a lesson that's fine but trying to build something the world has never seen and being successful at it are two very different things.
. |
Platinum Member Username: Nuck
Post Number: 12789
Registered: Dec-04
|
| Posted on Sunday, June 28, 2009 - 09:50 am: |
|
http://forum.ecoustics.com/bbs/messages/1/576374.html
This little flea amp from the Integrated thread is running the same arrangement, I think.
Seems to review pretty well.
And thank you Keg, still kicking here. |
Gold Member Username: Kegger
Warren,
MICHIGAN
Post Number: 2786
Registered: Dec-03
|
| Posted on Sunday, June 28, 2009 - 02:46 pm: |
|
Yes Jan not ALL pentodes work well in the UL config..
(and I'm quite aware it's been done for a long time and still by many)
Well I think you just haven't experienced enough pentodes running in SE then
as right now my favourite sounding amp is an SE pentode amp running in UL.
As I said some pentodes make excelent devices running in SE, be that there
Triode strapped or in UL mode, some are down right exceptional sounding.. |
Gold Member Username: Kegger
Warren,
MICHIGAN
Post Number: 2787
Registered: Dec-03
|
| Posted on Sunday, June 28, 2009 - 02:50 pm: |
|
It's not to say a SE output transformer that has a UL tap needs to be used with a pentode,
or that the pentode has to run in UL, you can use a triode with the output or strap the pentode.
Just that most new SE outputs provide the tap so you CAN run a pentode in UL if you want. |
Gold Member Username: Kegger
Warren,
MICHIGAN
Post Number: 2788
Registered: Dec-03
|
| Posted on Sunday, June 28, 2009 - 04:42 pm: |
|
Yah Nuck that little amp you linked to it does look like it is running Single Ended UL,
I can't find a good PDF on that pentode but I do think they are "streching" there stated
output power a bit there from what I can tell from tube "subs" that are out there like it. |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 13697
Registered: May-04
|
| Posted on Sunday, June 28, 2009 - 07:39 pm: |
|
.
"Well I think you just haven't experienced enough pentodes running in SE then
as right now my favourite sounding amp is an SE pentode amp running in UL."
Yep, I probably haven't experienced enough pentodes running in SE. I've not been impressed by the few I have heard. That doesn't comdemn the entire idea just because I haven't cared for two amps it just means I haven't been impressed by those two amps. I do, however, fail to see the point of the idea and maybe that's my stumbling block. Kinda like sticking a hopped up small block Chevy in a VW bug - I never saw the logic in that either.
Pentodes do one thing, SE does another.
(But send something down, I'd love to listen.)
I think you and I have always been after something a little different in our systems and the hobby. You like the smell of a hot soldering iron.
Since you've found tubes you've also found a liking for constructing things with tubes. That just never finally appealed to me. I stopped reading the DIY tube section a long time ago because I just couldn't get interested in what was happening there. No insult intended but there was a fair amount of mental m@sturbation when I last looked which was years ago and long before I sold you the Dynacos. Actually, that was partly why I sold you the Dynacos.
When I said I couldn't agree with doing something just because you could I was referring to this current trend towards creating a "sound" from your system and then switching that sound at a whim. That seems to be a big marketing trend right now and I am not much in favor of this for that and that for this. If you don't like pentodes for this album, switch to triodes. Don't like UL, switch to SE. I've always thought this was about establishing priorities, going after the music and not the equipment and knowing what got you where you wanted to be. This isn't, IMO, about whether you'd like more whipped cream on your Dianna Krall CD and less on your Led Zepplin reissue or how the amp soundstages.
That's where I've most often seen DIY heading over the decades I've been involved in this hobby. LIke you say, it's about making an amp "sound" a certain way. And the DIY'ers always have a different sound they're after. I don't want them to stop, I just am not interested in most of what I've seen come from the DIY crowd. Some items do make me sit up and think but many seem to be just exercises in what a particular tube or transformer can manage and then move on. Fun for some but not me.
I glad you're having fun, Kegger, you have even, from what I've seen, developed a bit of a reputation as a tube maven. But I can't get interested. When I hear about "more current" from a tube amp - and I've heard it for quite awhile now - I just think that's not what tubes do. Tubes do voltage well and speakers that want current aren't in the same market as tube are. Even "more current" within the amplifier I just can't get interested in. Maybe I'm just not understanding it as well as I used to. It seems more like the guy I heard at last week's show; he had spent 14 years "perfecting" his one speaker design. Geez, after about the eighth year I think I would have said maybe this isn't what I should be spending my time on.
(The local Lone Star show is mostly about DIY and I've been amazed at how differently people hear their own creations.)
Tubes do voltage exceptionally well and there are speakers that work exceptionally well with voltage, they just don't get placed into the mainstream much today because of the prevailing market where certain designers have moved the hobby in a particular direction. I read about Nelson Pass's designs and I think, "Now there's somebody who isn't doing something just because he can or because it will sell." That interests me. If I could ever convince myself to use transistors, I might try one of his designs - but then I'd probably have to change speakers since my speakers don't work on current supply.
I've been more interested in single drivers of late and I listened to a pair of field coil systems last weekend that I thought were impressive in many ways. So I'm kind of in my Dr. Harvey "Gizmo" Rosenberg phase. I have no intentions of giving up my Mac's because I still very much like what they do but what was old is new to me. (I really can't tell you how many times I seen DIY mods to the Mac amplifiers.) Again, IMO, the largest part of the hifi industry has been led down the wrong path for the sake of convenience and lower production cost. So my sentiments are with the DIY'ers, just ...
I don't know, are there old DIY'ers? I've always got the impression the constant change for the sake of change sooner or later wears off and you've seen most of this stuff before. I do think it's a hoot that you're doing your amp on a ST70 chassis. And I'm glad to hear you stilll have one stock.
So what are you doing with pre amps nowadays?
. |
Gold Member Username: Kegger
Warren,
MICHIGAN
Post Number: 2789
Registered: Dec-03
|
| Posted on Sunday, June 28, 2009 - 11:02 pm: |
|
I would agree Jan, you and I are different on many accounts, be it a "sound" were after
or tinkering or many other things, it doesn't mean we can't agree to disagree though.
(I'm certainly not trying to make anyone convert over to my beliefs, just expressing them
when I see or feel the need to chime in on a particular subject I believe in)
I think you know from the first we talked I was the kinda person who could never leave
well enough alone, and if it was good there must be some way to make it better then.
(I haven't changed since then and never will)
Also when I get into something I want to learn and try it all within my power, if my power
doesn't have the capability I try an learn what it will take to get there, that is my passion.
One thing you mentioned long ago was the old school tube sound an new school tube
sound, I believe a lot of that has to do with current I mention when running tubes, so at
the lower currents you get the old school and sometimes tuuby sound and new school
being more on the analytical side, I try an ride the fence on that one, maybe a bit more
current but less feedback, those are blanket statements an not always are true either.
I have my beliefs/feelings and biases about certain circuits and ways of doing things
as well, I'll look at something and feel well that isn't what I do and probably will sound
a certain way and not to my liking, sometimes that is true and sometimes it is not, so
I do 'TRY" and keep as open a mind as I can.
Tubes facinate me, I love how things go together and the construction process, there
is always something on my bench, I have a complete system there an listen to music
more there then in my main system.
I also get a lot of music in at our gatherings once a month on many different systems,
it is amazing sometimes the difference of oppinion on how well the systems play, an
I meen HUGE differences from the best I've heard to worst I've heard from people in
the same room listening at the same time. There is no one pleases all type setup.
(from great vintage to great new to DIY we have a pretty good group here)
I've got many different speakers, some I really really like the speaker and at times I
have matched or built amps ecspecially suited to there abilities, lately I've been at
the lower side of power so my speaker needs and wants change as well, my latest
is a 2-way 12" woofer (pioneer HPM 100) mated to a JBL waveguide running some
selenium compression drivers for some decent sensitivity and easy to drive.
(Another amp I feel is a great performer here is my Push Pull triode 6AV5)
Some call what I do not the right way to go about it, but I say if I can I want to try then.
(I have no problem failing, it certainly happens, that just makes me more determined)
A lot of people are not into the building or understanding, they just want there music,
I have no problem with that an in some ways wish I was the same, certainly would be
a few less headaches I'm sure..
There's a lot of new DIY tricks an fads I just don't buy into, but I feel I need to try them
as much as possible so I can say for myself whether they really do work or not though.
I've found some things I like, circuits I feel perform very well, a genre of tubes that do
what I want and tend to lean that way when I build or rebuild something. In Michigan
and the surrounding Ohio area there is a lot of well respected designers and DIY to
where I can and have learned a lot from, I am blessed in that regard for sure.
There are plenty of old Diyers and many well respected older "teachers" of the trade,
some have websites dedicated to it with very loyal followings, newer books written by
some of the greats from today and the past. (they are trying to keep it alive and well)
Yes I have my heavely modified ST-70, my stock ST-70, a chassis I got after a rebuild
for someone so I installed Acrosound TO-300 tranny's on an run 6BG6G sweep tubes!
Then the one you saw I got the chassis after a guy bought a new chrome one because
that one was so pitted and rusted, I had it sand blasted then I painted it to build an amp.
Preamp I'm working on at the moment is a plate choke loaded either 12B4 or EL86 in
triode using a tube regulator setting the supply voltage at a steady 150v B+, the plate
choke is basically a choke like you would have in a power supply but has the very high
Henry rating and takes the place of your plate load resistors, they are much less of the
DC resistance then your typical plate resistors so drop less voltage but get "full" gain.
(many feel using iron for plate loads in preamps is the road to best sound, we'll see)
I can't have just one system or even just 3 for that matter , I've got some single driver
stuff as well, I feel the intimacy of that approach is very addicting, those SE amps work
well with that combo to....What drivers or speakers are you messing with?
(Man that was a JAN sized post)
Cheers,
Keg |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 13698
Registered: May-04
|
| Posted on Monday, June 29, 2009 - 09:19 am: |
|
.
" ... there
is always something on my bench ... "
Yeah, I remember the pictures of your bench!
Link a few of the old timer DIY sites if you would. I'd be interested in seeing where the "hippies" I knew in DIY are at today.
You probably remember my contention that transformers went out of style because they were more expensive to produce and far more costly to ship across the ocean when Japan came calling with transistors. Yeah, I'd say chokes and transformers would be approriate for certain applications but they get costly very quickly if you want to do the job right. If you don't, then resistors and caps are better than a lousy transformer. I can't bring myself to say any sort of transformers are worse than direct coupling (even OTL's) but cheap output transformers are still cheap output transformers.
I don't know the 12B4. But this running pentodes in triode I don't get. It just doesn't make sense to me and seems like another fad that will pass - sorta like alkaline battery powered screwdrivers. Maybe in that same vein it will turn into something new but I'll wait and see. DIY always has fads IMO.
But how are we ever going to know without Billy Mays pitching it? That ain't gonna happen now.
I remember the discussions about old and new school, neither of which I felt was exactly right because they both went for a "sound" or at least could be classified with a type of sound. I still see a lot of people wanting a "tube sound". You can't remove yourself from "a sound" - unless you become a measurements tell us everything type of listener who has already convinced themself everything pretty much sounds the same then they hate "toobs" in the first place and tell me I'm stupid for liking those distortions they can measure.
Yeah, right. Enjoy your Pioneer receiver.
The show MW and I went to last weekend had a speaker builder exhibiting a cheapo system with an $89 Insignia receiver and a pair of Dayton kit speakers. He said it was just for fun to show how you could get "decent" sound for a few dollars. I really had to disagree with his assessment but I just exited the room and allowed him to go on thinking what he felt was good. He is right, they aren't plastic speakers that sound like cr@p and he admitted it wasn't hi-end but thought it served a purpose for his impoverished musician friends.
Maybe.
We all listen different and have different goals, I suspect the guy showing the 7'X4' electrostats hasn't spent a lot of time with a 300B lately.
I started out a couple years ago with a pair of Zigmahornets by Dave Merrill. Little 4" drivers that he designed and had custom built for him in small quantities. They have a pretty good reputation and I wanted to do a quarter wave system but needed something more than another 82-84dB system. There were too many Fostex systems around to build just another one of those and most of those drivers require some sort of baffle step to get rid of the rising mids. The Merrills sounded nice but the basic cabinets had too many resonances for my ears and didn't give the right spacial information. But with the Mac amps the mids were top notch and the high end tended to simply "exist". And the system did timing and pacing as well as any electrostat I've heard. Another member here had ordered a similar set of Dave's drivers and then decided he had too much going on in his life and wasn't going to build the systems so he sold me his drivers. I used those with my existing drivers to build a dipole quarter wave pipe using a configuration presented in AudioXpress a few years back, dropped the F3 down half an octave without giving up efficiency. Pretty simple stuff, use the basic TS parameters (finding them was the most difficult part since Merrill didn't supply any information) and read off the graph for the length of the pipe and start cutting MDF. After that its putting stuffing in and taking a little bit of stuffing out, putting in and taking out and phutzing with the port to get what you want. No coming in contact with 600+ volts, no wondering were that wire was supposed to go or how it touched the chassis and fried the wholedamnthing.
Merrill passed away a few months back but I see a new distributor has taken over his designs. I'll watch the stuff they do since Merrill's designs have such a good reputation and he was working on a new system when he passed away. I kind of have my eye on a quarter wave Lowther sometime but I have too many other expenses right now and I'm happy with what my system produces. I've liked the open baffles I've heard at the show the last two years. But I'm just not much into crossovers right now. I like the coherence of the SDFR's and have trouble warming up to most multi-ways.
I built a few subs but that's still just make the numbers match on paper and then check the distance from the fence to the saw blade. Tim Forman was on the forum a few years back and he gave me some information on a driver (that is also now discontinued and the company decided not to fight the politics/BS/insanity of people blowing your stuff up that goes with certain parts of DIY). So, if I get stupid with my system one night, I could be screwed big time since there are no more replacement drivers for most of my speakers.
I try not to be that stupid.
Is the pre amp line only or are you doing phono? Based on the Dyna's?
. |
Gold Member Username: Kegger
Warren,
MICHIGAN
Post Number: 2790
Registered: Dec-03
|
| Posted on Monday, June 29, 2009 - 04:55 pm: |
|
Yah the bench looks about the same as before, just maybe even mooore crap on it.
When I get a chance to dig up some of the old time diy sites I'll post them, there's a
guy John Broskie that I believe is an older gentleman that keps a running blog here.
http://www.tubecad.com/ (the tubecad journal) respects and refers to old designers.
Fullrange speaker without xover certainly is appealing, some work quite nicely aye?
Sounds like you've had/still have some experimenting going on there, glad to hear it.
I would also agree if your going use a piece of iron, ecspecially plopped right square
dab in the signal path I'd hope it to be a good one, and yah those plate chokes I have
are suppose to be pretty well made using some top quality construction materials to.
The 12B4 is a 9 pin triode with the gain of roughly 6 and plate resistance of less then
1k, so a straight single ended type circuit with no cathode followers and or feedback
are "needed" to get decent output impedance plus drive for the amp, the EL86 when
strapped triode is basically the same spec as the 12B4, same gain/plate resistance,
will draw roughly the same current an I believe only two pins are different so are easy
to swap into the circuit so I can try both. I've ran the EL86 triode strapped both as the
driver in an amp and as an output in another amp, I do like how they perform there.
The preamp is just linestage, I actually did some mods to my EAR 834P phono stage
a few years back (not my changes but the well documented thread on audio assylum)
and it is probably the one piece in my system I just leave alone, I feel to better it would
really take some time and effort, and I'm just plain happy with how it works with/on my
Denon table coupled to the Signet cartridges I've become fond of.
If I were to build a phono pre it would probably be based on that same design, maybe
use different tubes, right now it is an Amperex 12AT7 first stage, to a Mullard CV4004
(12AX7) for the RIAA to an RCA blakplate triple mica 5751 on the output. Works well.
I hear yu on not having backup parts for things you like, I try an have spares of any one
thing that get's serious play in one of my systems, (but I need even more room now) 
Not that your serious about doing speaker projects but the Partsexpess Woofertester
is a great tool that hooks to your pc then test any driver an it spits out the TS specs in
an easy to understand interface, it's like $100.00, what else is nice you can test whole
speaker systems or just test boxes to get impedance plots, quite handy for us toobies! |
Platinum Member Username: Insearchofbass
York,
Pennsylvania
Post Number: 11732
Registered: Jun-04
|
| Posted on Friday, July 03, 2009 - 10:04 pm: |
|
I would like to buy a decent tube amp to get my first introduction to them. Any suggestions? I have some 4 inch fostex speakers to try it on if need be. Model ss -1.1. |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 13995
Registered: May-04
|
| Posted on Sunday, October 04, 2009 - 11:22 am: |
|
.
Received this in an email the other day;
"Dear Music enthusiast:
We have acquired a quad matched set new old stock, original boxed RCA 7581A. This is equivalant to 6L6GC, 5881,KT66. The price is $399.97 for the quad set. Test conditions are: plate 400V grid -48 results 1) 22 ma, 2) 22 ma, 3) 21 ma, 4) 22 ma ma=miliamps
Another excellent offering for the more budget minded hobbyst are the Valve Art KT66 cryo grade tubes which are an exact copy of the GEC KT66. These are the best KT66 currently produced and are only 62.95/matched pair.
Thanks for your past business and check out our web site when you get a chance.
Ken Chait
WWW.TUBEMAN.COM"
. |
Silver Member Username: Hawkbilly
Nova Scotia
Canada
Post Number: 684
Registered: Jul-07
|
| Posted on Sunday, October 04, 2009 - 12:41 pm: |
|
I received a similar email Jan.
BTW, I recently changed did some tube changes in my amp and cdp. I replaced the Tungsram 6922's with some NOS Amperex in the cdp, and plopped in some NOS Sylvania EL84's in the amp to replace the Harma's that have been in there for over a year. I got them from Andy at VTS.
I particularly like what the Amperex's do in the cdp. If you've got a Minimax, it's an excellent combination to try, and the price wasn't crazy....I think around $150 for the pair. |
Platinum Member Username: Nuck
Post Number: 13633
Registered: Dec-04
|
| Posted on Sunday, October 04, 2009 - 01:02 pm: |
|
Sidebar...
Some people would just die if they heard $150 for a pair of tubes for hifi.
But they have receivers, so...
$400.00 for a quad?
Is this a fair price for this set for a stereo amp?
6L6's are usually used in quad's in monoblock amps, yes? |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 13997
Registered: May-04
|
| Posted on Sunday, October 04, 2009 - 05:07 pm: |
|
.
Overall, the Amperex 6922's are probably the best of the bunch though there are a lot of varieties of Amperex 6922's and their sound might not suit some systems. A while back I acquired a set of Amperex 6922's for my AI pre amp to replace some Sylvanias I had been running in the phono side. I had a set of Amperex 6922's that were NOS when I bought them in the early '80's. I got them then for $20 per pair and they now sell for about $200+ per pair. There is a difference in the two Amperex tubes but the most recent additions better fit my current system than do the Sylvanias.
The tubes advertised aren't 6L6's. They are 7581A's which is an "equivalent" to a 6L6. Different applications though most would be drop in replacements. You need to check the bias current and plate voltage on your amp, the suggestions for the tube's preference which can be determined by the transformers capacity and the plate voltage and current the prospective tube sounds best at vs. the ideal tube for your amp. This tube might produce higher or lower output than another similar tube so "equivalent" is with some cautions.
You should be able to buy a very nice set of new Svetlana Winged "C"' 6L6's for about $120 USD for a quad set, lesser tubes for a few dollars lower priced. They aren't NOS but they are 6L6's which is the "kinkless" equivalent to the British KT66. The GEC KT66 was a very nice sounding tube.
If your amp has fixed or auto bias set up, you don't require a matched set if you're just replacing an existing tube or tubes.
For NOS RCA's $400 is not bad.
If the amp were a push pull monoblock, it might require two tubes per amplifier. Depending on the manufacturer two 6L6's in pp would get you somewhere between 30 - 55 watts with 55 watts being a very hard (and hot) drive on the tubes which would reduce their lifespan. The more tubes wired in parallel, the higher the output power.
. |
Platinum Member Username: Nuck
Post Number: 13638
Registered: Dec-04
|
| Posted on Sunday, October 04, 2009 - 06:29 pm: |
|
Test conditions are: plate 400V grid -48 results 1) 22 ma, 2) 22 ma, 3) 21 ma, 4) 22 ma ma=miliamps
400 on the plate must be getting these tubes pretty hot indeed? |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 14000
Registered: May-04
|
| Posted on Sunday, October 04, 2009 - 07:13 pm: |
|
.
Depends on how you're using the tube and what tube you're using. 600V would be very hot and beyond anything I know a 6L6 can withstand for long. 550V would be hot and still beyond most 6L6's if you want long life. 420-500V would be average I'd say and well within the limits of any 6L6 tube and good for a push pull class AB amp.
Using an "equivalent" tube is sometimes due to the tube's specs and what it was designed to do and for whom. In the US most of the numerical designations such as 5771 and so on are originally military spec tubes that would likely have somewhat different specs than the 6L6 variety or the KT's. However, people buy the military tubes thinking they must be better tubes and often they do not perform as well as the audio tube due to the specifics of what the military tube was meant to do. One more reason the "sound" of any specific tube is circuit and tube dependent.
The question with higher voltages becomes the quality of the ps and the power transformer.
Bias voltage would be more a factor in power output and tube life. -48VDC is average for an adjustable bias configuration if I remember right and should be on the low side of the tube's potential. The 240's run -55VDC in a fixed bias mode and run cool at idle.
http://www.guitaramplifierblueprinting.com/Tube/6L6GC-svet.pdf
http://www.tube.be/6l6.html
http://www.guitaramplifierblueprinting.com/datasheets.html
If Kegger stops by, he should have better information though I don't think he has done much with 6L6's - they tend not to be the tube many people use now days in audio, they lack the power grunt of a 6550, the sweetness of an EL34 and the faddishness of an EL84. They are still the favorite of a lot of people with both guitar and hifi amps though, VTL used to do a lot with the 6L6 and the KT66 is a European favorite for its highly musical sound. Find a guitar player with a beat up blues amp and it will probably have 6L6's in it; http://www.guitaramplifierblueprinting.com/files/Blues_Deluxe_Schematic.pdf.
. |
Gold Member Username: Exerciseguy
Fort Hamilton,
NY
United States
Post Number: 3046
Registered: Oct-04
|
| Posted on Sunday, November 08, 2009 - 09:33 pm: |
|
http://www.unplggd.com/unplggd/product-review/product-realview-acoustic-research-av100b-tabletop-radio-with-ipod-docking-station-066058
 |
Gold Member Username: Exerciseguy
Fort Hamilton,
NY
United States
Post Number: 3047
Registered: Oct-04
|
| Posted on Sunday, November 08, 2009 - 10:50 pm: |
|
...I wonder if you can bypass the internal speakers and use it to fire-up some external ones? 10WPC ain't too shabby? |
Silver Member Username: Hawkbilly
Nova Scotia
Canada
Post Number: 797
Registered: Jul-07
|
| Posted on Thursday, February 04, 2010 - 04:28 pm: |
|
http://homepage.mac.com/tlinespeakers/vaughn/downloads/SE-v-PP-Part1.pdf
Thought I'd post a link to this article. Probably not particularly informative to some of the seasoned tubeheads here, but I found it one of the best and well written articles on basic tube amp design that I have read. Eddie Vaughn has a very loyal following for his amps. |
Platinum Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 14478
Registered: May-04
|
| Posted on Saturday, February 06, 2010 - 03:42 pm: |
|
.
That's a fairly good article, CH. It would be a good primer even for those interested only in solid state gear. It's well worth the time it takes to read.
I do detect a patisanship in the writing but overall for an eleven page document it covers the bases well and clears up some of the often times confusing details of construction between a SE and PP amplifier. Terminology which might be encountered in any discussion of the two topologies is covered in sufficient detail to provide a groundwork for understanding how the amps might be explained by a more evangelical retailer.
It has a good beat and you can dance to it. I'd give it a 4.
I take minor amounts of objection to only a few conclusions drawn by the author. The first of which is the line; "Human psychoacoustics do not obey the laws of science very often!" Not that I absolutely disagree with the statement, it is an idea most experienced listeners should be able to agree with on principle if not from actual experience. It's just that I find such statements to be open screen doors to those individuals who simply do not care to understand which laws of science are being somewhat disobeyed. The article's final quotation from van der Veen is too often abused by such individuals as a permission to ignore the most basic of rules for how we get from live performer to perceived reproduction. IMO it is a shame the attitude "My ears telll me everything I need to know" has been allowed to fester in the audio community for it is all too often those who do not even understand how "their ears" perform their assigned function who then hide behind the words of those who best understood just how to use their rational mind.
Secondly, I would say the article gives short shrift to well designed, classic and enduring alternatives to the simple SE vs. PP debates. Vaughn appears rather derisive of the Golden Age tube designs and of those who built upon their foundations without at all explaining the circumstances they were attempting to overcome. His absolute dismissal of "specs" is discouraging for the reasons mentioned above. To say the debate is strictly between SE and PP amplifiers is too simple and factually incomplete. Not mentioning UltraLinear, Unity Coupled or Current Dumping amplifiers designed by (ostensibly) Hafler, McIntosh and Walker is the equivalent of not mentioning De Forest or Tesla at all - all of whom the author did not mention at all.
It is a short ten page article and it packs a good bit of information in those ten pages. My only wish would have been that the author would have provided a more clear path to follow towards the next argument(s) regarding tube amplifiers and that his partisanship for a particular topology would have been reined in somewhat more than he managed. However, he is selling a SE amplifier on his site so there is only so much one can expect I suppose. The Chevy salesman doesn't recommend a Honda.
I would also suggest everyone read the article on damping factor found on Vaughn's site. His "links" page is also filled with plenty of informative sites.
Thanks, CH.
. |
Silver Member Username: Hawkbilly
Nova Scotia
Canada
Post Number: 800
Registered: Jul-07
|
| Posted on Saturday, February 06, 2010 - 05:33 pm: |
|
Yeah, I thought he covered the basics very well....enough to help me understand some of the basic building blocks better than I had. There is some interesting differences between his views, and that of say Steve Deckert. I doubt you'll find two designers to agree on everything, but I always find it interesting to see what is agreed on, and what isn't. As you point out, you always have to be aware of what the author is selling, as that may lead you to his prejudices. |
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