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Thread: AMP clips - why? help! |
    
New member Username: Zman1
Post Number: 1
Registered: Dec-05
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| Posted on Wednesday, December 21, 2005 - 06:27 pm: |
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Hi,
I have a marantz sr5300 amp. 6.1 channel with 90 rms. i purchased a set of dreamm 77 speakers from ebay. 250 watts fronts, 150 watts rear & centre. Both the speakers and amp are 8 Ohms.
Currently the amp clips at random volume levels. Mainly its up near high end around 3/4 of what the amp can function at. I dont know why i am having this problem.
I have checked the set up on the amp to ensure that the correct sizing has been selected for the speakers. Dont know what else to try. Maybe the amp isnt powerful enough to run these speakers?
Any ideas would be welcomed.
Thanks |
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Gold Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 6975
Registered: May-04
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| Posted on Wednesday, December 21, 2005 - 07:23 pm: |
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1) The "wattage" of the speakers is meaningless. Speakers don't got no watts.
2) An amp will clip at various levels depending on the signal it is fed. Some devices such as CD players have a higher output voltage (and hence a higher input voltage going to the amplifier) and will cause the amp to clip at a lower position on the volume control than would a signal of lower input voltage. The volume control is not meant to be run at full crank. It allows extra room for those lower voltage signals. Music with heavy bass eats up more power than music with no bass. Take all of these into consideration and the answer is probably going to be; when you hear distortion turn down the volume.
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New member Username: Zman1
Post Number: 2
Registered: Dec-05
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| Posted on Wednesday, December 21, 2005 - 07:45 pm: |
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First of all thank you for the response.
Two things. The volume control has never been set to full crank and the sound has never been distorted that i had needed to turn the volume down. Even just simple easy listening has caused the amp to clip. Would an amp with a higher RMS output help?
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Bronze Member Username: Nadz
California
Post Number: 18
Registered: Aug-05
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| Posted on Thursday, December 22, 2005 - 01:13 am: |
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Tell us more about the speakers. Do you have a link ?
How big is the listening space ?
Speakers with big impeadance swings can be tough on receivers. Just because its rated at 8 ohms does not mean it stays there. For all we know the speakers could dip to 3 and 4 ohms. What is the sensitivity of the speakers as well ?
Also keep in mind that the Marantz only puts out 90 watts into 2 channels driven at the same time with full bandwidth. It will deliver 90 watts into all the channels just not at the same time. If you did an all channels driven test you would end up with only about 40 to 50 watts.
The only receiver companies I can think of that quote "all channels driven specs" are NAD and Rotel. There are a couple other companies that do all channels driven ratings as well. Just forgetting there names right now. |
Gold Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 6982
Registered: May-04
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| Posted on Thursday, December 22, 2005 - 11:58 am: |
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" ... the sound has never been distorted that i had needed to turn the volume down."
You've confused me. What do you consider "clipping"? To most people it is the amplifier running out of available power and "clipping" off the top of the waveform. This produces ever increasing amounts of harmonic distortion. Therefore, if your amp is clipping, it is distorting the signal.
Maybe an explanation of, "Currently the amp clips at random volume levels. Mainly its up near high end around 3/4 of what the amp can function at", would help me. How are you determining what the amp is capable of if not when it clips the output?
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New member Username: Zman1
Post Number: 3
Registered: Dec-05
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| Posted on Thursday, December 22, 2005 - 05:21 pm: |
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Hi Guys,
NADz - here is a link that you can view the speakers on that has specifications as well
http://cgi.ebay.com.au/DREAM-ACOUSTICS-ABSOLUTELY-HIGH-END-DREAM-77-SPEAKERS_W0Q QitemZ5838239540QQcategoryZ14993QQcmdZViewItem
Jan.. Excuse my descriptions but my definition of 'clipping' is that the amplifier cuts off and jumps to stand-by mode.. i.e. It doesnt really matter what level the volume is set at, the amp will clip (jump into standby mode) leaving the DVD player on and no sound coming out of the speakers.
I need to get to the bottom of this.. i appreciate ur feedback.
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Silver Member Username: Nuck
Parkhill,
Ontario
Canada
Post Number: 765
Registered: Dec-04
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| Posted on Thursday, December 22, 2005 - 05:43 pm: |
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Joey, that is shutting down for protection.
Do all channels go silent? Any little lights come on when it happens?
You have a short in your speaker wires somewhere.
Disconnect one channel at a time, and continue testing(at low volume) whilst wiggling the speaker wires. |
New member Username: Zman1
Post Number: 4
Registered: Dec-05
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| Posted on Thursday, December 22, 2005 - 06:20 pm: |
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Nuck, yeah the amp is definately shutting down for protection.. all channels go silent, but no lights come on when it happens. (actually not that i have noticed)
I'm thinking a short in the speaker wires also. I will try disconnecting the speakers one by one at the amp end and see if that makes a difference. If not i would think that points to the amp itself.
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Silver Member Username: Nuck
Parkhill,
Ontario
Canada
Post Number: 766
Registered: Dec-04
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| Posted on Thursday, December 22, 2005 - 06:29 pm: |
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Joey, do the wiggle test on the wires, and a 'knock' test at the connects of the receiver as well.Knock, knock.
I find all sorts of stuff wiggling and knocking.
Good luck! |
New member Username: Zman1
Post Number: 5
Registered: Dec-05
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| Posted on Thursday, December 22, 2005 - 06:41 pm: |
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thanks pal.. i will advise.
might be a few days though.
appreciate the help |
