Need Help With a Problem in my Surround System

First: some background info.

I have a pair of B&W 804 Nautilus Speakers for my fronts. They were an upgrade and completely overwhelmed my Yamaha RX-V1000 Surround Receiver so I power them off a MacCormack DNA 125 Amp and then run them back through the Yamaha. My rears are smaller B&W DM 603's and they run directly off the Yamaha. I have a Nautilus HTM 2 Center and a Velodyne sub. My stereo is a completely separate system in the same room.
Yes- it is crowded.

Anyway I am watching a ballgame on my surround system last night with the sound muted and listening to records on my stereo. You might ask why not just leave the surround receiver off rather than muted if I am listening to a completely different system. I don't completely understand the way it works but in order to set up my TV so that the score of the ballgame at the top of the screen doesn't not get clipped off I need to run the receiver. If I was watching say, a movie with no sound I could just leave the receiver off
But I digress...

Anyway, I was changing the record when I noticed a buzz coming from one of my B&W' fronts even though it was muted. I went over to the other speaker and there was nothing. No buzz, no nothing. I reved up that system and the buzz speaker sounded OK, the other one: still nothing. Fearing that I had roached a very expensive speaker by blasting the "Springsteen Live at Madison Square.." DVD one time too many, I switched the speakers and was releived to find that problem remained on the right side. So my speakers are OK but now what?

I now figure my problem is either in the Yamaha Surround Receiver, The MacCormack power amp or in a connection. Any suggestion how to trace it from there? Of course all this stuff is nicely racked and not easily accessed. I appreciate any advice since I am not much of a nuts and bolts guy.

Thanks!

Peace-
Norm

 

Norm, disconnect the cables between the right and left speakers and swap them with each other and see if the problem's still there. If it's still there on the right side you know it's not the cables. Then disconnect the MacCormack from the chain to see if the problem goes away. If so, you've found your problem . If not hook it back up and if you can, take the Yamaha out of the chain to see if it is the problem. If it's still there you put the Yamaha back in and start checking all inter-connects by switching left and right, and when and if the problem ever changes speakers you know you've solved your problem and can replace the damaged cable.

You might have to check everything that's plugged into your pre-amp/receiver via RCA cable, but you will find the problem this way or does it only happen during TV?

 

Hey Dave:

It's happening during TV, DVD..everything.

When I switched the speakers the buzz was still on the left and the "dead" side remained on the right. Then I killed the MacCormack and the buzz stopped. I had been keeping that amp on all the time. I am starting to think that box may be the culprit. Actually the MacCormack factory is not far from me. I may just drop off that amp and let them clean it up and test it out.

Still you have a valid point about the cables and I was frankly ashamed by just how crappy they are anyway. I have wonderful interconnects and speaker wire on my stereo but much of what's behind the surround system is the same junk the install guy gave me three and a half years ago.

There's just so much stuff back there that you can barley move. I have a DirecTV Hi Def receiver plus a lead to a roof antenna and with six speakers, amp, receiver, Monster Box, VCR, and DVD player it's a nightmare. Plus the speakers from my stereo run to my "TV Wall" as well.

Still I just listened to Steve's CCR "WATPB" LP and it sounds amazing.
I must be doing something right

Peace-
Norm

 

often there are extra noises when the tv and the hi fi are connected.
ideas:
disconnect the tv from the yamaha (s video, rcas etc)
turn the plug on the MacCormack around
(check the voltage on the chassis of the MacCormack to ground and reverse the plug and see if the voltage drops. the lower the better and less chance of a buzz.
If it has been HOT - try a fan on the amps
look around for NEW electrical stuff on the circuit. microwave, new refrig,
check for changed location of power cords - did one get placed on top of a speaker wire.
loose speaker wire
check for buzz with sub turned off
Taking the amp in is probably the lowest stress thing to do.

 

Yeah, you just have to approach the whole "what the heck is that?" scenario with a back-wards analysis and then follow it until you've isolated the problem. Sometimes a pain in the ****, but the solution is always a little extra gratifying when you figure it out for yourself and even more so when you can repair it when its nothing major. Sounds like you already know it's the McCormack. Let us know the out-come.

 

It was the MacCormack after all. I pulled the fronts off the MacCormack and ran them directly off the Yamaha and they worked fine. Interestingly MacCormack's factory is in Northern VA not far from the pharmacy. I called them but they are closed on weekends.
Guess I will try to run it up there this week. I have been leaving that amp running all the time. I need to ask them if that's a good idea; it's only three years old max. Thanks for the advice

Peace-
Norm

 

Actually each system runs off a dedicated circuit. One of the smarter things I did down there I think...

Best-
Norm