I need help trying to resolve this issue. I have a old Adcom GFA 535 2 ch Amp running my surround speakers. It is a older amp, but sounds good, and was cheap at the time when I needed a 2nd amp. When changing channels on cable, if it goes out of DD, or during a startup of a movie, when it is switching between stereo, to DD or one of the various surround formats, it makes a popping sound through the surround speakers. It also does this at power up and power down. My 3 ch amp for my mains does not do this (Monster Power MPA 3250). Is there anything that can be added for low cash outlay that can get rid of this, or would I be better suited to buy a new amp. If I need another amp, are there any to stay away from that have the popping noise. I have been looking at a Rotel RB-1050 or a couple Outlaw monoblocks, but I really don't need that much power for my small surrounds. Any ideas?

bump

I have had a similar ongoing problem with my 4 yr old Onkyo amp but only on my sub channel. Every time the surround mode changes (menu changes and layer changes on DVD's, channel changes on my STB, etc) I get a thump thru my sub (Axiom EP-500). I believe that some of the older Onkyo amps have a problem with their muting software and that is is the source of the problem. Your problem may be something similar but is showing up with your surround speakers.

My only solution is to turn the amp on my sub down until I start a DVD and I know the surround mode won't change. Once the movie starts I have zero issues until I hit a layer change and I get the thump again. I usually turn my sub volume down for TV watching anyway so no big deal there.

Very few people complain of this problem (I think if you do a search there is an archived thread with some more info on this problem) so I suspect these issues have been corrected in the new amps and receivers.