So while I was waiting to hear back from Joe, I went ahead and started removing some of the 15 opamps ic's. Eureka! When I got to U9 a CA3080 intersil I found the distored noise went away completely. Luckily I had one. Replaced it and now this thing sounds awesome. Thanks again Joe for all your help. She is going for sale now, which will make my wife happy and our condo less cluttered. Cheers.

 

Robert,

All you would have to do is stick the spectrum analyzer near the speaker and inject a single tone into the input. You should see that tone. Lets say you fed a 400 Hz tone, the second harmonic is 2 x the fundamental frequency or 2 times 400. you might not see the 800 Hz tone or any even harmonic tone depending on the configuration. You could see the odd harmonics 3, 5, 7. etc. 3 x 400 is 1200 Hz. That tone should be much lower than the fundamental 400 hz. In fact the scale is probably in decibels. You would expect the third harmonic to be more than 60 dB down.

It's good you got the amp repaired. While your waiting for the sale, or you have a smaller amplifier you can play with, take your test setups for a drive .... play with them. For instance, if you see 60 Hz or 120 Hz ... or possibly 180 Hz, you know they could be caused by power supply problems as the mains here in the US is 60 Hz. You normally can hear those problems. The frequency can guide you on where you can start your troubleshooting search.