Did anyone manage to ``repare'' a buzz, ever?

Thanks Sean for your reply. I actually tried all those things you mentioned (and some more) with the help of the comments I found in this forum. Even with everything completely disconnected except for a preamp, power amp plugged into the wall (or into the power conditioner) and just one interconnect between them (also tried different ICs, power cords, power amps) the buzz is stil there. It is not volume sensitive and does not go to the sub speaker when the 80hz crossover is engaged (but it is there if not). So, I am at the stage where I am seriously consider to go to a repair (Sorry Subaruguru) shop and wonder if this helped someone, ever.

Many thanks to all the participants of this forum. I am trying to use all your help and have some answers and more questions to ask.

Ktsteamer:

It is an interesting possiblity. I indeed have the room's lighting on a dimmer switch in a different room, which is exactly above the listening room. In my experiments, I made sure that it is swithched off, but I wonder if, even so, it may still creat a buzz???

Mzn50: I plug them all into one power surge protector and
line conditioner. I tried the cheater and checked the polarity too. I also connected the chassis of the preamp to other various components. The crossover I mentioned is in the separate power amp for the sub, that is, not in the preamp in question. So, I can run the full range signal from the preout in the preamp, and then can cut it off below 80hz, by engaging the sub amp crossover. This kills the buzz in the subwoofer speaker. Hence, it is not a 60hz ground loop hum?

Thanks.

I manage to reduce my ``buzz'' plugging these cheap 5-cents IC's into the unused RCA input sockets. (I cut the connectors off and isolated their wires first.) I found this ``recipe'' in the forum discussing those Cardas caps (well, they seem do not help but look just great). This method does not kill the buzz but made it somehow much less annoying and not that loud. How long I can live with this remains to be seen though. Thanks again for all your help.

Liguy:

Thanks very much, but unfortunatelly I am not that capable technically to be able to follow your suggestions.
You might be right about the problem. I may use it if I find someone who can help me. So far I use these home-made caps, which are sort of helpfull and provide so far a relief. Maybe, the buzz is due to some RF noise? Can it be consistent with your comments?

About the assumption: I can run a full range signal through the subwoofer amp or engage the low pass filter at 75hz. When I have it full range, I have the same buzz in the sub
speakers (taht is, amplified by the separate sub amp) as in the other speakers amplified by their amp. When I engage the low pass 75hz filter, the buzz disapperas from the sub speakers.