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

On the off-handed chance this may help....a few years ago I found the source of a buzz in my system thru luck. The system was completely ground-floated except for the tube preamp and, at higher volumes with no source signal, it was very clear - annoying bzzzz. After trying quite a few things, I grabbed the metal rack to support myself and moved to the back of the preamp to take another look and touched the case. No, no shock! Just no buzz. It completely disappeared! I wound up taking a lead from the pre's grounding post to a connection on the rack and have been happy ever since....well, except for that tweaking stuff! Good Luck!

This was the very problem that I had for 8 months. I tried everything. I finally found the problem when I replaced a pair of RCA intercon that had one bad connector.

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.

I am going to assume the crossover frequency was higher before? I am going to take a guess that you have a bad filter cap in the power supply. I base my conclusion on the following: your woofer has a better low frequency response then your higher frequency drivers so when you switched your crossover to 80 Hz the signal was attenuated. I also assume you have a full wave rectifier where the ripple is at 120Hz and would sound more like a buzz then 60 Hz hum. If you have a good old VOM (non digital volt-ohm meter) you can do some rough checks. You can disconnect one end of the filter capacitors (after they have had enough time to discharge) and on the R x 1 scale [lace the leads across the capacitor the needle should move to the right very quickly toward 0 ohms and slowly move to the left toward infinity. If one of the capacitors does not do this this it is probably bad. What you are doing is simulating putting DC power across the capacitor. Whena capacitor is fully discharged it should look like a short hence the meter move toward 0 ohms. As the capacitor charges it looks more and more like an open circuit hence the meter moving toward infinity. I hope this helps as I have made some assumptions.

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.