Hi. I am sure this has been covered, but I couldn't find a thread that 'splained it to me in terms I can understand (IQ=shoe size). I have a solid state audio amp that has a noticeable buzz/hum in the output. After several tests I have eliminated any ground loop. Sounds like 60hz but I put it on the scope and it appears to be a very dirty signal a little closer to 70hz (???!!!). Today, I placed a DVM across the DC output legs directly after the filter caps (pretty much standard set up: AC in to transformers, then to bridge rectifiers, then to filter caps out to the signal boards). The DC readings are fine, but I am still getting about 0.1 VAC. Does that sound acceptable? I thought that there would be far less - even nondetectable - AC at that point. The bridges are brand new as are the caps. This is my first time trying this and am in learning mode. Any and all thoughts are appreciated. Thanks.