Geeez, Tommy, it just doesn't make sense that they are humming at only 120 volts. If it weren't for the fact that both are doing the same thing I would think it was something mechanical.
I don't know much about the audiophile line conditioners. I did look up a couple of brands on the internect in response to a post someone had made. It said something like "No capacitors, no inductors, no transformers to interfer with the purity of the sound!". It cost 6 or 7 hundred dollars and they were advertising that there was nothing useful in the box?! The ferroresonant transformer I mentioned won't help because the line voltage is not too high.
The diodes are like little valves. One is pointed in each direction because AC needs to go both ways. It takes .6 volts to open the valve. ten pairs would give you a 6 volt drop. So, you just make some more pairs and put them in series with the one you have. They can be soldered to the one you have. They can go anywhere in either leg and will work the same, just not in parallel with each other. You could just temporalily cobble it all together with alligator leads to see if it helps before taking the time to do it right.
I'm not familiar with the amps. Is the manufacturer available for advice?
