So before the power conditioner arrived (last night) I did some testing and adjusting with the two Vidar’s. The buzzing sound is faint but I could hear it while standing near it, or in my sitting position if the environment was quiet enough.
I took the the amps out and tried the stock power cable, the thick chonky Pangea cable I use with them, different power strips, different outlets, different circuits, plugged directly in or through power strips and still heard the same buzzing. Also, I disconnected the speakers and the preamp.
I moved the amps back and forth and side to side in the rack and I noticed a change in the sound of the buzzing. In some positions it got quieter, and others no louder than I have been experiencing.
What I’ve determined is that the buzzing is just a part of the normal operation of these amps, and like I mentioned, it’s very low and quiet. So I what I figured out was that the last time I rearranged the rack, the shelves and whatnot, I moved the amps from the bottom shelf to the one above it, and used the shorter legs thus decreasing the space between the shelves. (The move from the bottom shelf is because I rearranged the room and there is a heat/AC vent right behind it and I didn’t want it blowing directly onto the amps) This rack has legs that are all the same length, except for one set which are a few inches longer.
I figure the buzzing was reflecting off of the shelves in such a way that it amplified it to where it became noticeable - just barely. When I slide the amps back a few inches the noise almost disappeared from hearing. I slide them back forward to where they were before and I could hear it again.
What I did to remedy it was to place a couple of acoustic panels beneath the amps, reconfigure the rack putting the longer legs on the shelf they reside on, thus increasing the ceiling height above them and reducing the reflection of the buzzing sound, and sliding them back an inch or two from the front. Now, I have to strain in a very quiet setting (i.e. the refrigerator in the other room isn’t running, and the road noise outside is low) and then I can just barely make it out.
So I probably didn’t need the the power conditioner to fix this problem after all. Though it is a nice piece of equipment and I’ll keep in place because who doesn’t want clean power?
The red lines I added are the longer shelf legs.
