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Hum or buzz through speakers

I just turned over my system from all B&K to Audio research and McCormack. I was running the Audio Research through the B&K until Monday when I put the McCormack DNA-1 in place. I am hearing a hum or buzz through my Vandersteen's audible from three feet away. Preamp is ARC SP9MK2. Tubes are 6922 Golden Dragons which I am going to change over to some Amperex 7308 USN-CEP. Would this be tube noise that perhaps the McCormack is picking up where the B&K did not or is there something in the McCormack amp that would cause this.

Eagleman
eagleman6722
newbee
4,767 posts
 
Sounds like a 60 cycle hum - a grounding problem most likely. Try floating the ground at your amp and see what happens. Usually it will go away. This is usually not tube noise but tubes do have a residual noise typically heard as a hiss sound. If your amp has a high input sensitivity and your speakers are very effieient you could well be hearing tube noise. If so, be careful buying NOS tubes, many are not all that quiet.
swampwalker's avatar
swampwalker
5,138 posts
 
Newbee (time to change your name, dude) is most likely right. In addition to poor ground at outlet, could also be a bad IC ground, or induced hum from an IC or speaker cable near the power cord.
restock
831 posts
 
I had a 60Hz hum in my system due to an antenna/cable connection, when the TV was connected to my Jolida amp. The TV cable had a ground that is different from the electrical ground thus resulting in a ground loop.

Best way to find out is to disconnect all ICs from your amp but leave the speakers connected. If you still hear hum then it might be a problem with the amp. Then slowly start connecting one piece at a time, so that you find the faulty piece.

Good luck.
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