2. amps-preamps
  3. 1098390944

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
eagleman6722 OP
217 posts
 
Well,
I changed preamps from the ARC to the TAD-150. The hum or buzz was fairly low and not audible unless I got right near the speakers. When I hooked up the TAD-150 I could hear the hum and buzz from across the room. I unhooked the IC's and it seems to appear when the preamp IC is connected. Sounds like the 60HZ that newbee was talking about. Any other Ideas. This pre sounds fabulous but, I can't block out the noise.....

Eagleman
newbee
4,778 posts
 
Did you try putting a cheater plug on the amp PC. Only costs a couple of bucks at the local hardware store and is usually quite effective. That is what I meant by "floating the ground" as the cheater plug removes the ground from the circuit. This is not really a major safety issue if the pre amp has its ground intact, and even then...... Try it.
eagleman6722 OP
217 posts
 
Thanks Newbee, i will give that a shot....
eagleman6722 OP
217 posts
 
Well newbee, that didn't work. ny other ideas are welcome.
newbee
4,778 posts
 
If the input sensitivity of the McCormack is higher than the B&K it is quite possible that, as Steve Mc said, you are now hearing the noise floor of your pre-amp a bit more than before, although usually this is more hiss than buzz. See what happens when you change tubes, I suspect you will like the tone of the Amperex's much more (assuming that they are low noise tubes.) At least you can't hear it from more than 3ft away...........:-)
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