Hum or buzzing issues with high gain?

[CoteRotie]

I was getting some intermittent hum or buzzing at high gain (SM7 mic) with my newly built N72. I took it in to work, ran a frequency sweep, spectrum analysis, looked at the supplies, output signal, etc, all was good. Now I know enough to keep fluorescent lights out of my studio, but all the lights in the rest of the building were recently replaced with those compact fluorescent bulbs. Some of the cheap ones are such efficient noise generators that they can cause problems from different floors or different rooms in the same building, and that's what was getting in to my pres. So it's worth checking if you have a problem. Also beware that several states are introducing legislation to outlaw the old fashioned incandescent bulb and we may get stuck with these trash emitters.

Regards,

John

[sardonic_z]

I had a similar noise issue running my FW hub too close to my preamp rack.