Does you power amp have a two prong plug? If so try adding a wire from the
chassis to a real Earth ground. If your power amp has a three prong plug,
try it with one of those two prog adapters with no ground at all.

James. )


"johnelstad" wrote in message
oups.com...
Well, I'm at my wit's end, but I'm hoping this will be obvious to
someone with more experience. Please help if you can.

I recently noticed a mild-moderate hum coming from my speakers that is
constant regardless of volume or input. Here are the results of my
attempts to isolate it.

Turn off and unplug pre-amp = hum (no change)
Disconnect pre-amp output cable = no hum
Replace cable connecting pre-amp to amp = hum

Not sure if this is helpful, but my pre-amp has a headphone amp that
produces no hum.

Equipment:
Sonic Frontiers Line 1 Tube Preamp w/ 5-year-old tubes
McCormack DNA-1 Solid State Amplifier
NHT 1.5 speakers.

Thanks a bunch!

John