Is it normal for my Arcam receiver and Adcom amplifier to have a hum coming out of the power supplies? For the Arcam 300 receiver you have to get real close in order to hear it, but the Adcom 7807 I can always slightly hear from my seating position. I have a dedicated room, so it's pretty quiet. I am running a dedicated 20 amps electrical outlet for the Adcom. When the Adcom amp is running and I turn on the Arcam receiver, the hum increases on the Adcom amplifier as the Arcam clicks to turn on, but then after two seconds or so the hum on the Adcom comes down to its usual level.
One more detail, everytime the microwave is used, the hum shows its ugly head even more, it doubles, only on the Adcom amplifier. The microwave being in the kitchen, get its power from a different line.
Is this normal, or do I have an electrical problem? The house is 17 years old.
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