How to Eliminate Hum? CDP + Pass Preamp + Amp Setup.


HELP! How do I eliminate Hum? I just bought a demo, Pass XP-22 and X250.8. 60Hz hum is audible across the room at no volume. It’s only a 60Hz hum, not 120Hz/buzz. Here’s the setup into same AC wall plug.

Amp only (no Preamp): Very slight hum audible inches from speaker
Amp + Preamp: 0 Volume: Slight hum audible 6 ft away
Amp + Preamp: 01 Volume: Slight hum audible across room.
Amp + Preamp: 99 Volume: Moderate hum audible across room

I tried the following without any success:
- Connecting CDP
- Used different interconnects
- No cables touch nor cross.
- Separated the preamp from the power supply module.
- Used different AC outlets
- Used different AC Power strips for testing
- Each unit on different rack.

My integrated amp doesn’t have this problem.  The sonics are great, except for the annoying hum. I have 9 more days of trial period... How do I solve the hum issue without killing the sonics?


88man

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