2. amps-preamps
  3. 163233-36966

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

Showing 1 response by mlsstl

mlsstl
1,457 posts
 
Have you checked your outlets with a receptacle tester? It is possible that circuit in your house is wired backwards or has a missing ground. Or, that one of the power cords you are using is bad.  

And don't leave the CDP out of the picture. It could be the problem and your current integrated isn't sensitive to that problem. Try a different music source with the Pass gear just to eliminate that possibility. 
More to discover