Hum on Tube Amp - Can't find source


I have a hum (60hz) I can hear on my speakers and it happens with my tube monoblocks (either of them).  With or without interconnects, it even happens on either amp (have tried one at a time) with every circuit on the house tripped/disconnected, every other component disconnected from the wall (including the Internet/CaTV line) and no interconnects.  

One amp has it as soon as it warms up whereas the other one is intermittent.

Hum X doesn't solve it, iFi Ground defender either, AVA HumDinger on powerline  doesn't solve it either.

I have replaced the tubes and both amps were just tested at the factory.  Replaced the circuit breaker, tightened every wire on the breaker box, checked and cleaned all connections to ground rod.  Added a hum eliminator to the internet line.

Hum cycles a bit with the tube glow matching the cycles.

I'm waiting on the power company to come check the power coming to the house.

Thoughts?

ervikingo

Showing 3 responses by dweller

Had this problem with a Primaluna Prologue Premium and Klipsch LaScallas.

Sent amp to Upscale Audio (Indianapolis to L.A.) who checked out the amp and said it was working normally.

Never fixed the problem so I sold the amp.

I believe the problem is/was in my main panel but didn't want to hire an electrician.

Doesn't affect my current equipment. Good luck.

"I have replaced the tubes and both amps were just tested at the factory."

You're telling us the factory didn't notice you were using the wrong tubes?

Sheesh.

Do the P.S. Audio Power Plants eliminate hum from tube amps? Know first-hand the heartbreak of Tube hum (Prima Luna Prologue Premium w/Klipsch LaScalla II).

This would be a godsend.