Tube preamp ground loop issue?

[AndrewCAudiophile]

Any chance you have a TV or a computer wired in with this? I actually ran into a hum problem last night using not my equipment. As soon as I connected the computer source it hummed. Unhooked the cable line and about half of it went away. I moved the computer to share a power outlet with the rest of the gear and it shut up. The preamp has a ground. The amp does not, but the computer does and the cable line is grounded as well.

I am using my laptop to play music through the DAC into the preamp. However I've had the laptop in a totally different room not plugged in and the issue persists. Something else strange is going on. Was thinking of purchasing a ground loop eliminator box.

 

[gadget73]

does it stop if you unplug the laptop? If its on battery and not connected to anything else plugged in to the wall, it can't be a ground loop.

 

[AndrewCAudiophile]

does it stop if you unplug the laptop? If its on battery and not connected to anything else plugged in to the wall, it can't be a ground loop.

Doesn't stop..laptop plugged in or unplugged makes no difference unfortunately.

 

[gadget73]

ok, well its not a computer-related ground loop then. Does it hum with no sources at all connected? Also I notice in your original post you said "amplifiers", are you running a pair of mono amps by chance?

I'll admit at this point I'm sort of fishing for ideas but trying to get an exact picture of what you have hooked up and how just to see if anything pops out. Very well may be something going on with the wiring. If absolutely nothing else makes sense, try a good heavy cord from your power strip to an outlet on a different circuit. If that shuts it up, either you have something making noise on that branch or something goofy with the outlet(s).