Help me solve another speaker hum thread :)

Are you sure the small tubes are in the correct positions in both amps? What about swapping them to see if the noise follows them? You could try one at a time. Do you have any WiFi routers or APs nearby?

Ya I’m sure the tubes are correct. I tried swapping all the tubes out with the other amp but that did not effect anything. No wifi or AP’s. I do live about 0.2 miles from 3 AM radio towers and 1 FM radio tower... could that be causing issues? I wouldn’t think so?

I spoke to my dealer today, they are gonna come take a look. I'll update the thread when they do. In the meantime if anyone has any great ideas, feel free to share :)

if its not DC or other power issues coming from your line, dimmers are bad for adding noise on the line, than its probably a tube. Try tapping the tubes when on see if your getting any microphonics out of any of them. Try taping them quite hard to see if there may be some particles trapped in a tubes grid etc.. if you have a second set of tubes try them. 

You seem to have done all the normal things we do to find hum, other than internal issues ie bad component, its most likely tubes or power delivery from your wall. maybe try an different outlet other than your dedicated lines, extension cord may be useful. 

I was getting a hum from my McIntosh MC302 amp and C2500 tube preamp.  It took a lot of snooping but it turned out to be the Apple iPad charger I had temporarily plugged into the Furutech power distribution block.  Once I removed it, hum was totally gone.