Intermittent low hum/buzz


I know this has been covered here on these forums before but I gotta throw it out there one more time . So heres the set up , a dedicated 20 amp circuit on a full space breaker (not a split) so no shared neutral ,number 12 romex into a plastic box which I never use but I figured it would be best for what Im doing here  then finally a hospital grade Isolated ground receptacle.All the cables both AC and signal are all either AQ, Kimber or Acustic Zen ,power conditioner is Torus model 15, power amp Prima Luna evo 400 ,pre amp Prima Luna evo 200 ,sources Aurender A100 ,anolog is Gold note phono pre and Planar 6 turntable with a moving coil cart.So that all seems pretty legit to me so why in the hell do I have this intermittent low level hum or really maybe more of a buzz In the mid range driver? ,oh speakers are Focal Kanta 2,s You have to put your ear right up to the speakers to here it but it’s driving me crazy ,Thanks in advance.

bikeboy52

Showing 1 response by jea48

@bikeboy52 ,

It could be a signal tube with dirty and or corroded tube pin(s) to tube socket contact(s) connection(s). Pull each signal tube then plug it back in repeating the process a few times. This will clean the tube pins to tube socket contact connection.

You could try just the preamp first and see if that solves the problem. If not do the signal tubes on the power amp.

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