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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
bikeboy52 OP
190 posts
 

Thx spatialking,Im inclined to think thats right, the last thing I did was change out the only remaining stock AC cable this week (no joy) but over the years component’s have have been changed out and moved with no real overall plan for cable runs and placement. My thinking is to tear down the entire system down after building a longer and deeper shelf,the whole system sits on a free floating shelf.A good portion of the original cabling was run thru chases inside the walls for a clean look and that also helped with keeping the AC from running to close to interconnects. If nothing else it’ll at least make me feel like Im working on it.

geof3
1,129 posts
 

I don’t think the Planar 6’s tonearm is grounded. Give that a shot. Ground from your stage to the tonearm and/or drive motor.

jea48
4,489 posts
 

@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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bikeboy52 OP
190 posts
 

Thx ,Jea48 I found it today (again) I swapped out the rca interconnects between the pre amp and the power amp. They’re was a pair of Kimbers in there before and I switched them out for an old budget pair of Adioquests. So possibly its a shielding thing the Kimbers have none or its caused by the cables being run through the wall or both.The home run circuit that powers the system is not running anywhere near this space but there is one or more existing circuits in that wall between the family room and the master bedroom.I just ran those Adioquests outside the wall as a quick test so I don’t really know for sure yet or I could be completely out to lunch on the whole theory because it’s intermittent, It’s frustrating, thats why I say “ I found it again “ I’ve been into Hi Fi since I was a teen but only vacum tubes for three years or so I’ve got a complete solid state system as well so I could also change out the pre and power amps to rule those out per your suggestion also ,thx again Jea48.

 

 

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