Intermittent low hum/buzz

Tube noise? Tubes are noisy. They just are. I’ve tried multiple setups, but the low level noise of tube gear just drove me crazy. YMMV…

Thx Geof3 ,I thought about that but the thing is when that buzz is absent probably 75% of the time the system is dead quiet with a digital source and with the analog source just the typical phono stage swoosh you’d expect.I don’t have enough experience to know this for certain but this seems AC related to me .

Tinnitus is caused internally by the auditory and nervous systems, without any external stimuli. While some people perceive us as a form of low-frequency tenets, such as Venus We, some report that it is not internal, worse from the outside inside their homes.

Regards: Printers Insider

I spent several days digging out the last bit of hum from my system.   Believe me, any hum at all will degrade the sound at some level.  I found I had to not only tie all my electrical cords to the same Earth point but I also had to put ferrite beads on some power cables since that hf hash came through as a low level hum.  Shielded power cables are a must but frankly, distance is your best friend.   Separate the analog power and digital power cables, and keep both well separated from any interconnects.    Pay attention to what is in your rack, some of the hum coupled through the space between shelves from noisy amplifiers and injected it into susceptible components above and below the noise source.

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.

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.

@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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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.

I had a hum for over a year and tried everything.  Spent $750 for a guy to come to my house to check everything and he could not figure it out.  Then I tried a $80 dollar Hum X and the problem is gone.

HUM X does help but for my system it was renamed HUM-(minus) because while there was a perceptible diminishing of hum it wasn't gone, The improvement was well worth the $50 bucks I paid. For what its worth a solid clay brick on top of the transformer cage cooled the hum too but since hum is vibration I noticed additional clarity in playback overall. The Mad Scientists Tube toppers helped also. 3 pair on top of the three sets of preamp tubes. More resolution as well. By passed the Furman power stripe which cleared the tunes a little and also took out a trance amount of hum. Hum is a remarkably resilient little demon. Plus, my room is so quiet that an ant walking behind my sub causes a quavering in the treble.  

>>>You have to put your ear right up to the speakers to here it<<<

@bikeboy52 Just wondering if the noise is present, *equally*, in both the L & R channels?

>>>Tubes are noisy. They just are. I’ve tried multiple setups, but the low level noise of tube gear just drove me crazy.<<<

@geof3 Totally with you there. I couldn't take it anymore, and gave up on them years ago.

>>>Pay attention to what is in your rack, some of the hum coupled through the space between shelves from noisy amplifiers and injected it into susceptible components above and below the noise source.<<<

@spatialking I couldn't agree more. Many don't realize this until all equipment is physically placed, and *then* powered up and listened to. When setting up an audio system, I recommend starting with speakers and amplifier hooked up first (with amplifier inputs shorted), then listen for noise. After removing shorting plugs on power amp inputs, connect your pre-amp to your power amp (with one source input shorted). Listening to the shorted input, if there's no noise, continue on with the next component, and listen for noise...and so on. This many times will allow you to quickly identify and isolate which pieces of equipment are not playing nicely together. You may then have to physically move pieces of equipment and cabling to eliminate noise. While performing this staged setup, keep only equipment that has been connected, powered up. 

>>>So possibly its a shielding thing the Kimbers have none<<<

@bikeboy52 Give me a heavy braided shield (for example Belden 1505F or Blue Jeans LC-1) any day over non-shielded Kimbers. I understand Kimber's theory, but in many electrically noisy environments, Kimber RCA interconnects *just can't* reject the noise. 

@dpop Yes my noise was the same in both channels. Annoying as all get out to be in for close to 30k in equipment and have a problem like that and quite a relief to solve it. My next move probably this winter is a move much like geof3 suggested which will be to build a appropriately sized shelf with a actual equipment placement plan before hand. I was never able to do that before but I think Im done buying new gear at this point I think anyway, Best !

@bikeboy52 That "buzz" in the midrange is most likely AC line harmonics seeping in through parasitic capacitances and parasitic inductive coupling in the chassis, line cords, and developing a voltage on your shields.   You do need to get rid of it, because it is affecting your clarity and definition of the sound, even though it is at a low level.   You have your work cut out for you, it took me a long time to get rid of it in my system.