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Hum on Tube Amp - Can't find source

I have a hum (60hz) I can hear on my speakers and it happens with my tube monoblocks (either of them).  With or without interconnects, it even happens on either amp (have tried one at a time) with every circuit on the house tripped/disconnected, every other component disconnected from the wall (including the Internet/CaTV line) and no interconnects.  

One amp has it as soon as it warms up whereas the other one is intermittent.

Hum X doesn't solve it, iFi Ground defender either, AVA HumDinger on powerline  doesn't solve it either.

I have replaced the tubes and both amps were just tested at the factory.  Replaced the circuit breaker, tightened every wire on the breaker box, checked and cleaned all connections to ground rod.  Added a hum eliminator to the internet line.

Hum cycles a bit with the tube glow matching the cycles.

I'm waiting on the power company to come check the power coming to the house.

Thoughts?

ervikingo
ervikingo OP
152 posts
 

@jea48 mine is different.  Please click on the audio and video I just posted.

@atmasphere thanks!

dpop
293 posts
 

I’ve had a number of tube amps over the years, both integrated and headphone. By design, they all produced some amount of hum. Even though I love the sound tubes produce (which in stereo mode, rarely ever 100% correctly sum to mono in headphones), I couldn’t tolerate the hum (and I’m not referring to the physical or mechanical transformer hum) the amps produced. I no longer have the patience for tubes. I personally now prefer the low distortion and low noise floors solid state provides. I believe what you’re hearing @ervikingo is hum produced by the amps, and it has no relation to the quality of AC power you’re supplying it.

jaytor's avatar
jaytor
765 posts
 

@dpop - My amps have no audible hum with my ear up against the speakers. My speakers are 98db/w efficient. All tube amps don't have hum problems, and all solid state amps are not hum free.

rocray's avatar
rocray
1,448 posts
 

Have you reached out to Manley? 

ervikingo OP
152 posts
 

@rocray Yes I have.  They have been great!  The amps went to them for an unrelated check up as I was resetting up my big system.  They found no issues with the amps other than a non-oem fuse holder (by a prior owner) which was removed and brought back to spec.

I have followed their instructions and it makes sense to me that it ain't the amps.

If it were, I could see one of them exhibiting the behavior but not both.

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