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?
That happened to me a month ago, I heard the hum through both of my speakers, very annoying. That hum noise was from my KT88. Later I swapped my tubes to another KT120. Noise is gone, so quiet. That was my fixed. Nothing related to any ground, power conditioner. If you have extra set of tubes, try swap it and see if that helps.
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Wow, these tube amps are more sensitive then I thought. Come to think of it, I was really into tube headphone amps for a while. I discovered that they too were very sensitive to headphone impedance, when it came to low level hum produced by the amp. I weighted the issue, and concluded that the headache just wasn't worth it. I was also many times hearing sporadic plinks, plunks, and noise bursts with tubes, and that drove me a little crazy too. |
It looks like the one I posted. Mine is a TPS3A111000 (no superseded by TPS3A111002) https://mall.industry.siemens.com/mall/en/us/Catalog/Product/?mlfb=US2%3ATPS3A111002 Thus: voltage code: 120/240V, 10,3W 100kA per phase EMI/RFI filtering (sine wave tracking), Ground integrated monitoring, Protection modes L-N, L-G, N-G, L-l (whatever all of that means!)
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@zombiedad swapped the KT77 also swapped the 7044 and 12ax7 from one unit to the other. I suspect that 12ax7 is the problem. Speaker wires are AQ Rocket directional 18" long |
