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Hum
Apr 13, 2022 12:37:54 GMT
Post by brettj on Apr 13, 2022 12:37:54 GMT
My amp has a persistent and loud hum.
How the heck do I get rid of it (but keep the amp).
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Hum
Apr 13, 2022 13:07:00 GMT
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Post by John on Apr 13, 2022 13:07:00 GMT
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Hum
Apr 13, 2022 14:28:44 GMT
Post by MartinT on Apr 13, 2022 14:28:44 GMT
My amp has a persistent and loud hum. From any input? Disconnect everything from it except power and start from there. If it hums on its own listen to it closely for transformer (mechanical) hum. Then add the speaker cables. Then add one set of inputs at a time. At what point does it hum? Check that it is earthed at the power plug. The most usual cause of hum is one of the inputs having bad earth or an earth loop. |
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Hum
Apr 13, 2022 16:55:17 GMT
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Post by jandl100 on Apr 13, 2022 16:55:17 GMT
Has it always hummed?
If it's just started, then did you do something to the system?
If it's just started with no apparent cause, then check that all cable connections are secure.
Then follow Martin's systematic check routine.
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Hum
Apr 13, 2022 21:24:18 GMT
Post by brettj on Apr 13, 2022 21:24:18 GMT
It's always had the hum.
I asked the guy when he recapped it last year about the hum.
He said, "What hum?"
Even with nothing plugged in (other than the power cord), it still hums...
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Hum
Apr 14, 2022 3:52:52 GMT
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MartinT likes this
Post by jandl100 on Apr 14, 2022 3:52:52 GMT
What hum?
Hah, yes, I've been there.
We are sensitive creatures.
So. It's coming from the amp itself, not through the speaker?
My guess is that it's transformer hum.
Try a DC blocker.
Try really tightening the screws that hold the transformer to the chassis. Do that in stages to find optimum tightness.
Try mounting the transformer on rubber grommets or similar.
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Hum
Apr 14, 2022 5:13:02 GMT
Post by MartinT on Apr 14, 2022 5:13:02 GMT
Sounds like mechanical transformer hum, where the windings vibrate with the mains waveform, worse if it's distorted or has DC on it. A DC blocker or regenerator will help.
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Hum
Apr 14, 2022 10:12:28 GMT
Post by MikeMusic on Apr 14, 2022 10:12:28 GMT
When my room is quiet I can hear the Tivo
When the toothbrush charger is plugged in I can hear that
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Hum
Apr 14, 2022 11:35:29 GMT
Post by brettj on Apr 14, 2022 11:35:29 GMT
Thanks Jerry John Martin Mike and Ringo
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Hum
Apr 14, 2022 12:00:32 GMT
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Post by jandl100 on Apr 14, 2022 12:00:32 GMT
Or can you put the amp in a cupboard/sideboard etc?
This might reduce the sound.
Or it might reverberate and make it worse!
I've had both happen.
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Post by brettj on Apr 14, 2022 21:52:20 GMT
I already use the cupboard technique Jerry.
The only way I've been allowed to have such an 'ugly' system.
Have the amp on BR Big Pads, on a shelf with Sorbothane pads underneath.
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Hum
Apr 15, 2022 1:23:10 GMT
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Post by julesd68 on Apr 15, 2022 1:23:10 GMT
I remember tightening the screws on a slightly noisy transformer as Jerry suggested made a useful improvement for me some years ago.
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Hum
Apr 17, 2022 22:35:01 GMT
Post by brettj on Apr 17, 2022 22:35:01 GMT
Have gone ahead and bought an Audiolab DC Block from Analogueseduction.
Have to sell something to pay for it though.
Not sure what to do power cable wise.
My amp has a Mad Scientist Nitro Nano.
The Audiolab has an IEC male and female plug.
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Hum
Apr 18, 2022 7:27:56 GMT
Post by MartinT on Apr 18, 2022 7:27:56 GMT
The first thing to do is try it with any old cable and see if the hum reduces.
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