Amplifier Noise - My Mystery

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Gohde

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Hi all,

Looking for some advice.

I?m using an Aura VA100 ii (a MOSFET amp from mid-90s). Overall, enjoying the sound.

But there is a faint noise that:
- is about 5khz with a hint of static, both channels
- same regardless of gain (at volume down it?s there)
- same regardless of inputs or connections
- same if I plug it in unearthed
- same if I unplug all other components close by

When I listen to music, I cannot hear it. But I listen quite closely and it is just (barely) audible from about 1-2m away (if it?s very quiet). But because of the high pitch it is messing with me too - yesterday I was irritated at it from a distance only to realize the am was off.  :fuse:

I had the amp serviced (a resistor had burnt out) and the service replaced (resistor, two caps, and a small transistor).

Any pointers/explanations of this type of noise is an obvious diagnosis and a common problem. I have tried to research, but came up short. Most noises are all about ground loops or cable noise or toroidal mechanical noise. Since it is there irrespective of volume and input, I?m not sure if that rules out the amplifier section and might be the power supply?
 

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