Ground hum?

Posted by mbrierley (A) on January 20, 2024 at 10:13:05

Hey all- new to this asylum. I added a new pre amp to my chain a few months back. I was previously using the built in pre amp. I never had any hum with the built in pre amp and I do now. I make my own cables, so tonight I went straight from built in preamp, direct to the amp and bang, no hum.

My initial thought is that I had connected the cable shield to the wrong end but cables are as they should be. Both external pre and deck are earthed. I removed the earth from the external pre and the hum got worse.

Any ideas? Typically only hums above 80db.

I'm loathe to buy a new preamp if this happens again.

For reference, the pre is a musical fidelity V90 LPS that get great reviews. I upgraded the power supply to a linear power supply unit as well.

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Topic - Ground hum? - mbrierley 10:13:05 01/20/24 (12)

First... - Cougar 09:19:41 01/21/24 (0)

RE: Ground hum? - Rod M 12:55:35 01/20/24 (9)

Not MM/MC - mbrierley 00:23:52 01/22/24 (2)

Not even pre-amp - mbrierley 08:15:35 02/19/24 (1)

RE: Not even pre-amp - mbrierley 05:56:40 02/20/24 (0)

Not MM/MC - mbrierley 06:09:54 01/21/24 (0)

RE: Ground hum? - mbrierley 15:19:41 01/20/24 (4)

When I had a ground loop issue, the phono pre was the cause. - ghost of olddude55 05:15:14 01/21/24 (3)

Mixed Grounds - Triode_Kingdom 07:19:29 01/21/24 (2)

So I've read. - ghost of olddude55 07:28:51 01/21/24 (1)

RE: So I've read. - Triode_Kingdom 08:23:56 01/21/24 (0)

Might be a ground loop. - ghost of olddude55 11:43:25 01/20/24 (0)

Ground hum?

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