Marshall 1974x Transformer Hum (60 cycle hum)

[photomat]

I just got my Marshall 1974x back from warranty service on the OT transformer that went bad. I don't want to make this a thread about that issue (there are already a few), but I did notice that the transformer hums quite a bit. With the volume off, you can really hear it with your ear anywhere near the amp. When I turn the volume on the non vibrato channel between 2 and 9 you can really hear the harsh 60 cycle hum. It goes away at 10 and is not so pronounced on the vibrato channel.

I know that it was not noisy at all before, but now it is just annoying. I was wondering if anyone else had had hum issues on their 1974x transformer replacements?

In one sense, I am glad I heard it, as I noticed when I was looking around that the amp tech had turned the speaker impedance to 8 ohms and had not reset it to 16.

Any one else experience this issue?

[rockinlespaul]

No hum here. Take it back, its not right imho.

[sdgvintage]

Sounds like a grounding issue. You should definately get it back to service.