XTC: Whoosing white noise on Red Channel

[Skeeter]

Hi all, I recently bought a used XTC - and everything is great, I've opened it up and looked at the tubes, etc...

The only issue is there is a lot of white noise, like a whoosing sound on the Red Channel only. This is always present, even with my guitar volume turned off, not playing.

The Blue channel is almost dead quite, even boosted with a pedal in front. So, while I know there is always some noise on a high gain amps, it doesn't seem like it makes sense that it would be some much more present on the Red Channel. And if it was the wall socket, or other electronic devices, it seems like it would happen on th blue channel as well?

So, I'm wondering if it's one of the pre-amp tubes? Looks like V3 is the one that has is half-dedicated to the Red Channel only.

Any other ideas? Is this just how the red channel is?

Thanks!

 

[Setneck]

Well, it might be the tube, but note that Red channel is hissing quite much itself. Is Your amp Pre or Post2004? If Post, additional R12 mod make the Red hissing more too.

The dedicated triode for a Red is V2B so You might try the other tube in V2 if You want to check it.

Regards, Andy

 

[Ventura]

Likely preamp tube(s).