getting a high-pitch whine, droning noise from my amp...

[elkym]

the noise seems to come and go at a regular slow sweep, sort of like a phaser...

It's a peavey valveking (3 12ax7s and two 6L6s stock)

I switched out the V1 preamp for a 12at7 (was a stock 12ax7).

I also switched out the phase inverter for a 12at7, but that seems not to make the noise...

Help me sort this out, will ya?

I kinda like the 12at7 in the preamp too, but I'm not sure I like this noise...

[elkym]

morning bump

[Spudman]

I just had something similar to that. I replaced all the preamp tubes and the problem went away.

[elkym]

so you're saying that I can't use this tube?

sad...

[TweeDLX]

so you're saying that I can't use this tube?

sad...
Have you tried replacing the tube in question with a known good tube? It might just be this particular tube has an issue. You can always try a similar 12AT7 and see if that performs better. If you replace the questionable one with one you know is "good", and the problem persists, then maybe it's the circuit that doesn't like that tube. http://www.thegearpage.net/board/images/icons/icon7.gif

Mike