hybrid amp volume fades in and out

Welcome to the forum.

Danielle, your presumption about the preamp tube is one possibility or likelihood.

I think it is particularly valid, because you describe a 'soft' or gradual failure, and not complete 'power out'.

It is also the type of intermittency that applies to glass & cathode tubes, and not to other fuses or circuitry, IMO. :idea:

Thank you very much. I will try another preamp tube.

I tried putting in a new preamp tube but the same in/out fading keeps happening. does anyone know what else may be causing this?

I tried putting in a new preamp tube but the same in/out fading keeps happening. does anyone know what else may be causing this?

That is a shame, I'm sorry, and a bit surprised. Fading is a very odd occurrence, without a crackle or pop?

The next thing could be the volume control or pot itself. All suggestions welcome - I'll research the specific amp.

Sometimes this can be resolved with a contact cleaner spray, but as you know, not the first thing I'd have considered.

There is a rarity too that I've found in tube amps, when a biasing resistor fades or fails, but it has been a long shot usually.

This is all I could find on a T30R, and somebody on an amp forum complained about a Power Supply failure or complete meltdown. No need for that particular link. So, this is minimal. http://www.buzzillions.com/reviews/guitar-research-t30r-combo-amp-reviews

But if that was the case with yours, your power-on light would fade or fail too, giving a clear sign of no power getting by.

I'm back to edit - I know you're not simple, but try a different guitar cord. Patronize us, please, just trying to help. 8)

Good luck!

I heard it should crackle when a tube goes