Hi, everyone. I know very little about electric guitars and amps, but I bought a Peavey Heritage VTX Amp a few years ago cheap on Craigslist before I knew I'd have to spend $300 for tubes and repair shortly after.

Anyway it works most of the time, but there are times when it goes really quiet but if I continue to play, suddenly it'll make a deafeningly loud pop after which it sounds great for a while until the same thing happens. I've probably already spent too much on this thing, and I don't know if it's worth shelling out more money or just getting another amp to suit my purposes which is strictly for recording. I have a set of 4 matched Tesla tubes in the power amp stage with only a few hours on them. The preamp stage I assume is solid state.

So 2 questions:

Do you have any guesses as to why it goes quiet and clears up after the pop?

Also, if I do decide to continue using the amp is it possible to use only the tube output stage and cabinet and connect different amp heads to it? The manual says that the power amp input has a sensitivity of 1 Volt RMS and an input impedance of 20K Ohms. I don't know what that means.

Here's a link to the manual if necessary:

Thank you!