Preamp issue?

Every issue I have had with tube preamps has been the result of faulty tubes.  Noisey, popping sound like pop corn, microphonic howl.  But never what you describe.  But I suppose it is possible.  Defintely swap the tubes - that is the first step in the process of elimination.

Are you sure it is your preamp?  Hate to state the obvious but you always need a spare set for this reason and for when they eventually crap out.

Good luck!

I'm voting for tube issues too. I've had power tubes go bad very quickly, leading to popping, crackling and the like.

The good thing about my pre coming with crappy Chinese tubes was that I replaced them immediately, leaving me a spare set (of inferior quality..) to diagnose problems with as to use while I wait for good replacements.

The first troubleshooting step should be to swap the interconnect cables at the amplifier input end and see if the issue moves to the other side. This will show that the issue is in the pre-amp (or possibly source) and not in the amplifier. If you determine that the issue is in the pre-amp or source, you can forget about troubleshooting the amp and speakers. You can swap other cables to isolate the pre-amp or source as the cause of the issue. Once you know the problem is in a certain component, then troubleshoot that component. If it's the pre-amp, swap the tubes side to side to see if the problem moves.

Of course, turn off the power to everything when you're swapping cables and especially tubes......

^^ What reubent said. Swapping the interconnect cables left for right is your first step, otherwise you don't know if its the preamp or the amps.

tubes dont last forever......it might be time for a new ones.