Help with amp problem please

[PurityS.L.G]

Was jamming on my triple recto and decided to switch to vintage mode on the red channel and I get a low rumbling/sputtering noise. After messing with settings and stuff to figure out where it was coming from, the amp rumbles only in raw and vintage modes on the red and orange channels as well as both modes on green channel. This happens no matter what if I switch to bold/spongy mode and tube/diode mode. Is this a bad V1 and or V2 preamp tube?

Of course I have no fkn spare preamp tubes at the moment to test out this theory so wanted to see if this sounded like a familiar problem with anybody and they can help me.

 

[napalmdeath]

Deoxit.. Pull it out, and clean things up. Switches, pots, jacks, tube sockets, etc.. It's a start before tubes. Hell, even if its a preamp tube, it's likely one. I'd shoot for finding just a couple 12AX7's.

 

[glpg80]

Vintage mode adds NFB into the amp, modern mode is with no NFB.

Sounds like a tube problem. Pull all of the preamp tubes out of the amp except for the phase inverter and see if it still does it. If it still does it put them back in and Then pull the inner two power tubes and half the impedance, then put those back in and then pull the outer two tubes and test again.

This will let you see what follows what or whether it’s in the preamp. If after all of that, deoxit time in the preamp out and effects loop

 

[PurityS.L.G]

Vintage mode adds NFB into the amp, modern mode is with no NFB.

Sounds like a tube problem. Pull all of the preamp tubes out of the amp except for the phase inverter and see if it still does it. If it still does it put them back in and Then pull the inner two power tubes and half the impedance, then put those back in and then pull the outer two tubes and test again.

This will let you see what follows what or whether it’s in the preamp. If after all of that, deoxit time in the preamp out and effects loop

Excellent. Thank you!