VOX AC 30 VR squiling tone

[Stewen]

Hallo ! As a tubeamp -tech I am not so fond of solid state and specially not this AC30 VR which has nothing internal in common with the old AC30īs. This is a hybridamp with just one 12AX7 and this tube is working with just 30 VDC on
the anodes. The amp is just three years old and not used much. It just sends out a high note also with the volumes at zero ! I have the schematic . Would be very happy for some advice what to do - look for . Regards Stewen

[J M Fahey]

Ok, start by posting the schematic.
If possible, also a couple gut pictures, so we have an idea of what are we dealing with

[Mick Bailey]

Maybe you have a microphonic tube. From what I've seen of the VR amps they run the tube in push-pull as a power amp stage.