Thank you. I have thought of doing just that. I was hoping someone might have had a similar experience. The amps are very heavy and a bit difficult to work on. But I'll probably do that.
Noise problem as tube amp warms up
I recently installed some NOS Russian 6922 tubes in my Sonic Frontiers Power 3 monoblocks. One amp makes a siren sound ascending in pitch from low to high as it warms up. After that it seems to be fine. It sounds a lot like an analog synthesizer from back in the day. Can anyone help me diagnose the problem please? Some preliminary research suggests a bad input tube tube or possibly a filter cap. The old tubes made a similar sound, but softer and descending pitch when powering down.Thanks.