Why my PA-10 bias voltage always shift to 24V every time I switch on, even after I adjusted it to 16.5V as recommended in the manual? Is there anyting wrong with my unit?

Please take 15 ? 25 min to warm up the tube. It will be more stable when you adjust the tube to 16.5V.

I did adjust the PA-10 Bias after I turn it on for many hours. The Bias voltage is still fluctuating and then shifted after I used it for a few hour. Please help!

Do you have another Tube ? If yes, please try it. Take note that some tube will be more stable. Send your comments or report to [email protected]