Dmitriy
New member
Hello all! Recently bought this amp, it has yellow led inside I suspect it's old model. However, when trying to check and adjust bias according to manual (2 bias adjustment knobs) something looks really strange.
Right knob not responding at all, doesn't matter which tube is being checked. Left knob (fine adjustment) works, but really strange, for ex: Indicator for V4 tube was showing that tube is under biased, then I turned fine adjustment clockwise - nothing. Turned counterclockwise a little and indicator told tube is ok biased (it should be opposite direction I guess? or It's inverted?)
Other tubes have exactly same behavior. But surprisingly amp works good I didn't find anything related to sound/biasing problem in it...
My question is - does bias adjustment system supposed to work like this? Or how it works in your amp? Please describe steps how you do it in your amp. I understand that best is to show amp to technician, but I don't know if I should do it or just send amp back to seller and ask for refund.
Thank you very much!
Right knob not responding at all, doesn't matter which tube is being checked. Left knob (fine adjustment) works, but really strange, for ex: Indicator for V4 tube was showing that tube is under biased, then I turned fine adjustment clockwise - nothing. Turned counterclockwise a little and indicator told tube is ok biased (it should be opposite direction I guess? or It's inverted?)
Other tubes have exactly same behavior. But surprisingly amp works good I didn't find anything related to sound/biasing problem in it...
My question is - does bias adjustment system supposed to work like this? Or how it works in your amp? Please describe steps how you do it in your amp. I understand that best is to show amp to technician, but I don't know if I should do it or just send amp back to seller and ask for refund.
Thank you very much!
Hint: Volume knob has to be set to 0 otherwise procedure not works (at least for me). But bias adjustment knobs really work in opposite direction.