Tubes Asylum Questions about tubes and gear that glows. FAQ |
|
In Reply to: RE: NOS GE 211 tubes... Squeak on startup posted by bcowen on June 6, 2016 at 16:17:46:
The Ongaku does not push the 211 tubes very hard, idle current is about 60mA. Bias is a pain to adjust and I have only had it done by a tech - you need to put this 85 lbs amp on the side, use a high-voltage probe, etc - so only an authorized tech did this once for me. So I have not really used any worn tubes in the amp.
So couple more observations: The tubes look pristine as I said, very large getters, don't look burnt out at all. I have two other tubes which work fine: GE 211 that came with the amp, and new Kondo tubes. None of this produce the initial oscillation. Additionally the oscillation happens in the right channel even when I switch left and right tubes.
What I will try is switching around the preamp tubes (ie left to right). This is a bit harder as I have to remove the preamp tube cover, but I will try it when I have a sec.
This post is made possible by the generous support of people like you and our sponsors:
Follow Ups
- RE: NOS GE 211 tubes... Squeak on startup - miguelito 19:13:27 06/06/16 (0)