Home Tubes Asylum

Questions about tubes and gear that glows. FAQ

Re: Newbie with tube problems (long)

Hello Steven and thanks for your answer.
My amp was delivered with a matched quad of EL34's but now that I have changed the left side pair it might no longer be properly balanced. The amp is supposed to have automatic bias though, separate for each power tube, doesn't that correct the imbalance?
For the 6922's, they should also have been delivered as a matched quad. but I haven't had them checked...
I don't know if the amp has what you call a "long tailed" phase splitter, according to the designer it has a "selfbalanced phase inverter" followed by a "push-pull driver where the cathodes are connected together" (free translation from Swedish).
When you say that you suspect a gross inbalance, do you mean that one of the 6922's has two halves that are not properly balanced? Would changng one 6922 for the other in the left channel (i.e. PI becomes driver and driver becomes PI) show if that's the case?
I have checked the cabling and have found no shorts. I don't have any fuses inside the amp either so that's not it.
I'm not too confident with my soldering though: Say one of the joints to the tube socket was badly made, could that cause the behaviour I see? Wiggling the tube would create a better contact? But why then only when the amp becomes hot?
Tubes are still a mystery to me but thanks for taking the time to explain!
Cheers,
Mikke


This post is made possible by the generous support of people like you and our sponsors:
  Kimber Kable  


Follow Ups Full Thread
Follow Ups
  • Re: Newbie with tube problems (long) - mikke 10/11/0122:46:48 10/11/01 (0)


You can not post to an archived thread.