Thanks for the info so far guys...

It seems like the bias being incorrect would make it sound like poop, not fry tubes, especially since another almost identical tube soldiers on with no trouble...

But, I mostly don't know crap when it comes to electronics... that's why I'm asking here ...

Here's exactly how it went down...

The amp had chinese tubes.
I played like that for about 4 months.
I switched to Sovtek tubes.
About a month later (total playing time of about 20hrs), the preamp tubes died.
I replaced them with Sovteks.
About an hour later, they died.
Thinking ...

Anybody else?

Thanks for the links!

The 100U doesn't use the EL34's though.

I'm not sure if it makes a difference in the transformer it needs or not, but when this unit was working properly and sounding great, I was running 12AX7LPS's and 6L6WXT+'s.


Thanks again!
Steve

Hey guys... I'm just a newbie to the forum, but I have a tech question.

I have a Sovtek Mig 100U, that I absolutely love, but it apparently developed a transformer issue (no, it doesn't turn into a robot!).

It's strange... the amp still works fine, with Chinese preamp tubes.
If I put Sovtek ...