It does look like an ecc99, but it came from a collection from 50’s-70’s
Wasn’t ecc99 a rather recent tube?
Wasn’t ecc99 a rather recent tube?
Measure the Htr current at 12.6 VAC. And trace the pins out. Could be base 9A or 9AJ (9AJ has no center tap on Htr, but a shield on pin 9 instead).
Then comes testing for gm and Mu.
Then comes testing for gm and Mu.
Any tube that I come across, and it's missing it's ID, I toss in the trash.
I don't ask anyone what it is (you'll get endless speculation) and I don't want to gamble on that sort of thing.
I don't give two craps what it "might" be.
I don't ask anyone what it is (you'll get endless speculation) and I don't want to gamble on that sort of thing.
I don't give two craps what it "might" be.
Thank you all for your insight.
I came across this tube in a large collection that was gifted to me years ago.
It has bugged me as i have not been able to identify it.
And just because I don’t know what is is doesn’t make it garbage.
I came across this tube in a large collection that was gifted to me years ago.
It has bugged me as i have not been able to identify it.
And just because I don’t know what is is doesn’t make it garbage.
I measured resistance between pin 4 & 5 as 6.7 Ω and pin 9 to 4 or 5 is 3.6 Ω
So it appears to be 9 A base.
Thanks for looking
i also get those unmarked tubes a lot, what i do is to look for very similar tubes that i know the use for....
you can even trace the pinout yourself and compare that with your known tubes, and of course testing those out in a real circuit to confirm...
any tube that has not gassed out deserve a second chance....😎