ECF80 spec.

[Phil Y]

Hello all.
I have just bought 4 ECF80s from Matthew. 2 to use and 2 spares for my KEL84 as the original EIs are getting tired.
As I have one, I put them on my valve tester. 3 of them measure fine (about 20% variation from spec.) but one does not look so good. The triode half measures 6.2mA Ia (spec. 14 mA) although the Gm looks OK at 4.5 (spec. 5.0)

Would people say I should return this as duff ?

The pentode half has good Ia but the Gm is a bit low:
7.4mA Gm3.8 (spec. 7.0 & 5.5)

Thanks, Phil.

[Richard]

Hi Phil, yes it looks weak. You'll know these are a bit notorious for being variable but the triode section in partic should be better than that

[Phil Y]

Thanks for that Richard, I will contact Matthew with the bad news.

Phil.

[Phil Y]

Just to say, all sorted now.
Thanks Matthew & John.