Thanks Alan; I should have added a bit more data: the valve has an International Octal (but it might be a Mazda Octal) base. It might even be a 6P25!
[Subsequent edit - by Al.:]
And upon comparison of the data for a 6P25 and an EL33, they are indeed very similar, electrically. And the base pin-outs are the same. I reckon someone has plonked in a 6P25 here! Oh, and yes, upon checking, this unknown valve does have an IO base, not an MO.
Al.
[Subsequent edit - by Al.:]
And upon comparison of the data for a 6P25 and an EL33, they are indeed very similar, electrically. And the base pin-outs are the same. I reckon someone has plonked in a 6P25 here! Oh, and yes, upon checking, this unknown valve does have an IO base, not an MO.
Al.
