29 Aug
2008
29 Aug
'08
2:14 p.m.
>>>> "Tony" == Tony Duell <ard
at p850ug1.demon.co.uk> writes:
Chuck> Were these the special "space charge" tubes? e.g. 12J8, 12U7,
Chuck> 12DK7, 12DL8, 12CX6, 12DE8, 12CN5, 12BL6, 12DS7, 12AC6, 12AD6,
Chuck> 12AE6, 12AE7, 12AF6, 12AJ6 or 12AL8 (I've probably left out a
Chuck> few)?
> I don't recognize the term "space
charge". They were tubes
> explicitly specified in the data sheet for operation with 12 volt
> anode voltage. Almost certainly they were Philips -- EFnn and
> ECHnn for suitable integer nn... (I did that project in Holland.)
Tony> I think nn=83 :-). I am really digging into the depths of my
Tony> memory, but I seem to remember the ECH83 (triode hexode
Tony> frequency changer) and EBF83 (double diode and pentode). Maybe
Tony> at least one other type too.
Sounds right. I don't remember EBF83, I thought I had a semiconductor
diode for the AM detector stage. So that would have made an EFnn IF
amp.
paul