Re: Unused Unloved K2RIW Amp


Dear All,

With NOS valves, both 3CX and 4CX, I have found it helpful to run with heaters only for 24hours before applying high voltage; I understand that the getter on these is at the top of the cathode column and is activated by the heater- it cannot be activated by RF induction, as in glass envelope valves, of course.

I neglected this precaution, once- with one of a batch of NOS Eimac 3CX800A7s. Result, instant vaporisation of high voltage current limit resistor and destruction of valve. Following the procedure described above for the others in the batch, I had no failures.

I’m no valve expert, so experts please correct me, if I’m wrong.


Alwyn G8DOH


Alwyn Seeds, Director
SynOptika Ltd.,
114 Beaufort Street,
SW3 6BU,

SynOptika Ltd., Registered in England and Wales: No. 04606737
Registered Office: 114 Beaufort Street, London, SW3 6BU, United Kingdom.

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