I want a build a dual 4cx1500b amplifier. I managed to obtain a batch of
unmatched 4cx1500b's all different date codes.
I was wondering which method would be best to achieve matched and balanced
tubes? Since the cathode is tied to one side of the filament i cant use a
cathode resistors to equalise currents. Is there a drive configuration that
would allow me to drive these 2 tubes without worrying about matched tubes?
Assuming there is no drive configuration that will achieve this, would it best
to use seperate bias supplies to try and equalise each tube individually?
Someone suggested that i use the Super Cathode Configuration, is there any
merit to this configuration.
I have looked at G3SEK regulator board kits, it seems these boards require
matched tubes. I would also like to DC ground the screen and these boards dont
appear to support grid driven DC grounded screen. I think some of these tubes
might be down on emission so would like to use max screen voltage at 400 volts,
however the screen capacitors on the SK800a sockets are flaky over 300 volts.
I am not familiar with the procedures for matching tubes, can someone explain
what the exact procedures are for matching transmitting tubes DC and RF wise. I
assume that resting equal grid current would be the indication of a close
match. Or is there more to this than meets the eye.
Appreciate the Help
Greg
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