Hello ,
I'm looking for ideas.... I am using a QBL5-3500 amplifier on 2m. Untill
now , I have been using unregulated screen power supply with quite good
success , but since I've moved to a new place , my mains voltage is higher
than previously and my screen voltage went up to 1000v ( instead of 800v
recommanded for that tube) . Off course , it is possible to use a small
variac on the transformer primary , but a better idea would be to design
and build a 800V screen regulator , if possible , an high performance
design , like the one designed by GM3SEK in his famous " Tetrode Boards" ,
with the various protections needed..
But the tube is a little bit greedy ( or GRIDdy :0))
Screen voltage is 800V WG2 power is 100W maximum , so screen current can
go up to 120ma during normal operation. There is nothing said in the tube
data sheet about negative screen current , but there is no reason why it
cannot occur.
So I am looking for a design able to statisfy my needs. Maybe the GM3SEK
can be modified to run with that tube?
73 Dom/F6DRO
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