Friends!
I have a couple of days got a home-built amp
using a 3CX1000A7 - it deliver around 1200 watts
out, key down - only tested it on 80 meters.
It seems that it's built, in the seventies, with
input circuits from an SB-220. As I think that
the input impedance for a 3CX1000A7 is around
50 ohms can the use of SB-220 input circuits
be OK? I don't have the input impedance of
a pair of 3-500Z's here and have not tested the
3CX1000A7 with an SWR-meter between the
tranceiver and the amp.
3CX1000 is about 42 ohm and 3-500Z about 115 ohm,
so inputs for 2 x 3-500Z will work just fine, just
would need a slight tweeking, i e will make about
57.5 ohm.
I know Rich will object to this (by the way
your letter Thursday Rich) but how about
not using any input circuits?
I will also strongly object! Please do not run a
cathode driven GG amp without input matching, we
have enough wide signals on the bands already. It
will degrade IMD performance very much.
Thanks in advance for answers and 73 de
Osten SM5DQC sm5dqc@areteadsl.se
73 Jim SM2EKM
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