Hello John:
Well, I sort of do have experience. I built a home built copy, which I used
for many years. It is a reliable amp, but there are some considerations.
First, the plate dissipation of the 813's are 125 watts each. Total 250
watts. This is a pretty conservative rating, and putting air on them helps.
My amplifier actually used 3 tubes and I kept it at about 600 watts out, but
could get 750 - 800 easily. Never failed.
Second, this was designed during the tube era and there is no cathode input
filter. So, there is a lot of variation in load to the transceiver. A
tuned input would be a good addition, or you could use an auto tuner next to
the input, or you could use a manual tuner just before the input.
Third, there is no antenna chanceover relay, so you need to do your own.
The 813 tubes will be available long after some of the modern tubes
disappear. That is the problem with these modern wars, they do not provide
us with ham equipment for the next 60 years. WWII was the last great ham
supplier.
73, Colin K7FM
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