"AJ Lake" wrote in message
...
Bob wrote:

I also find that it's much easier and cheaper to go
QRO with valves than it is with semiconductors.

Yes tubes are still quite valid in ham amps.

TV sweep tubes powered many of my HF amplifiers over the years!

Remember those sweep tube KW amps? What was it, 6 tubes in parallel?

I think my old Swan 350 (nicknamed Swan 3-drifty for good reason) used
sweep tubes. Kept within specs they lasted a long time but they didn't
seem to take much out of resonance abuse.

And my Heath mono-banders, wasn't that a sweep compactron?
Yup

Yes I was a sweep tube fan also...

At one point, sweep tubes were available cheaply at TV shops so the designs
were at the edge of meltdown. It was neat to have a 350w pep radio, but
that was asking way too much. I saw a lot of Swans and others that would
break into oscillation with the least provocation. I knew one guy who was a
regular customer of the Radio Shack Lifetime tubes. Give me a set of
6146s any day. Conservative designs yet economical. I can always follow up
with 811s for more power. Those guys are still cheap and seem to last
forever. If you have to plug it in the wall anyway, might just as well be
tubes.