[Amps] Operating a tetrode amp at very low power.

[Lukasz]

Thank you for answering Val.

I was more concerned about possible signal quality issues. Nonlinearity etc.

Regarding the things you mentioned I think they are acceptable to me.

The plate voltage is indeed 3000V and the idling current is about 350mA .
There is also about 100W for the heater and 200W of losses in other parts
of the amp so it continously uses about 300W when not transmitting and
~1400W when transmitting regardless the power.

However , the electricity I use to power the amp is essentially free for
me. In all other seasons of the year than winter my PV generates a surplus
of energy. So I don't dare about extra 2kWh per day  every few days.

During winter on the other hand I'd be running a 2kW electric heater in my
shack(so I'd use it anyway). Instead I have a choice of running the amp.

As for wasting the tube's lifetime. This may very well be a real concern
for some of ubes, but my amplifier is a part of an old military radio. The
tube (gu-43b and one I use Q1p/42 has lifetime long enough I'm very
unlikely to ever use it up. (especially that I have a spare). This tube was
often used running at full power for years either relaying a dozen
telephone channels(FM modulated) in its military role or being a part of a
TV transmitter.

73, Łukasz

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