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[AMPS] Dumb directly heated cathode amp operational questions

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Subject: [AMPS] Dumb directly heated cathode amp operational questions
From: billp@wwpc.com (Bill Putney)
Date: Tue, 6 Jun 2000 15:31:40 -0700 (PDT)
OK, I'm new to using HF amplifiers. Here's some rudimentary questions for
everyone. I just bought a Henry 2K-4. It has 2 3-500Z's inside and the blower
makes a fine noise. Not noisier than we have a right to expect but noisy none
the less.

My inclination is to use the amp when I can't make the contact otherwise.
That's what the rules say and I'm fine with that. I'll leave it off 90% of the
time and turn it on when I need it.

1) The Henry manual doesn't say how long to leave the amp on before transmit.
Some places I've read that directly heated cathode tubes are ready to load
after 3-5 seconds. Is that reasonable for this amp? What is?

2) After I've been running the limit in an SSB QSO what's the recommended cool
down period before I shut the power off?

3) For those of you who run 3-500Z amps, do you turn the amp on and off
frequently when operating at one sitting? I'd be concerned about thermal shock
to the filaments shorting the tube life if I made a habit of this. But is sure
is noisy...

4) Would a blower control relay that started the blower on transmit and turned
the blower off (or down) after the cool down period work. Is there some reason
to have the blower on when there is no current through the tubes to heat things
up? That would allow me to not cycle the filaments just for the sake of getting
the noise level down. I could even set up this blower control circuit to run
the blower the cool down period after I turn the power switch off.

Or B) am I just obsessing and I'll never notice it after a while.

Thanks, Bill

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