[Amps] Indirectly heated cathodes

Mark K5AM k5am at zianet.com
Sat Apr 3 21:17:21 PDT 2010


Roger, NR1J, wrote:

 >>> Has anyone experimented with using a lower "keep
alive" voltage to allow faster warm-up when full voltage is
applied? <<<

In my 2M amp I use a "Heater Idle" circuit. This does not
shorten the initial 3 minute warm-up, but later, if I do not
transmit for 5 minutes, then the heater voltage on the
4CX1000A drops from normal, 5.8 volts, to 5 volts. The
idea is that the 5 volts will not age the tube so much.
I sometimes leave the amp in standby all day. When I
transmit, the circuit recovers to normal voltage
automatically. Full details for the circuit, and notes on
recovery speed, are on page 19 of the article,  2mkw.pdf
posted for download on the page
www.zianet.com/k5am/amps/2mkw.html

Mark, K5AM



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