Didn't see your call sign but assuming you are building this for
licensed amateur service, here is one opinion. You cannot damage a
ceramic metal tube with too cold liquid, within reason. Two things may
limit you, one being freezing point and other being the dew point. If
you are in a humid climate, and happen to turn off the RF power, but
leave the cooling on, you may find significant condensation on the
surfaces within the amplifier, if it is below this point. We have done
this by accident at the particle factory, where we had chilled water
cooling a particular part (input circuit) of a big triode. With the
filament off, and no RF, there was no heat, so it 'sweated' inside the
cavity and was fireworks when the RF came back on.
On 3/14/16 10:00 AM, firstname.lastname@example.org wrote:
Date: Mon, 14 Mar 2016 21:46:45 +1300
From: Steve Wright<email@example.com>
Subject: [Amps] Ceramic tube temp too low?
I am thinking of liquid cooling VHF/UHF GS-35b tubes to dodge noisy fans
and and tuning drift.
But what will be the situation with operating these tubes at lower
temperatures? I cannot see that they have a rated operating range, just
a maximum seal temperature.
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