It`s my common practice to have a 50k (Or so) resistor in the negative lead
shorted by a relay during transmit...I find this to be less tramatic to tube
stability in my amps as opposed to totaly opening up neg on standby....Works
for me...Jim.
----- Original Message -----
From: "craxd" <craxd1@ezwv.com>
To: <amps@contesting.com>
Sent: Friday, September 17, 2004 9:32 AM
Subject: Re: [Amps] input matching question on the YC156?
> Bill,
> In any amps I've made, I did kill the B- lead for the HV until the
> antenna relay pulled in even though it was biased to cutoff on idle. The
> reason being is that if the bias ever failed while the amp was at idle,
> you'd have a run-away situation that would happen fast. On tetrode amps,
> the screen has to be killed with the B+ plate. This is an extra I always
> did but the cost keeps the manufacturers from adding it. This will also
> kill an amp that might be prone to self oscillation on idle. I'm not
> saying that what they do is a design flaw but I'd like to see all of
> them include it.
>
> Will Matney
>
>
> Is this true even when the tube is biased into cutoff? I've owned
> four commercially-made amps and all of them apply HV as soon as the
> power switch is turned on, but all four have the tube biased into
> cutoff. Are you saying that is a design error?
>
> --
> Bill W6WRT
>
>
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>
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