With one side of the cathode tied to the heater? (GS-35b, GI-7b, etc) sure
looks like rf on the heater to me...Some builders report ac modulating the
cathodes of Russian tube designs/conversions caused by the filament supply
when using two tubes. www.nd2x.net/w4emf.html. lists this problem and cure
during his conversion of a Dentron from 572b`s to a pair of GI-7b Russian
triodes. This is worth reading for anyone building a pair of GS-35b`s,etc.
Jim.
----- Original Message -----
From: "R.Measures" <r@somis.org>
To: "Tony King - W4ZT" <amps@w4zt.com>
Cc: "AMPS" <amps@contesting.com>; "Tomm Aldridge" <KD7QAE@ARRL.NET>
Sent: Sunday, March 06, 2005 3:02 AM
Subject: Re: [Amps] Alpha 77Dx -Adding Grounded Grid Filament Choke
>
> On Mar 5, 2005, at 5:23 PM, Tony King - W4ZT wrote:
>
> > Tomm,
> >
> > I believe that what Rich is saying here is that we should treat the
> > GS-35B just as though it were a directly heated cathode when dealing
> > with the question of protection for the cathode and heater circuit. A
> > bifiler choke with a center tapped filament transformer
>
> Even though a CT filament winding is required for
> filament-type/directly-heated-cathode tubes, I don't see the necessity
> for heater-type/indirectly-heated-cathode tubes since the heater
> potential is not in the signal path like it is in filament-type tubes.
> ...
> > ... ... ...
>
> Richard L. Measures, AG6K, 805.386.3734. www.somis.org
>
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