>I built around a single gs-35b and so far all I see is a very stable tube.It
>takes a bit more drive than a 8877 on hf but seems to be very durable.
>I did take the time to condition the tube and have not yet had any
>flash-over during operation. I`m in the process now of adding a second tube
>to this deck.
>I use anti-parasitic devices in all my amps,In my 4-1000`s (2 tubes)
>supression in the cathode side works better
** Since the cathode is the destination of the feedback-C in g-g
configuration, adding a vhf-damper to gnd from each filament pin makes
sense since the cathode is where regen must begin. For a 3cx1200A7 (C-fb
= 0.8pf), a 10-ohm MF resistor in series with 33pF to gnd serves to
absorb vhf energy that is passed back (from the damped wave ringing in
the vhf-resonant anode circuit) by C-feedback. Ideally the Xc in the C
cancels the XL in the tube's internal leads at c. 90MHz. However, this
is obviously guess-work since one can not enter the envelope to measure
XL. I guess one could call this an educated guess.
>...
- Rich..., 805.386.3734, www.vcnet.com/measures.
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