Hi Tom
>
> Hi Mauri,
>
> > It's not a smart idea to neutralize a Gg amplifier because that
> > configuration is inherently stable and doesn't require it.
>
> That is not correct. There are many application that require
> neutralizing a GG amp. It is easy, cheap, and very reliable when
> done correctly.
Using modern and good ceramic tubes, the neutralization in Gg applications
is practically a complication and a waste of time.
I never seen any neutralization in professional and broadcast Gg amplifier
applications with 3cx800A7, 3cx1500A7, 3cx3000A7, 3cx6000 (YU148), 3cx10000,
3cx15000, 4cx1000, 4cx5000, 4cx10000, 4cx15000 etc. etc.
> > When a tube doesn't comply with the above statement and requires to be
> > neutralized also in a Gg, the plain solution is to change the tube to
> > another type or to swap into a cathode driven configuration.
Here I meant common cathode, not cathode driven.
> That isn't always an option. Some very good tubes have high
> feedthrough capacitance, like the 3CX1200A7 and D7.
Here you're right, but an high feedtrough capacitance is not among the
desiderable features for amplifiers.
After many attempts, I got convinced that one of the easyest applications
for the 3cx1200A7 is like an oscillator for industrial purposes.
The 3cx1200Z7 is instead a stable and useable tube, but of course the socket
had to be different.
>The 3-
> 1000Z, when operated above 30 MHz, also benefits from
> neutralization.
In my opinion 3-1000Z is a big scenographical glass bottle with a
respectable history, not really new neither a good tube (I mean compared
with the others available) to be used below and above 30 MHz in the third
millenium.
73,
Mauri I4JMY
> It really is not a problem when done correctly.
> 73, Tom W8JI
> w8ji@contesting.com
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