Tomm Aldridge wrote:
> This is an interesting thread to me not because of the AL-811 vs
> MLA-2500 but because I am designing and building an amp. If I
> understand this correctly, using a TS570 transceiver to drive my amp
> implies I really don't need a tuned input circuit as I can just use the
> built-in tuner of my rig to achieve a good enough match to the input of
> the tubes. That saves me money and complexity.
>
> However, some on this list advise that the proximity of the output C of
> the tuned input to the cathode of the PA is very important for its
> "flywheel" or energy storage effect during the wide swings in impedance
> during a cycle of operation.
>
> My question is, which strategy should one employ and what are teh pros
> and cons? Assuming, of course, a built in AT such as in the TS570.
>
> Regards,
>
> KD7QAE
> Tomm
There is a problem with using a built-in tuner with a grounded grid
amplifier. In a GG amp, the input and output are effectively in series.
The input impedance varies with both the amp tuning and the drive power.
This constantly changing impedance during tune up can drive a built-in
tuner crazy as it tries to match a constantly changing impedance. Often,
it will go through a couple of cycles and time out.
73, Roger
--
Remember the USS Liberty (AGTR-5)
http://ussliberty.org/
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