[Amps] Input Circuit

[KD7QAE]

Since you are going to all the effort to build an amp, why not build in 
the input filter?  The GS35B does not present a constant input impedance 
of 50 ohms and the input filter can act as an integrator that "smooths" 
out the effect.  It certainly can't hurt if done correctly, and it could 
help the quality of your signal.

I purchased the parts for mine from RF Parts for <$40 (ARCO compression 
trimmers).  Search the archives for more information on this topic, 
there is lots to be learned regarding placement, sources, and such.

Tomm, KD7QAE

Jennings wrote:

>Hi all
>I am currently building an HF amp using a GS35B. It would appear that the input impedance is around 50 ohms + or - and most circuitry that I have seen does not use a tuned input circuit. I have plenty of drive from the FT1000D available.
>
>Any pros and or cons one way or the other?
>
>Lee ZL2AL
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