[TenTec] AF filter mod in Century 22

[Josh Gibbs]

Hi Garry,

I have C22 number 68!

Have a look at this:
https://drive.google.com/file/d/1ZMjJoC9GQkRfRBUEicwEodOghOthEyNd/view?usp=share_link

Look at the section "Modification center frequency of audio filter" near
the end.

Hope to have a C22-to-C22 QSO with you some day.

-Josh WU7H


On Tue, Mar 28, 2023 at 2:22 PM Garry Nichols <garrnich at gmail.com> wrote:

> I have an apparently fairly late Century 22 (serial #666) and the AF filter
> seems to peak around 750 Hz.  This does not set well with my old ears and I
> know that some of the early rigs came from the factory with .0033uF caps in
> the filter that set the center frequency to around 500 Hz.  My rig has the
> .0022uF caps which are the specified mod for 750 Hz.
>
> I was thinking of changing the .0022uF to .0033uF and was wondering if
> anyone knew if this created any problems in addition to lowering the
> frequency.  No point in doing this if I end up undoing it!
>
> I guess I could also set the value somewhere between but it would seem that
> I might tack in some .001uF as a trial for about 500 Hz.
>
> TU ES 73,
>
> Garry WA1GWH
> near Syracuse, NY
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