[sdiy] Anybody worked with real Moog System 55 ?

[cheater cheater]

potentiometer material has changed drastically over the last 4
decades. No reason to use carbon film anymore, especially for
something as crucial as oscillator tuning.

When you've cloned the VCO, see if you can recreate the phase jitter
of the reset time..

Cheers,
D.

On Mon, Sep 27, 2010 at 15:36, Jean-Pierre Desrochers
<jpdesroc at oricom.ca> wrote:
>
> Does anybody worked with real Moog System 55 ?
>
> I'm building a VCO driver which will be very close
> to the Moog system 55's  921A VCO driver design (parts & front panel).
> I'm wondering about the stability of Allen Bradley pots used in such a design in late 60's.
> I'm considering instead Vishay 249 series pots for FREQUENCY front adjustment
> but they only are capable of 295deg mechanical rotation compared
> to the original Allen Bradley's 320deg mechanical...
> This would have an effect on the front panel FREQ divisions
> (smaller span).
> Since Allen Bradley doesn't exist anymore I'd use PEC pots
> like this:
> http://media.digikey.com/pdf/Data%20Sheets/Precision%20Electronic%20Components%20Ltd%20PDFs/MIL%20Style%20RV4.pdf?cshift_ck=1830796695cs506374199&client_id=5042
>
> So my question is:
> Were the original Allen Bradly pots that bad
> about freq stability (carbon type) or this would still be
> a 'fair' choice to me today ?
> JP
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