[sdiy] Doepfer DIY Synth

[Harry Bissell]

if anyone likes to use Zener shunt regulators for 
front panel pots (I do)... I suggest you use 5.1V
zeners as the temperature coefficient is the best at that
value.  Values farther away from 5.1 get progressively 
worse.

(of course you could use a shunt reference chip like the
LM4040.whatever

H^) harry




----- Original Message -----
From: Simon Wilson <simon at bigpink.co.uk>
To: Neil Johnson <neil.johnson97 at ntlworld.com>
Cc: Synth-diy at dropmix.xs4all.nl
Sent: Tue, 06 Jul 2010 11:31:07 -0400 (EDT)
Subject: Re: [sdiy] Doepfer DIY Synth

Hello Neil

The power supply I propose using has a 12v for the main circuit and a 5v
supply for these CV inputs. Does this sound OK? 

Simon 

>Hi,

>If I may suggest ...

>"(attenuating the power rail)"

>A more stable solution is to use a stabilised reference.  A
>quick/cheap option is a 10V zener (assuming a 0-10V input range,
>adjust zener voltage according to taste).

>That way you isolate the CV inputs from any variations in rail voltage.

>If you already have supply rail wiring to each pot, then a minimal
>change per pot is the addition of a series resistor (say, 1k0), a
>zener (10V see above) and optionally a 100n smoothing cap.  Or just do
>this on one pot and bridge across to the other pots in parallel
>(beware of loading, but in the above case should be OK with 1k0 load
>resistor).

>Cheers,
>Neil
>-- 
>http://www.njohnson.co.uk
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-- 
Harry Bissell & Nora Abdullah 4eva