[sdiy] Precision voltage offset

[Ken Stone]

Have a look at:
http://198.164.142.50/~cgs/modules/mixer.html

Feed the cv directly into one of the inputs without the pot. Tye one ind of
the pot shown to the positive power rail, and the other to the negative
instead of earthas shown. The pot can then be used to give any offset you
like. The resistor between A and B could be replaces with a 100k pot to give
you gain adjustable between 0 and 2, though as shown should be at exactly 1
(maintaining the scale). 
I have been using this actual module as shown in the photos to do DC offsets
for my VCO for years.

Ken


>I've been looking around for some circuit examples and have had little luck
>and I just dont have the knowledge to do this without working from example.
>( I can build anything, designing on the other hand is more problematic,
>unless I can work the Lego approach or its digital )
>
>I'm trying to offset a CV by a set amount.  Offset it down in fact.  The
>idea here is to offset F0 to 0 volts so I can use a standard Midi/CV with
>my Moog without having to patch it to a keyboard and use its transpose
>feature.  ( yes, I'm on the same quest I mailed about a month or 2 ago ).
>
>If someone has a circuit for this, would be great. Give me something to do
>tommorrow unstead of watching whatever marathon is on TV and cursing about
>eMagic logic...
>
>-- 
> ------------------------------------------------------------------------
> - Tom Arnold -       When I was small, I was in love,                  - 
> - Sysabend   -       In love with everything.                          -
> - CareTaker  -       And now there's only you...                       - 
> --------------         -- Thomas Dolby, "Cloudburst At Shingle Street" -
>
>
_______________________________________________________________________
Ken Stone   sasami at hotkey.net.au  
Modular Synth PCBs for sale <http://www.blaze.net.au/~sasami/synth/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>