DAC scale factor for 1V/oct

[Magnus Danielson]

From: John Speth <JohnS at molectron.com>
Subject: DAC scale factor for 1V/oct
Date: Fri, 21 Jul 2000 11:23:27 -0700

> I'm now designing the DAC portion of a simple MIDI-CV design.  I need to tap
> somebody's experience in how I should control the scale factor for the DAC
> to get a 1V/oct response.
> 
> The DAC requires a ref voltage.  I can vary this using a pot thereby scaling
> the voltage output.  Alternatively I can use a constant reference voltage
> and vary the output voltage at my DAC output stage by using a pot on the
> feedback path of the op-amp.
> 
> Which way is the better way to go?

For some odd-ball reason there are such things as 5.12 V and 10.24 V voltage
reference out there. Take the REF-01 from Analog Devices for instance, is
easy enougth to use for this purpose, a 100 k trim-pot added and you can trim
this baby up. I would try to do it thst way...

Cheers,
Magnus