[sdiy] paia midi to cv

[Grant Richter]

The problem is the 9700 VCO, not the MIDI to CV.

Remember, this is an inexpensive kit item, not a precision device.

I have tested twelve of the MIDI to CV converters. Of the 12, WORST  
case error was 10 cents.
This was fixed by replacing the DAC chip.

So the worst case error for the MIDI to CV should be 5 cents or less  
(typical).

The VCO only tracks 1 volt per octave over perhaps two octaves.

Set up the MIDI to CV using a 4 1/2 digit multimeter (if possible).  
That should get you to about 1% absolute accuracy.
(read the specs on your DVM).

Then just retune the 9700 VCO as needed for the range you are playing  
in.


On Feb 23, 2006, at 10:52 PM, Colin Raffel wrote:

> .2 Volts sounds like a lot for 2 to 3 octaves.  Are you saying that  
> you can get a perfect tuning range with a VCO tuned to your rogue?
>
> -Colin, who is about to wire up his first 9700...
>
> On Feb 23, 2006, at 11:26 PM, Jim Bob wrote:
>
>> I built the paia midi to cv a few years ago, and it wasn't  
>> precise.  I haven't measured it in years, but I believe for every  
>> 2 or 3 octaves it was off about .2 volts.  The paia instructions  
>> even tell you NOT to use a multimeter when tuning it, and to tune  
>> it hooked up to a VCO and do it by ear.  Maybe its because they  
>> know the results wont be precise?  I tuned the paia VCO's to be in  
>> tune  w/ this range, and it was fine.  now Im building new VCO's  
>> and other modules, and am wondering what to do about the midi to cv.
>> Is it usual that they are a little off like that?  Is it something  
>> I should worry about?  I haven't worked w/ other midi/cv devices,  
>> so dont know how exact it should be.
>>
>> thanks
>>
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