[sdiy] CV outputs from 3.3V and 5V uC systems

Benjamin Tremblay btremblay at me.com
Wed Sep 16 16:03:35 CEST 2020


Most of the time a negative pitch bend does not net a negative voltage. Sample arduino code handles this summation in software before it hits the DAC. 

> On Sep 16, 2020, at 9:57 AM, MTG <grant at musictechnologiesgroup.com> wrote:
> 
> Pitchbend is what I was curious about. Is it safe to send a negative voltage to a (summer) in another module? I don't have experience with this, but if a CV (elsewhere) needs to be only "bent down" using this module, how is it done?
> 
> GB
> 
>> On 9/16/2020 6:04 AM, Roman Sowa wrote:
>> Hello Spiros and list,
>> first of all, you don't just put "any off the shelf DAC" in a decent MIDI2CV converter. If you want 10 octave range then too low power supply is the least of your challenges.
>> 
>> my advice is:
>> 1. yes, this is the best way. Do nothing and have 5 octaves (or more like 4.5) with some usability
>> 2. if you really want to go that way, there are full-contained power boosters, even making +/-15V out of 5V, in a form of small SIP device, or even SMD chip. Just add some additional filtering and you're done. It will have noisy output, but it's so easy to have whatever voltage converter nowdays.
>> 3. negative CV range is useful when someone wildly twists pitchbender at the lowest note. But -3V seems like overkill. OTOH who told you it cannot be -10V to +10V. Everything has its uses, pitch CV is just one example. In fact you could make it switchable like +/-10, +/-5, 0..5, 0..10, -5..10, -10..10 etc.
>> 
>> You don't need 100mA for that. If you think you do, search for another parts. I'd say more like 10mA is your goal.
>> 
>> Roman
>> 
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