[sdiy] Quantizer DAC or PWM?

Roman Sowa modular at go2.pl
Tue Dec 20 11:05:29 CET 2022

35ns CV settling time is thousands times faster than any human's perception.
 From my personal experience, any CV change shorter than 5ms sounds like 
continuous glide.


W dniu 2022-12-20 o 09:49, brianw pisze:
> I've always had good luck with external ADC and DAC. The internal ones are "convenient" but prone to picking up noise from the processor.
> I'm curious, though. With so many people talking about lowpass-filtered PWM, what's the settling time between each new value? I suppose that's equivalent to asking what the maximum sample rate. I have worked with external DAC chips that have a settling time of 35 nanoseconds. I can't imagine the time constant for filtered PWM to be that fast.
> On the other hand, if you want to implement portamento, then having a voltage-controlled filter on the CV output would be a feature.
> Brian
> On Dec 19, 2022, at 7:19 PM, Jay Schwichtenberg wrote:
>> I'd go with a 15-16 bit external high quality DAC. Internal ones usually aren't high quality. I'm not a fan of using a PWM DAC for something like this. If you want a DAC that doesn't need to be fast or precision then PWM is ok. Also use a precision voltage reference for the DAC reference, not the digital power supply.
>> On 12/19/2022 1:55 PM Didier Leplae wrote:
>>> If I understand correctly, the ESP32-s3 got rid of DACs but previous versions had them. I was a bit surprised not to find any
>>> On Dec 19, 2022, at 4:59 PM, The SynthiMuse wrote:
>>>> Literally today, I just received my first esp32 dev board to build :
>>>> https://www.google.com/amp/s/www.instructables.com/Extremly-Simple-Oscilloscope-Clock-With-ESP32/%3famp_page=true
>>>> I was under the impression that the standard esp32 had native DACs.
>>>> Am I wrong?
>>>> Gerry
>>>> On Mon, 19 Dec 2022, 16:14 Didier Leplae wrote:
>>>>> I’m working on developing a quantizer module for eurorack. I made a previous version using a PIC chip with a DAC which I abandoned during the chip shortage.
>>>>> Now I’m looking at taking up the project again but possibly with an esp32-s3 chip instead. This chip only has PWM, though.
>>>>> Question is whether PWM with smoothing circuit is it accurate enough for a quantizer? Does anyone have smoothing circuit to recommend?
>>>>> Or is a DAC the better option?
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