Anyone seen a DIY project like this?
E.g. STM32
The goal would be to eliminate extra OPAs after DAC, and noisy pots.
The amp should be hiss free anyway at low volumes, so why not do it in digital domain.
E.g. STM32
- i2s in and out,
- with analog pot as volume controller,
- with log volume profile in software.
- an extra would be a compressor using DMA
The goal would be to eliminate extra OPAs after DAC, and noisy pots.
The amp should be hiss free anyway at low volumes, so why not do it in digital domain.
can't you do that at the source of i2s if itnis a streamer?
squeezebox touch does this really nice. you can get i2s and spdif output with volume control.
squeezebox touch does this really nice. you can get i2s and spdif output with volume control.
see here, with ESP32 which is like STM32 but with WiFi and BT
https://www.patreon.com/posts/2-varianta-i-rg-90250980
https://www.patreon.com/posts/2-varianta-i-rg-90250980
Source is switched between various sources USB i2s/TV spdif/BT spdif, would be nice to have a master volume, maybe even trimmed volume for each source, then master volume.can't you do that at the source of i2s if itnis a streamer?
squeezebox touch does this really nice. you can get i2s and spdif output with volume control.
Almost every DAC chip has a built-in digital volume control, conversion from analog pot -> I2C control would be trivial e.g. with arduino.
This can likely be done with a $22.00 PSOC4 development board as it has configurable digital to create in and out SPI ports (can function with I2C protocol) and the A2D converter to read that pot.
There's subtlety to how to code the volume control though, especially if you want gain as well as attentuation and don't want artifacts.
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