Master volume


I’m excited to try out Zynthian, currently waiting for the components to arrive. One thing I’m missing is a master volume control, is there any support for this in the software or should I just wire a stereo potmeter after the DAC?

The webconf allows you to set the Alsa audio volume.
If you bought an AudioInjector (Zero), you have the option to solder a potentiometer as well.

I am using either Midi volume pedals, CC7 slider or audio pedals.

I have too much respect regarding noice that prevents me to solder something into the audio chain.

But there might be others with experience that can tell you the parts you need if you have a Hifiberry.

LOL!!! You’ve never opened some way_too_expensive_high_end_audiophile" audio modules, have you? :rofl:

:slight_smile: I knew I get a response to that quote.

I desoldered a connector from a hifiberry. I thought I was careful. Now it has unpredicted noise sometimes. Like xruns, that my Audioinjector setup doesn’t.
That’s why I am careful.

I’ll just wire a 10k potmeter between the RCA and jack connectors. As long as I keep it at maximum it’s just a 10k parallel resistor, this cannot affect the audio quality.

By the way have the designers considered replacing the all-in-one board with a microcontroller (e.g. arduino, esp32)? This could handle the rotary encoders and send updates over SPI at 50hz, not wasting CPU cycles on the raspberry pi. As a bonus this would give a couple of ADCs, one to control master volume :slight_smile:

Anyway I’m geting ahead of myself, I should build my box first.

This would be nice, of course … but currently, zynthian’s hardware design 1st priority is simplicity and ease of building. Currently, having a uC would add too much “building” complexity for many people that would like to have a Zynthian Box.

Of course, we could update the uCs firmware from the RBPi and this complexity would be partially hidden, but this will add more complexity yet to the circuit/PCB. Probably, this will be the future of Zynthian, but this kind of development is not a priority right now.

Anyway, you are very very welcome to advance in this direction. If you do so, i would help you as much as is can :wink:

Kind Regards,

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I can understand. Thanks for creating and sharing this project! I hope to contribute in the future.

Alright, it’s working! ALSA master volume control using an STM32 microcontroller connected over USB :sunglasses:

Documentation and software is available here:


well, master volume knob is one option, but i noticed that if i change the volume on a loaded preset to let’s say 30, the value jumps back to 100 when another preset is loaded. i didn’t had time yet to dig inside the whole thing (really newbuild newbie :stuck_out_tongue: ) , how the presets are build etc. but the solution has to be simple (what would bob moog do?)

Yes I’ve seen something like that…
You can end up driving the volume down and down on each new load.