Phat DAC and volume control

Hi. I bought a Phat DAC (PI62991), have not received it yet but I have a question.

Is there a way through software, when playing a sound, to control the sound level? Say, if I’ll play an MP3, is it possible through command line to adjust level of that sound, which will leave phat dac?

Thing is, my amp doesn’t have volume adjustment, and my speakers do not have it as well. There is no way I can put a mechanical potentiometer to be adjusted by hand (the box will be unreachable). I had high hopes, when I bought it, that I can use my own script to bring the sound level up and down remotely. Now, more I try to read, it seem impossible. Or am I not correct?

Thus, am I understanding correctly, there is nothing I can do to adjust the level through SSH command line?

PS: Also, as a second question, what is the best way to unite left and right channels into mono? Should I put resisters or diodes to make sure one channel does not feed back into another, or it is not an issue?

What software are you going to be using for playback? There are, for example, MPC commands to adjust the volume up and down

First, I’m sorry to resurrect this post.

I’ve one Phat Dac and I would like to control the volume, by software or hardware, between the Dac and the Amp.
I don’t find any post regarding the possibility to add a rotary encoder on the DAC.
I hope someone have already tried to do it with success.

For your question how to mix stereo channels to mono, there’re many schemas on the web.
BE CARREFULL : Never use a splitter to join two channels. You risks to burn your speaker or the amplifier.
This solution is very easy to solder :
I’ve exchnaged on the subject on :
and there’s an example with the Phat DAC.

Finally, if is it not possible to plug a rotary encoder on the Phat DAC, I will solder a 10K potentiometer between the DAC output and the Amp Input.

Looking forward to read you.