Can i change the main volume of the mp3 trigger

Can we control the main volume of the mp3 trigger with 2 externally mounted buttons?
Volume up and volume down.

I see that you can control each mp3 with the software in volume but it is the output volume of the headphone that we want to control.

Thank you

Serge Van Son

@TS-Russell The hookup guide link on the product page is coming up 404.

Both on the product page (main & documents) are working for me; maybe sparkle was down earlier…re-try? MP3 Trigger Hookup Guide V24 - SparkFun Learn