Avin Avant3 DSP stops after a few minutes

[Andre]

Ok, just want to be sure that the app works fine. 

Well, we would check this via multimeter. 
Another option: read out the dsp via I**A, look at status if a source is set (Tuner) or will be set it you tap on "Tuner" in DSP-Mode of the app.
Also you see there, if it's on or not, etc.

And you may check there, if the DSP act like you change values in the app.