I think this has something to do with power output. As it is louder while running via usb dac via neutron at max volume, along with having different tonality and wider stage in all dimensions.This is realy interesting. I personaly have found the p6p over usb input to be quite a bit behind compaired to internal storage. That wad improved quite a bit with even a fairly cheap isolator (intona) but it's still behind local file imo. This is especialy noticeable when using the p6p into some of my higher end desktop amps (though maybe that's not super fair to a dap tbh)
Did you try using Neutron? Other wise, yes it is behind in my finings as well.
The Metal Magic Research Thummim.Just to be honest, I am not a fan of the c9. I feel the wa8, phantasy ii, and 428 all beat it rather handedly in technicalities. What cans are you looking to run?
I listen to loudly and I just feel the amp showing all sings of struggle past 57 HG . The harshness, the stage narrowing, imaging getting looser and smeared, etc.
Just to make clear, the volume output in terms of db is not what I find lacking, just the sense of power from having power in reserve I guess
I assume it has to do with Ibasso d312 I am used to having 6.9 V and p6pro 4.9.
So I am looking into something do give the sound slightly more density apart from sense of power and the traits that come with amping.