so, i got a cable = stereo 1/8in to mono 1/4in , stripped the EQ off a tone on my amplifi 150 and .. they appear to be identical volumes and nearly identical level of clarity. this was comparing it against bluetooth input and 1/4in guitar input.
if i increase drive on the guitar channel it does give more volume, but at the sacrifice of clarity.
this was a waste of time getting the cable and etc. just use rear 3.5mm aux or bluetooth stream
thanks
AC