Hi, i'm considering building a O2 amp, and was wondering if anyone knew if it was possible/simple to put a 1/4" headphone out on the PCB instead of the 3.5mm one.
no there is no way to put a pcb mounted 1/4" in place of the 1/8 they have different scale obviously, but you can for sure panel mount it and run wires to the pads.
btw theres a headphone section, this is for speaker amps