Audio Technica ATH-M30 Professional Headphones "swap left right speakers" Questions

...swap the right and left inputs to the transmitter base over whilst wearing the headphones. If the fault transfers to the other channel, then you have a faulty interconnect lead that needs to be ...

...to amplifier try to swap it between right and left speaker do the same to audio input jack (usually RCA jack). If it still works one channel only, probably the problem is in the power ...