(buy a) A wired computer ? Try shielding .. a bit of metal foil tape over the wire grounded to the frame will isolate RFI .
in Music gear a Mic cable shields better than a guitar cable , because the signal is the 2 +- wires inside the braided shield
the other the shield is also the - return wire of the circuit.
Last edited by fietsbob; 08-26-14 at 12:42 PM.