Cut the jack off of the 1/4-inch stereo cable with the tin snips.
Remove the sheath on the 1/4-inch jack by unscrewing it. The sheath is the metal below the plug that covers the wiring.
Slide the sheath off of the wire.
Remove both wires connecting to the 1/4-inch jack.
Cut the female jack from the XLR cable using the tin snips. Discard the female jack; the male jack at the other end of the cable will plug into the mic.
Remove the insulation wrapping all three wires using the wire strippers.
Remove the insulation wrapping each cable. Cut off about 4 inches of insulation.
Slide the 1/4-inch sheath over the bare wires.
Position the XLR cable so that it is in the position it would normally be when plugged in, with the clip facing down. The left and bottom cables carry audio. The right cable is the ground.
Solder the ground cable to the sleeve of the 1/4-inch jack, which is the upper part of the jack where one of the cables originally connected.
Solder the audio cables to the stem that extends from the jack.
Wrap the ground cable and audio cables in electrical tape individually, making sure they do not touch. If they do, this will cause a short circuit and your cable will not work.
Screw the sheath onto the 1/4-inch jack and wrap any remaining exposed wire in electrical tape, again ensuring that the ground and audio cables do not touch.