3 Prong Power Cable (No ground switch) Mod

Amplifiers contain voltages high enough to Kill you even after the amp has been powered Off !!! If you don't have enough electronic experience to identify and discharge the Filter Capacitors which contain these Deadly voltages, take your amp to a Qualified tech. If you don't know a qualified tech in your area, post a request in the alt.guitar.amps newsgroup, the folks there will be happy to help you.

The Mod:

If you can imagine what it might feel like to pick up your guitar, play the opening melody, lean forward into the mic to sing the first line, and then ZAP !!! A blue spark hits you right on the lips with 110 VOLTS !!! This scenario and possibly even deadly consequences can be the result of floating grounds caused by the old 2 prong style power cords that came on 50's and 60's era amps. This is a very simple mod and if you're worried about keeping your amp original, just keep the original cord in the closet.


1. Note the position of each lead and remove old wire. (Put it in a plastic bag, and put it away in your closet for preservation).


2. Purchase a new 8' to 10' heavy duty 3-wire (grounded) power cable and a plastic strain relief strap from any good amp parts supplier.


3. Strip away about 6" of the outer insulation and strip about 3/4" off the end of each wire.


4. Solder a round lug to each of the 3 wires.


5. Attach the green wire(ground) to the nearest transformer bolt you can find.


6. Attach the black(hot) and white(neutral) wires to the same positions where you removed the original black & white wires from.

*NOTE* If your 2 prong power cord amp has a Ground Switch, you must also disable this switch for Safe operation of your amp. For instructions, see the "Ground Switch Mod"