Adding a power jack to the Cigar (cracker) Box Amp

<August 6, 2010> This power supply configuration should only be used if you can find a positive tip power supply. Negative tip is more common in the music scene (effects pedals). General Guitar Gadgets sells a negative tipped power supply for $11. Check out this post for more info…Adding a power supply to a Cigar Box Amp (REVISED)

It must be noted that not any old power supply will work! Wall warts must be regulated at 9 to 12 volts and no more. A wall wart that is labeled 12 volts, 500mA can deliver up to 20 volts. Only after the current is close to 500mA will it be close to 12 volts. Please be cautious when using an unknown power supply. If you have access to a multimeter, please test your power supply before plugging it into your amp. The LM386 chips will fry in about 5 seconds of over-voltage.

If you’ve purchased, or made, a cigar box or cracker box amp and you want to add a way to plug a wall wart into it, this tutorial is the one for you. Adding a power jack is very simple.

Parts needed:
151555 power jack (Jameco.com)
Two pieces of wire (Length depends on where the power jack is mounted in relation to the switch and input jack.)

First, connect a piece of wire from the tip of the power jack to the junction of the battery at the switch.

Next, desolder the battery’s ground wire from the ring of the input jack and solder it to the power jack terminal 3.

Finally, connect the power jack terminal 2 to the ground ring of the input jack (where the battery’s ground wire was originally soldered).

Diagram including new power jack
Diagram including new power jack


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About robbie

I am an electronics enthusiest and a ham radio operator (W1RCP). I like to play with electronics. It's fun and educational. I looked forward to working in the engineering field in the future. I have a BS in Electronics Engineering Technology from DeVry University. I also have an Associate's degree in Marketing Management from Moultrie Tech, and a diploma in Electronics from MTC.

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