Tutorial: USB Power for Your Audiobag or Cart

Recently I have been exploring the need for more power in my bag so I built myself a BDS. Then I realized I have a few items in my bag that require a 5V power source. So I set out to make a 5V USB power adapter for my BDS. Sorry for the short intro into this tutorial. I’ve been swamped with shots and testing some new gear.

Things Needed:

Step 1:

I am using a “broken” 5V USB charger that I had been using in my car. The internal spring collapse and the input power button doesn’t make contact with the car socket anymore. BUT the circuit still works, so lets mod it!


So to begin the process you will need to unscrew the metal cap.


Step 2:

Peel back the sticker on the face and you will find 2 screws. Unscrew these and the clamshell plastic case will open up.


After the screws come out, you will need to pop the metal top cap off and the plastic clamshell will come apart into two pieces.


Step 3:

Make a note where the side contacts connect to the PCB. On my USB adapter it is on Pin 1 on the USB PCB board.


Step 4:

Desolder the Negative wire from the PCB. Use the wire snippers to cut the Positive metal contact. Make it look like the photo below.


Step 5:

Slide your wire thru the metal threaded cap from the USB adapter. THEN solder the Red wire to the metal plates and the black wire to the negative pin contact on the USB PCB.


Step 6:

Smosh your wires around so that the main run will fit out the bottom hole.


Step 7:

Snap the plastic clamshells back together, screw the metal cap back on, pop the metal top cap back on and replace the 2 screws. Smooth down your sticker if you still have it. If not, bust out that label maker and mark up which USB port is 1A and which is 2.1A. Don’t forget to set your font size to extra small.


And here it is installed in my bag. Now I am able to power my Signtek FM Transmitter and my iPad for F-Control.


Optional Step 8:

The two side cavities are open. You can fill these gaps with black hot glue. This will prevent dust and moisture from getting to the circuit.  You can also add 1″ male velcro around the sides to help it stick to the side walls of your audio bag.



Overall this is a fairly easy build.  Alternatively instead of wiring up a 2.5mm DC pig tail you could just use simple 2 wire power cable and a 4 Pin XLR. You would wire up the negative connection on the USB adapter to Pins 1 & 2 and the positive connection to Pins 3 & 4. A lot of IDX battery chargers feature 4 pin XLR ports, as well as PSC’s cart power options.

In a few days I’ll also be posting about how to add a backlit LCD battery meter to any BDS.

About the Author

Andrew Jones is a location sound mixer based in Los Angeles. He started in the TV and Film industry in 2004. You can email him at  Andrew@HoldForSound.com



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