DIY: Passive Direct Box
A DI box allows you to connect an electric instrument to a microphone input on a mixer. DI can stand for direct input, direct injection or direct interface. A DI box cuts out hum, noise, and distortion. This project is a passive DI. A passive DI is less flexible but requires no power or batteries, so it is more convenient. However, the performance is not as good. The quality of the DI depends on the quality of the parts. Components, especially transformers, vary widely in price, with more pricey components being of higher quality, but this project can fit every budget.
- Drill
- Plastic or metal project enclosure
- 2 phone jacks
- Balanced XLR jack
- Toggle switch
- Tape measure
- Wire cutters
- Roll of No. 22 wire
- Soldering iron
- Solder
- Needlenose pliers
- Balancing transformer
- Screwdriver
- Screws
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Instructions
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1
Drill holes in the enclosure to fit the 1/4-inch and XLR jacks and the toggle switch.
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2
Mount the jacks and switch in the holes.
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3
Cut nine lengths of wire. The wires will connect components, so their lengths depends on the dimensions of the project. Measure the distance between components to determine wire lengths, and cut the wire to these measurements.
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4
Strip off 1/4 inch from both ends of each wire with the wire cutter.
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5
Make connections between parts according to the first schematic in the Sound On Sound article listed in the Reference section.
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6
Solder the wires onto the terminals of the jacks and the switch.
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7
Attach the wires to the transformer screw terminals, and screw the terminals in place.
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8
Place the lid on the DI box, and screw it in place.