What is a DI Box?

DI stands for Direct Inject. A DI box is a device which changes a signal into a low impedance balanced signal suitable for driving long cable runs and suitable for Mic input sockets on mixing consoles.

A BSS Ar-133 DI Box (very common)

Who or what will use one?

Bass Guitars, Acoustic Guitars, Keyboards, Samplers, Computer Equipment amongst other things require a DI box to convert their unbalanced signals to a suitable one.

Some Bass Amps have a DI out on them, this however is after the preamp. Some engineers prefer a direct signal from the bass guitar to work with a flat signal. To help with this most DI boxes have a link socket which is a parallel link from the input which can then go to an amplifier.

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There are Passive and Active versions available, Active versions require power of some sort. This can be battery powered (usually 9v), Phantom power from a mixing console or sometimes mains powered. Often a DI box will accept more than one type of power.

Other Features

• DI Boxes sometimes have Attenuation switches on them to attenuate the signal at input. this is handy for particularly hot signals like DJ Equipment or keyboards.

• DI Boxes usually have a ground lift function which can reduce mains hum from a signal. It is usually common practise to solve the problem at source before using this option.

• DI Boxes powered with a battery will often automatically switch off with no input or output plugged in. However do not assume this to be so. If you must use a battery then be careful to switch off the DI box or remove the battery when not in use. See Tip of the Day below.

• There are rackmounted versions available with multiple channels. These are sometimes passive sometimes mains powered.

Tip of the Day

The common Behringer DI100 box has buttons which are prone to accidental activation. This can lead to a lot of stress in a live environment.

• For Attenuation buttons cut a piece of rubber or very thick card about 30mm by 25mm
• Cut out 2 rectangles the same size as the buttons.
• Try not to cut yourself as this can cause problems.
• Glue this material over the attenuation buttons with the buttons sticking through the 2 holes.

You now have recessed buttons which are difficult to operate accidentally.

• Repeat for other buttons as necessary.