Introduction - Radial Engineering PRO DI User Manual

True to the Music

INTRODUCTION

The Radial PRO DI is a passive direct box. This means that unlike active direct boxes that either require a battery or power
of some sort to make them work, your PRO DI does not need any power at all. It is 'plug & play' easy-to-use.
A direct box is primarily used to convert a high impedance instrument signals
to a low impedance balanced mic-level signal, which can then be
processed like a microphone and driven through long cables without
introducing noise. The PRO DI employs a high quality impedance-
matching transformer to do the conversion.
Typical applications for the PRO DI are connecting electronic
instruments like guitar, bass, keyboard, and drum machines
directly to a PA or recording system. Because the output of
the PRO DI matches that of a typical microphone, the PRO
DI is perfectly suited for use in live sound and recording stu-
dio systems where microphone signals are put through long
cable systems to a mixing console and where all signals are
balanced to keep noise down.
The cool thing about transformers is that they not only stop noise
caused by ground loops, they can be connected to work in both
directions! In other words, your PRO DI can convert a hi-Z unbalanced
input to a low-Z balanced microphone signal (typical use) or it can do it in
reverse and convert a low-Z balanced microphone signal to a hi-Z unbalanced
output. Connecting the PRO DI in reverse, you could for instance, take the balanced
output from a mixer and send it to a DVD recorder for proper impedance and level matching, or take a pre-recorded track
from a digital workstation and send it to a guitar effect pedal for re-amping effects. A good passive DI can be used to inter-
face all kinds of audio equipment and can solve many impedance and noise problems.
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Radial Engineering PRO DI User Guide