Radial Engineering USB-Pro User's Guide

®

True to the Music

USB-PRO

USB Direct Box

™

User Guide

Radial Engineering Ltd.
1588 Kebet Way, Port Coquitlam BC V3C 5M5

tel: [phone] • fax: [phone]

www.radialeng.com

[e-mail] • www.radialeng.com

®

™

Radial USB-PRO

USB to Audio Direct Box

Table of Contents Page

Overview .........................................................................1

Features ...........................................................................2

Getting started and audio connections ............................3

Testing and Using ............................................................4

Eliminating hum and buzz ................................................4

Using the headphone output ............................................5

Specications ..................................................................5

Radial Limited Warranty ...................................Back Cover

INTRODUCTION

Congratulations on your purchase of the Radial USB-Pro!
The Radial USB-Pro is a high-resolution stereo direct box
designed to convert sound les from a laptop computer
and seamlessly transfer them to a pair of balanced audio
outputs to feed a PA, recording or broadcast mixing
console.

Plug and play easy to use, the USB-Pro can be up and
running in no time. That said, as with any new product, we
recommend that you take a little time to read through the
manual in order to familiarize yourself with the USB-Pro
features so you can get the most out of it.

If you have any questions that are not covered in this
manual, please consult the FAQ section on the web site
as this is where we post the latest updates and questions
from other users. If you still can’t nd what you are looking
for, feel free to send us a note at [e-mail] and
we will do our very best to reply in short order.

®

True to the Music

OVERVIEW

The Radial USB-Pro is a plug and play, 24bit digital to analog audio

converter and professional direct box in a compact and road rugged
package.

A typical direct box is a device that lets you interface a high impedance
(hi-Z) audio output with professional low impedance (low-Z) PA and
recording systems. In the case of the USB-Pro, the digital audio signal
is controverted to analog and feeds directly into the direct box circuit
to produce low-Z balanced left and right stereo signals. The built in
preamp allows you to adjust the output level from mic-level to line-level
and enables the USB-Pro to connect directly to mixing consoles, power
ampliers and self-powered speakers alike. The USB-Pro ensures the
digital signal is delivered to the PA as faithfully as possible.

LEFT

DIGITAL USB

INPUT

CHANNEL

RIGHT

CHANNEL

MAC or PC

PA SYSTEMUSB-Pro

The USB-Pro is very easy to setup and use because it derives power
from the USB connection and automatically congures the sampling rate
and bit depth without the need for special drivers. The USB-Pro can be
used for audio playback, system testing and for transferring digital audio
les to analog for processing.

Following the block diagram below, a computer’s USB digital audio output
is converted to analog audio. A level control allows you to adjust the output
level and a mono sum switch can be activated to send mono signals to
two separate audio systems or check for phase issues. The 3.5mm mini­headphone output can be used to monitor the stereo signal. Before the
XLR output, isolation transformers may be switched into the circuit to
eliminate noise caused by ground loops. The signal is then balanced to
drive long cables without inducing noise.

RADIAL USB-Pro

DIGITAL TO

USB

ANALOG

INPUT

LAPTOP

Radial Engineering Ltd.

LEVEL

CONTROL

MIC TO LINE

1

STEREO /

MONO SUM

HEADPHONE

AMP

TRANSFORMER

ISOLATION

HEADPHONE

3.5MM OUT

BALANCED

XLR OUT

USB-Pro™