Radial Engineering ProD8 User's Guide

True to the Music

ProD8 Rackmount DI

Owner’s Manual

Radial Engineering Ltd.
1638 Kebet Way, Port Coquitlam BC V3C 5W9
tel: [phone] • fax: [phone]
email: [e-mail] web: www.radialeng.com

www.radialeng.com

Radial ProD8 Owner's Manual V1.0 - Part #: R870 1190 00
Subject to change without notice

Radial ProD8 Owner’s Manual

TABLE OF CONTENTS PAGE

Introduction .................................................................... Inside Cover

ProD8 Overview ............................................................................... 1

Feature Functions ............................................................................ 2

Rackmounting .................................................................................. 3

Using the ProD8 ............................................................................... 4

Adding Effects .................................................................................. 5

Typical Stage Set-up ........................................................................ 6

Redundant Inputs for Backup Instruments ....................................... 7

Redundant Inputs for Backup Playback ........................................... 8

FAQ .................................................................................................. 9

Warranty Information .........................................................Back Cover

Congratulations on your purchase of the Radial ProD8.

The Radial ProD8 is a simple yet remarkably clever direct box in that it provides all of the standard features
one would find in a typical rackmount DI plus several refinements: First off, it jams eight (8) direct boxes into
a single rack space making it the highest density DI on the market. Secondly, it is equipped with redundant
inputs on each channel that are pre-merged mono to reduce mixer and snake channel requirements or can
be used as redundant inputs for system backup. Thirdly, an effects-loop on each channel lets you share
your effect with two devices saving money and space. And finally, reversible rack rails let you position the
inputs and the outputs on the front or back of the rack to best accommodate your live or studio set-up.

As with all Radial products, we highly recommend that you read this short manual before using the ProD8
so that you become familiar with all of the features and functions to get the most out of this device. Should
you have any questions, please visit the FAQ section on our Radial web site as this is where we post the
latest applications. You can also email us at [e-mail] should you have a question that is not
answered.

We are confident that you will enjoy years of trouble free performance with your new Radial ProD8 and we
look forward to hearing back from you about new an innovative ways you have found to use it. Now start
reading and plugging away!

Radial Engineering
1638 Kebet Way, Port Coquitlam BC V3C 5W9
tel: [phone] • fax: [phone]
email: [e-mail] web: www.radialeng.com

Specifications and appearance subject to change without notice.

OVERVIEW

The Radial ProD8 is an 8 channel passive direct box
and does not require any powering whatsoever to make
it work. The high performance Radial transformers are
extremely efficient and will both balance the signal and
convert the high source impedance of your keyboards to
a balanced, mic level low impedance output.

All channels are identical and completely isolated. Each
channel features two inputs that are merged to mono
using a resistive mixer. This means you can use either
input for a mono source. If you have a stereo source
such as a synthesizer or digital piano, connecting the
instrument to the two inputs will yield a mono mix at the
XLR output. Should you wish to connect a high output
device like a CD player to the ProD8, a -15dB PAD will
reduce the input level going to the transformer to avoid
saturation. The ¼” THRU is a direct feed that would be
used for your personal monitoring system.

True to the Music

To further advantage the user, an effects-loop has been provided that allows the two inputs on each chan­nel to share the same effects processor. Each channel features an internal switch that lets you assign the
THRU output either pre or post the effects-loop depending on how you intend to use the system.

BLOCK DIAGRAM

IN-A

IN-B

*One of eight channels.

PASSIVE

SUMMING

SECTION

THRU
PRE/POST
EFX LOOP

EFFECT

LOOP

-15dB
PAD

THRU

OUT

POLARITY
REVERSE

XLR
OUT

GROUND

LIFT

CHASSIS
GROUND

LIFT

As previously mentioned, the ‘engine’ inside the ProD8 is the Radial transformer. This ‘hi-Z to lo-Z’ device
is designed to convert the impedance and balance the signal so that it matches the level of a typical micro­phone. This way, the keyboards connected to the ProD8 can be ‘managed’ just like microphones and used
with mic splitters as well as the mic inputs on the mixing console. A polarity reverse switch toggles pins 2
and 3 to allow older pre-AES standard gear to be connected in phase.

Transformers are particularly advantageous with keyboards and other devices that are electrically powered
through the common AC electrical system as they isolate the input from the output to help eliminate hum
and buzz caused by ground loops. A ground-lift switch further helps reduce noise by disconnecting pin-1 on
the XLR thus allowing the system tech to derive the channel ground from either the input or the output.

Radial Engineering Ltd. ProD8 Owner’s Manual

1

¼" PHONE PANEL

REVERSABLE RACK EARS

1

allow you to setup the ProD8
with either the ¼" jacks or XLR
connectors facing front.

IN-A/B dual inputs on each

2

channel auto-merge to mono.

3

THRU parallel thru-put connects
to on-stage amp or mixer for
personal monitoring.

4

LOOP each channel features
an effects-loop on a TRS jack.
Works like an insert on a mixing
console.

5

-15dB PAD reduces the input
level by -15dB to prevent
overload from high output
devices.

XLR PANEL

XLR OUTPUTS are balanced

6

600 ohm, mic-level and 100%
transformer-isolated to prevent
ground loops.

7

LIFT disconnects pin-1 on the
XLR output to isolate ground via
the transformer.

8

180° reverses pins 2 & 3 on the
XLR inverting the signal polarity
to correct out-of-phase signals.

True to the Music

1

6

2

7

3

4

8

5

INTERNAL

9

WELDED 14-GUAGE STEEL

9

10

11

12

13

rackmount enclosure is finished
in durable baked enamel.

10

RADIAL TRANSFORMER

with linear frequency response
from 20Hz to 18KHz for natural
sound. Mu-metal shield blocks
electromagnetic interference.

11

PRE/POST EFX internal switch
allows the THRU output to be
pre or post the effects-loop.

Factory set to post effects-loop.

12

CHASSIS GROUND internal
switch allows individual ground
paths for each channel.

Factory set in the lifted position.

13

MIILITARY-GRADE double­sided PCB is bolted to steel
standoffs for toughness.

14

ISOLATED CONNECTORS
extremely tough glass-filled
nylon for true channel isolation
from chassis ground.

Radial Engineering Ltd. ProD8 Owner’s Manual

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