ARX DI-Plus User Manual

Specifications
Max Input Level +13 dB Phantom powered

+6 dB Battery powered

Input Impedance 1 Meg Ohm
Max Output Level

+17 dB 10K Ohm load Phantom powered
+12 dB 10K Ohm load Battery powered

+11 dB 600 Ohm load Phantom powered
+12 dB 600 Ohm load Battery powered

Output Impedance 680 Ohms Balanced
Signal to Noise –100 dB unweighted

–104 dB A weighted

Dynamic Range

117 dB 10K Ohm load Phantom powered
112 dB 10K Ohm load Battery powered
111 dB 600 Ohm load Phantom powered

107.5 dB 600 Ohm load Battery powered

Distortion 100 Hz .0027%

1KHz .0028%
10KHz .0037%

Frequency Response 20Hz to 20KHz, ± 0.2 dB
Gain through Unit 6dB (Normal input, P ad switch out)
Pad Switch –20 dB attenuation
Speaker Input

-40 dB attenuation, equivalent to 100:1 decrease in
input level; -60 dB atten. available with Pad switch

Input Connectors Insulated jack
Output Connector

3 pin XLR. Wired Pin 1 Ground, Pin 2 + Hot, Pin 3 –
Cold. With Audio Ground (Pin 1) lift switch

Construction All-steel chassis, fibreglass PCB
Battery Access Twist connector opens chassis, snap-in

battery holder inside. No tools required

Using the DI-PLUS

The DI-PLUS is a Direct Injection, or
Direct, box. It is a self contained,
stand alone unit designed to interface
unbalanced high impedance lines
with professional balanced low im­pedance inputs. In other words, it
will convert an ordinary signal into
one that is happy to travel down a
long line and meet a mixing console
at the other end. It has many appli­cations for Live Sound, Studio or
Broadcast use.

Typical uses are:

• Musical instruments - Bass guitar,
synthesizers, electronic drums, drum
machines

• Consumer audio products - cas­sette decks, tape decks, video cas­sette audio, computers, telephones.

Operating instructions

Normal Connection

Plug a jack lead with a high imped­ance source (instrument, unbalanced
line or similar) into the Normal In­put. This will turn the unit on and a
balanced signal will appear at the
XLR Balanced Output on the rear of
the unit. This connects to the Input
of the mixing console.If the signal
needs monitoring, eg. an onstage am-

plifier, then connect a lead from the
Loop Out to the amplifier . Pushing the
Pad switch IN will reduce the input
level by -20dB if required. Special
Note. The DI-PLUS is a Line level de­vice, so it is not designed to accept Mi­crophone level signals.

Connection from Amplifier

For applications where the sound of
the instrument/amplifier combination
is required, connect a lead from the
Aux (or External) speaker output on
the rear of the amplifier to the Speaker
Level Input (-40dB) on the DI-PLUS.
If the signal is still too hot, then switch
the Pad switch IN as well to reduce
the input by a further -20dB.
Note: Be sure to always use the Aux
or External speaker output on the
amplifier. Never disconnect the
speakers on a valve/tube amplifier .

Output Connections

Connect a balanced microphone lead
from the 3 pin XLR connector on the
rear of the DI PLUS to an input chan­nel of the mixing console. Pushing the
Audio Ground Lift switch IN will iso­late Pin 1to stop Ground Loops if re­quired.

Power Requirements

The DI-PLUS is an active device, ie.
it needs power to run. This power
can be supplied 2 ways:

• Battery power .

The DI-PLUS has provision for 1 x 9
volt battery internally . To get to the
battery compartment, unscrew the
knurled knurled captive bolt on the
rear panel, and push the top part of
the chassis upwards. The battery
compartment will immediately be
visible. Remove the old battery, re­place with a new 9v alkaline battery
and close the lid. Re-tighten the bolt
finger tight only .
That’s all there is to it. No tools, no
screwdrivers required!

2

3

1

• Phantom power .
The DI-PLUS will also run on Phan­tom power if available on the mix­ing console. Switch the Phantom
power ON on the channel the DI­PLUS is plugged into, and the Red
Phantom power LED will light up on
the DI-PLUS. This means the DI-

Page 4

PLUS is now running on the Phantom
power and the batteries are disen­gaged. If you switch the Phantom
power off the DI-PLUS will revert to
battery operation, although we rec­ommend using Phantom Power if
available as it gives an approx 6dB in­crease in overall headroom (see Speci-

fications, p 4).

Did you know...

ARX manufacture a complete range of
singles and multiple Direct boxes:
The DI-4 is a 19” 1 RU AC powered unit
which has 4 independent Direct boxes,
each with high impedance Input and
Loop out jack connectors, a oo to +15dB
level control, clip LED, balanced XLR
output and individual audio ground lift
switches. As well as Direct mode, it can
also function as a 4 into 2 stereo line
mixer, at the same time, with Pan con­trols, plus an Aux send and stereo Aux
return. For total flexibility channels 1 and
2 can also be switched out of the mix to
direct only .
The DI-6s is a 19” 1 RU AC powered
unit that has 6 independent Direct boxes,
each with high impedance Input and
Loop out jack connectors, a oo to +15dB
level control, clip LED, balanced XLR
output and individual audio ground lift
switches. It can also function as a 6 into 1
line mixer at the same time. A switch
on the rear changes it from a 6 into 1
mixer to a 1 into 6 line distribution
splitter, each split’s level controlled by
the six individual channel controls.
A true Pro Audio toolbox!

Page 5

INTERNATIONAL LIFETIME WARRANTY

ARX Systems (ARX) warrants to the first purchaser of this DI-PLUS
that it is free from defects in materials and workmanship under nor­mal use and service. ARX’s sole obligation under this warranty shall
be to provide, without charge, parts and labour necessary to remedy
defects, if any , which appear within twelve (12) months from date of
purchase; and to supply parts only for the life of the product to the
original purchaser .
This is our sole warranty. It does not cover finish or appearance items,
nor does it apply if the DI-PLUS has been, in ARX’s sole judgement:

• Subjected to misuse, abuse, negligence or accident;

• Repaired, worked on, or altered by persons not authorized by ARX,

• Connected, installed, adjusted or used otherwise than in accord­ance with the instructions supplied by ARX.

This warranty gives you and us specific legal rights, and you may also
have other rights which can vary from state to state.

To obtain warranty service for your DI-PLUS, call or write to
ARX or the dealer you purchased it from. They will give you
the correct address to send your unit to. Have your sales
receipt showing date of purchase handy, and include a copy
with your DI-PLUS. Pack the unit well - we are not responsi­ble for damage caused by unsuitable packing during ship­ment. Send the unit to us pre-paid, by a delivery service like
FedEx, UPS, or any other service that can track the ship­ment. We will return it to you freight paid.
If you have any questions, or any part of this is unclear , please
write to ARX Systems in the country of purchase, or to the
address below.
PO Box 15, Cheltenham, Victoria 3192, Australia.
Phone: [phone] Fax: [phone]
Y ou can also Email the factory at: [e-mail]

Page 7Page 6

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Owner's Manual

Active Direct Box

Single Channel

DI-PLUS

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DI-PLUS Manual v 1.1 ©1999 ARX®

Email: [e-mail]

International Fax: [phone]

Phone: 03 - 9555 7859 Fax: 03 - 9555 6747

Cheltenham, Victoria 3192, Australia

ARX Systems Pty Ltd, PO Box 15,

Thank you for choosing this ARX DI­PLUS, a major step forward in active
direct boxes. We hope you enjoy us­ing this unique product as much as we
enjoyed creating it. As with all ARX
equipment, it has undergone exten­sive factory testing and ‘burn in’ be­fore shipping. To ensure continued
trouble free use, please familiarise
yourself with the contents of this
manual before using.

Packaged in a single channel stand­alone format, the DI-PLUS represents
a fresh look at active D.I. concepts.

• Precision engineered

Ultra quiet, ultra clean circuitry de­livers maximum headroom whatever
the signal. Premium grade compo­nents, plus an all-steel chassis gives
excellent hum and noise specifications
and superb audio quality in a tough,
roadworthy package.

• Level control

The DI-PLUS features a Normal gain
high impedance unbalanced input on
the front panel, running to a balanced
XLR output on the rear . There is also
a separate -40dB Speaker Level input
for signal coming from the External
(auxiliary) speaker output of an am­plifier. A a global Pad switch drops
both the normal input and the speaker
input by a further 20dB, making it suit­able for all applications, from the soft­est keyboard to the hottest broadcast
levels.

• Battery compartment

The revolutionary simple ‘clamshell’
action of the DI-PLUS battery com­partment makes battery changing
ext-remely easy , even on the darkest
stages. A 9v alkaline battery snaps into
a PCB mounted battery holder for
fast, secure location. No fragile bat­tery clip leads to break, no tools re­quired, no screws to lose. Production
crew heaven!

• Automatic Phantom switching

The DI-PLUS will automatically switch
itself to the console’s own Phantom
Power, if available, and an LED will
indicate this mode. Turn the Phantom
Power off and it will instantly revert
back to battery mode.

• Rugged all-steel case

A lot of direct boxes are fitted into
brittle cast alloy cases. Not this one!
The tough all-steel inner and outer
chassis of the DI-PLUS provide excel­lent RF/EMF shielding while making
it a sturdy , heavy duty unit that is hard
to dislodge, and hard to leave behind.
Whether you’re a Studio or Live
Sound engineer , installation contrac­tor , or broadcast engineer , you want
all the dynamics and clarity of the
original sound source transferred to
the mixing console.

The ARX DI-PLUS provides a rugged,
no-compromise solution to all direct
injection and signal balancing require­ments.

Page 2

Front Panel Connections

• Speaker Level Input

• Normal Input

• Pad switch

• Loop out

• Battery check switch and
green battery status LED.

Rear Panel Connections

Balanced XLR output

connector . Pin 2 + Hot,
Pin 3 – Cold, Pin 1 Audio
Ground.

LED will light up when
switch is pressed if battery
is good

• Red Phantom power LED.
Will illuminate if DI-PLUS
detects Phantom power .

• Audio Ground lift switch.
Will isolate Pin 1 when
switched IN

Page 3