PRESONUS DIGIMAX User manual

DIGIMAX
Eight Channel Microphone Preamplifier with Dual
Domain Limiters and Digital Outputs
User’s Manual
PreSonus Corporation

DigiMax
EIGHT CHANNEL MICROPHONE
PREAMPLIFIER
With
Dual Domain Limiters and Digital Outputs
USERS MANUAL
Version 1.0
2000, PreSonus Audio Electronics, Incorporated.
All rights reserved.

WARRANTY
PreSonus Limited Warranty
PreSonus Audio Electronics Inc. warrants this product to be free of defects in material
and workmanship for a period of one year from the date of original retail purchase.
This warranty is enforceable only by the original retail purchaser. To be protected by
this warranty, the purchaser must complete and return the enclosed warranty card
within 14 days of purchase. During the warranty period PreSonus shall, at its sole
and absolute option, either repair or replace, free of charge, any product that proves
to be defective on inspection by PreSonus or its authorized service representative.
To obtain warranty service, the purchaser must first call or write PreSonus at the
address and telephone number printed below to obtain a Return Authorization
Number and instructions of where to return the unit for service. All inquiries must be
accompanied by a description of the problem. All authorized returns must be sent to
the PreSonus repair facility postage prepaid, insured and properly packaged.
PreSonus reserves the right to update any unit returned for repair. PreSonus
reserves the right to change or improve the design of the product at any time without
prior notice. This warranty does not cover claims for damage due to abuse, neglect,
alteration or attempted repair by unauthorized personnel, and is limited to failures
arising during normal use that are due to defects in material or workmanship in the
product. Any implied warranties, including implied warranties of merchantability and
fitness for a particular purpose, are limited in duration to the length of this limited
warranty. Some states do not allow limitations on how long an implied warranty lasts,
so the above limitation may not apply to you. In no event will PreSonus be liable for
incidental, consequential or other damages resulting from the breach of any express
or implied warranty, including, among other things, damage to property, damage
based on inconvenience or on loss of use of the product, and, to the extent permitted
by law, damages for personal injury. Some states do not allow the exclusion of
limitation of incidental or consequential damages, so the above limitation or exclusion
may not apply to you. This warranty gives you specific legal rights, and you may also
have other rights, which vary form state to state. This warranty only applies to
products sold and used in the United States of America. For warranty information in
all other countries please refer to your local distributor.
PreSonus Audio Electronics, Inc.
7257 Florida Blvd.
Baton Rouge, LA 70806
[phone]
2000, PreSonus Audio Electronics, Incorporated. All rights reserved.

TABLE OF CONTENTS
3
1Overview
Introduction 5
Features 6
2 Controls & Connections
Front Panel Basic Layout 9
Back Panel Basic Layout 12
Power Supply 14
3Operation
Dynamic Microphones 15
Phantom Powered Microphones 15
Instrument Input 15
Enhancement 15
4Technical
Specifications 17

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1OVERVIEW
5
1.1 INTRODUCTION
Thank you for purchasing the PreSonus DigiMaxEight Channel
Microphone / Instrument Preamplifier with Dual Domain Limiters and
Digital Outputs. This digital pre-amp has been designed and constructed
using the very latest in components and technology to provide its user
crystalline audio reproduction for an infinite period of time. We at PreSonus
believe the DigiMax to be an exceptional sounding unit and an exceptional
value. Contact us at 1-800-750-0323 with your questions or comments you
may have concerning this unit or its operation. PreSonus Audio Electronics
is committed to the philosophy of constant product improvement. Our
experience has taught us the best way to convert this philosophy into action
is by listening to the experts on our gear, our valued customers. We
appreciate the support you have shown us through the purchase of this
product.
Please pay close attention when connecting your DigiMax to your system.
Improper grounding is one of the most common causes of noise problems
encountered in the recording or sound reinforcement environments. We
recommend scanning this manual before hooking up your DigiMax to your
system so you may familiarize yourself with its functions and features.
Good luck and enjoy your DigiMax!
1.2 FEATURES
The following is a summary of the features of the PreSonus
DigiMax
Dual Servo Mic Pre. Each channel of your DigiMax contains a
Class A discrete input buffer followed by a dual servo gain
stage. This provides ultra low noise and wide gain control
allowing the DigiMax user to boost desirable signal without
increasing unwanted background noise (NO capacitors!)

OVERVIEW
6
48V Phantom Power.Each channel of the DigiMax has 48V
Phantom power available. When the Phantom power switch is
engaged, power is supplied at a constant rate. This assures
optimum performance of your condenser microphone(s) and
that it will be free of distortion associated with insufficient power.
This switch is located on the back panel adjacent to the XLR
input.
Phase Reverse Switch. A phase reverse switch is provided on
channels One and Two. This switch enables the user to invert
the phase of a microphone when phase cancellation is noted.
The phase reverse switch allows the operator to avoid phase
cancellation when identical microphones are used in close
proximity to one another. The phase reverse switch also can
compensate for different XLR connector hook-ups where pin
connections have been inverted.
-20 dB Pad. A -20 dB pad is available on each channel of the
DigiMax for reducing in-coming signal levels to the unit. Using
this pad can provide a more manageable signal from high
output devices giving the operator greater control over the in-
coming signal and a much reduced chance of over-driving the
input and thereby avoiding distortion.
Enhance. The Digimax provides an EQ Enhancement feature
on each channel. Engaging this switch gives the processed
signal a cut of 3 dB between 250 Hz and 5kHz. This has a
smoothing effect on mid-range heavy signals and gives a flatter
response characteristic.
Sample Rate Selector. The Digimax has a switch on the front
panel that lets the operator choose the sample rate. It provides
selectable rates of 32k, 44.1k and 48k.
EXT CLOCK. When the External clock switch is engaged the
Digimax goes into “chase” mode and automatically recognizes

OVERVIEW
7
which of the three sampling rates is required for optimum
synchronization.
Dual Concentric Control. Each channel of the DigiMax has a
dual concentric rotary control for adjusting the channel’s gain
(inner) and for selecting the dual domain limiter’s threshold
(outer).
Analog Output. The rear panel of the DigiMax contains
analog impedance balanced outputs for each channel. These
outputs provide an analog duplicate of the digital output of the
unit. This duplication of the digital output allows the user to
monitor the analog output with a mixing console and
overcoming the “latency” problem (time delay) that may be
encountered when trying to record in “digital”.
Digital Optical Output. The DigiMax has a adatlightpipe
output that can be used with any commercially available digital
optical cable. This cable can supply eight simultaneous
outputs.
Digital Output. The DigiMax has a chassis mounted 9 pin
connector which can provide either AES/EBU or SP/DIF
outputs depending on which model of cable is used as well as
the internal configuration of the jumpers on the output card of
the unit.

2 CONTROLS & CONNECTIONS
8
2.1 FRONT PANEL BASIC LAYOUT
Notice that the front panel is divided into Eight Preamplifier sections,
Sample Rate Selector with Indicators and External Clock Switch.
Channel One and Channel Two each have a Hi-Z input (Channel Three through
Channel Eight do not have a Hi-Z input).
Both Channels One and Two contain:
•Phase Reverse Switch
•-20dB Pad
•Enhancement Switch
•Hi-Z Input
•Dual Concentric Control
(Inner-Gain / Outer-Limiter Threshold)
•-20/Clip/Limit LED’s
Channels Three through Eight contain:
•PAD

9
•ENH
•Dual Concentric Control
(Inner-Gain/Outer-Limiter Threshold)
•-20/Clip/Limit LED’s
Dual Concentric Control:
Gain. The inner concentric control provides 60dB of gain to the
processed signal. The amplifier has inherent gain of 12dB thus
delivering a total gain possibility of 72dB.
LIMITER THRESH. The outer concentric control sets the
Threshold of the dual domain limiter. The threshold ranges from 0
to +24dB.
-20 / Clip / Limit LED’s
The three LED’s found on each channel are provided to serve
different functions:
-20. The LED farthest to the left is labeled –20 and serves to
monitor whether or not signal is present at the channel output.
Clip. The LED labeled Clip activates at a pre limiter signal level of
+24 dB. Care should be taken to avoid using signal levels that
cause this LED to become active. Signal levels that reach or
exceed this amount of output will cause undesirable artifacts
(distortion) in the channel output signal that is being indicated by
this LED. The signal level is reduced by rotating the channel’s
inner concentric control, counter-clockwise.
LIMIT. The LED farthest to the right is labeled LIMIT. This LED is
activated by signal levels that reach or exceed the level that is pre-
determined by the Threshold setting selected (outer concentric
control). The setting of this control selects the point at which the

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limiter acts upon the signal coming through the channel.
Proprietary technology of the dual domain limiter allows it to act
instantaneously upon the signal at Threshold. The unique benefits
of peak limit control have been combined with the desirable audible
results of RMS limiting to provide DigiMax users with completely
transparent overload protection for digital recording. (NOTE: It is
possible to get some very cool effects by driving the limiter with
transients. These effects may be achieved by using low threshold
settings and high gain. Care must be taken to avoid distortion.)
§Sample Rate Selector
§LED Indicators -(32k 44.1k-48k)
§EXT Clock
The section at the extreme right of the front panel contains the Sample Rate
Selector Switch with LED indicators provided for 32k, 44.1k and 48k. This
section also contains a switch labeled EXT. CLOCK. When this switch is
engaged the operating clock rate of 32k, 44.1, or 48k will be determined by
the incoming signal from an external device through the Word Clock In input
on the back panel of the DigiMax.
2.2 BACK PANEL BASIC LAYOUT
Digital Optical Output. An adatoptical output (lightpipe) is
provided on the rear panel of the DigiMax. Eight simultaneous 24bit
outputs are possible when using the optical out.
Digital Output Connector. A female nine pin (DB9) connector on the rear
panel of the DigiMax provides 24bit digital output. This connector comes
configured from PreSonus for AES/EBU output (4 pair stereo) when used
with the (optional) Model No. 510- DMAX 007 cable available at an

11
authorized PreSonus dealer or which can be ordered directly from
PreSonus. S/PDIF outputs can also be obtained from an Authorized
PreSonus dealer by purchasing a Model No.510-DMAX008 cable or by
ordering the cable from PreSonus. The use of the S/PDIF output requires
re-configuring the jumpers on the output card of the DigiMax. While this is
a simple operation, care must be taken when moving the jumpers. A
diagram and complete instructions regarding this procedure are included
with the 510-DMAX008 cable. Should you need further assistance, contact
Customer Support at PreSonus by calling 800-750-0323 between the hours
of 10:00 AM and 5:00 PM CST
Word Clock Out/In. The Word clock output and input are accessed through
separate BNC connectors. The internal sample rate can be set to send 32k, 44.1k,
or48k. The Word Clock In scans the incoming information and automatically
synchs to the necessary sample rate.
+48V. A switch labeled +48V is located next to each microphone
input. This switch may be engaged to provide phantom power for
condensor mics and any other device, which may require phantom
power by way of the XLR input. This power is supplied at a constant rate to allow
use of all eight inputs, simultaneously, without any degradation of audio quality.
PIN 1 GND
PIN 2 +48v
PIN 3 +48v
XLR connector wiring for Phantom Power
ANALOG OUTPUT. Each channel of the DigiMax has an analog
output that parallels the digital signal being sent from the
associated channel. This output can be very useful for monitoring
purposes by helping in overcoming the time discrepancy that may
be encountered in some digital recording situations. This output is
impedance balanced and the connection is wired as follows:
TIP Signal 51ohms

12
RING 51ohms
SLEEVE GND
Analog Impedance Balanced wiring diagram
2.3 EXTERNAL POWER SUPPLY
The External Power Supply supplied with the DigiMax has two cords attached to
the unit. The cable labeled DC/OUT goes to the DC input on the DigiMax pre-amp.
The cord labeled AC goes to the electrical power source . The DigiMax is
configured at the factory to operate on specific voltages. Make sure the unit is set-
up for the correct voltage available in the locale where the unit is to be operated. If
you are unsure whether or not the unit you have is configured for the available
voltage in you area, contact an Authorized PreSonus dealer in your area before use
to avoid physical injury to the user or severe damage to the unit could result. The
four green LED’s on the face indicate the presence of current on the power rails.
V1=+5 volts, V2=16.5 volts, V3=-16.5 volts, and V4=+48 volts respectively.
WARNING! Before powering up your DigiMax for the first time make
certain that the stated power requirement of the unit (as stated on top
of the external power supply) matches the voltage supplied in the
country where the unit will be operated (USA = 115V). Failure to do
so could result in injury or even death to the user and the probability
of irreparable damage to the unit is highly likely.

3 OPERATION
13
3.1 DYNAMIC MICROPHONES
Dynamic microphones are characterized by lower output levels. Hence, more gain is needed to
amplify a dynamic microphone to operating level. Occasionally it is necessary to add the –20dB pad
to the microphone to avoid distortion (e.g. when recording percussion). Do not use phantom power
when using dynamic microphones.
3.2 PHANTOM POWERED MICROPHONES
Phantom powered microphones such as condensors and some ribbon microphones require external
power to pre-amplify the microphone acoustic pickup. These microphones typically have much
higher output than dynamic microphones. Hence the –20dB pad is almost always necessary when
close micing to avoid clipping the amplifier.
3.3 INSTRUMENT INPUT
The instrument inputs on channels one and two are designed to handle ¼” plugs from instruments
such as electric guitars and basses. These instrument inputs are ultra high impedance amplifiers
designed to allow the audio potential of an acoustic or electric instrument pickup to be fully realized.
Care should be taken not to overdrive these inputs with the signals from instruments with on-board
preamplifiers.
3.4 ENHANCEMENT
The Enhancement function of the DigiMax gives the processed signal a 3dB cut from 250
Hz to 5kHz. The slope of this frequency cut has a smoothing effect on the signal that is
being processed. For certain voices and microphones, which may tend to possess a
characteristic mid-range rise, this feature will have the effect of flattening the mids. This
will result in a fuller frequency response and an apparently richer; fuller sound.
Experimenting with the Enhancement feature will allow you to expand the sound potential of
your available microphones and instruments. The following graph is a representation of the
EQ curve derived with the ENH switch, engaged.

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4.1 TECHNICAL SPECIFICATIONS
DigiMax Technical Specifications:
Number of Channels Eight
Input
Input Impedance, XLR Input 1.3kΩ
Input Impedance, Instrument Input 1MegΩ
Connectors NeutrikXLR
1/4”TS Ch.1&2 only)

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Panel Controls
Gain 0dB to +40dB
Limiter 0dB to Off
Phase Reverse (1 & 2 only)
Pad -20 dB
Phantom Power +48 V (Back Panel)
Meters
Signal Present LED -20dBu
Clip LED +22dBu
Limit LED Limiter Active
Output
¼” TRS Impedance Balanced 51Ω
adatlightpipe digital optical 24bit
AES/EBU (4 pair stereo) 24bit
S/PDIF (4 pair stereo) 24bit
Digital
Sampling Rates 32kHz, 44.1kHz, 48kHz
Dither Type Psycho-acoustic
Performance
THD + Noise (Un-weighted) <0.009%
Noise Floor -94dBu
Signal to Noise >98dB
Analog Dynamic Range >120dB
Power Supply Rejection >98dB
Amplifier Type Dual Servo
Power Supply
Type Linear, External
Input 100/120/220/240VAC (Factory Configured)
Power 80 Watts

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Physical
Size 1U Rack
Dimensions 19” X 1.75” X 7”
Weight 15 lbs.
Chassis Steel
Panel Aluminum
As a commitment to constant improvement, PreSonus, Inc. reserves the right
to change any specification stated herein at any time in the future without
notification.