Audient ASP 008 User manual

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©audient 05/2008
Copyright 2003. All rights reserved.
The information in this document is subject to change without notice.
Audient plc makes no warranty of any kind with respect to the material in this document
and shall not be liable for errors contained herein or for incidental or consequential
damages related to the use of the material.
No part of this document may be reproduced without the prior written consent
of audient plc.

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Contents
IMPORTANT SAFETY INSTRUCTIONS ............................................................5
UNPACKING ..................................................................................................6
MAINS POWER SUPPLY................................................................................. 6
VOLTAGES .....................................................................................................6
FUSES ...........................................................................................................6
MECHANICAL INSTALLATION ........................................................................6
ANALOGUE INTERFACES ............................................................................ 6/7
PIN CONVENTIONS .......................................................................................6
DIGITAL INTERFACES ................................................................................. 8/9
FUNCTIONS AND CONTROLS ........................................................................9
SAMPLE RATE ............................................................................................. 10
FORMAT..................................................................................................... 10
LOCK ........................................................................................................... 10
VARIABLE IMPEDANCE: WHAT IS IT AND WHAT DOES IT DO? .................... 11
SPECIFICATIONS ......................................................................................... 12
WARRANTY ................................................................................................. 12

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©audient 05/2008
Operation Manual
Introduction
Thank you for buying this Audient product.
The ASP008 features eight ultra high quality microphone preamplifiers using an 8
transistor discrete Class A front end with extended bandwidth and a noise floor close
to the theoretical Johnson limit. Carefully chosen close tolerance components are used
to achieve high CMRR at all gain settings and distortion is minimised to less than
0.001% at 20dB gain and +10dBu output.
This outstanding technical performance delivers a mic amp with incredible transparency
and detail without colouration or other unwanted artefacts.
Each Mic amp also features switchable input impedance, allowing the user to explore
the subtle variations in microphone character that are determined by output termination.
All channels include an XLR input, ‘soft start’ 48V phantom power, switchable input
impedance, 25-250Hz hi-pass filter as well as line input selection. Channels 1 and 2
also feature a 20dB attenuator and a high-impedance Instrument/DI input on a front
panel mounted jack. LEDs provide indication of signal present and overload. Digital
output options are available in addition to the standard balanced analogue outputs,
making the ASP008 an ideal “front-end” for any DAW or ProTools system .
We have designed this equipment to provide you with the best possible tool to deal
with today’s demanding requirements. We have taken a great deal of pride and care
in the manufacture of this equipment so that it will provide consistent and reliable
performance. Please take a little time to study the contents of this manual so that you
can be sure of getting the best performance from this equipment.

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Operation Manual
Introduction
EARTH This unit is connected via its power cord to the mains safety
earth. NEVER OPERATE THE UNIT WITH THIS EARTH
CONNECTION REMOVED.
COVERS DO NOT remove the covers. Refer servicing to qualified personnel
only.
VOLTAGE ASP008s are set to operate only at the voltage indicated on the
rear panel.CHECK that the correct voltage is available before
connecting the AC mains supply.
FUSES CHECK that the fuse fitted is the correct type for the local mains
voltage. ALWAYS replace fuse with the correct type.
MOISTURE DO NOT expose the unit to rain or moisture. If the ASP008
should become so exposed REMOVE the mains power immediately.
CABLES PROTECT the mains power cord from damage though impact or
abrasion.
HEAT ALWAYS site the ASP008 away from sources of heat including
direct sunlight and ensure adequate ventilation around the unit.
IMPORTANT SAFETY INSTRUCTIONS
RISK OF
ELECTRIC SHOCK
DO NOT OPEN
RISQUE DE CHOC
NE PAS ENLEVER
CAUTION ATTENTION
WARNING
THIS EQUIPMENT MUST BE EARTHED
DO NOT EXPOSE TO RAIN OR MOISTURE
Please read all of the following instructions and save them
for later reference before attempting to connect the
ASP008 to the AC power source.

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Operation Manual
Installation
Unpacking
Mains power supply
Voltages
Fuses
Your ASP008 has been carefully and meticulously tested and inspected before despatch.
Please check for any signs of transit damage. If any signs of mishandling are found
please notify the carrier and your dealer immediately.
Your ASP008 Series Mic Pre packing should contain an ASP008 rack unit, and a mains
power cable, along with this manual.
The ASP008 will be set and marked for either 230V or 115v operation. 230V models
will operate without performance degradation from 210V to 250V. 115V models will
accept from 105V to 125V. Do not attempt to operate the unit outside the relevant
range defined above.
For 100V operation please contact your dealer.
Mechanical Installation
The ASP008 rack unit is cooled using a very low noise fan. Care should be taken not to
obstruct the unit’s ventilation holes. Adequate air flow must be provided within rack
cases to prevent the unit from overheating.
Please note that the fuse rating for all voltage settings is 20mm T500mA. Always
replace fuses with the same type. The mains fuse is very unlikely to fail under
normal use and caution should be excercised if a failure should occur. Check for the
correct mains voltage, condition of the mains cord and integrity of the mains supply
before replacing the fuse.
MICROPHONE INPUTS MICROPHONE INPUTS
5 16 27 38 4
LINE OUTPUTS
LINE INPUTS
The ASP008 has been designed and developed to provide highly robust system
integration interfaces, allowing worry-free system hook-up under the most demanding
situations. Inputs and outputs are implemented using advanced electronically balanced
topologies and are fitted with extensive RFI rejection networks.
Pin conventions
To unbalance the outputs of the ASP008 the -ve Pin should be connected to its adjacent
0v pin at the output of the ASP008. Similarly, inputs from unbalanced sources should
be connected via twin screened cables with the -ve Pin connection tied to the screen at
the unbalanced source.
Line level inputs and outputs are provided on 25 pin D Sub female type connectors
with 4-40 screw thread jack posts. Wiring is in accordance with the TascamTM DA88
convention. Pin allocations are shown in detail on the next page. Additionally, Channels
1 and 2 have front panel mounted unbalanced high impedance jack inputs to allow
instruments to be directly connected to the ASP008.
Electronically balanced microphone inputs are provided on 3pin XLR female connectors
with Pin 2 Hot and Pin 3 Cold. Pin 1 is permanently connected to the ASP008 chassis
and thereby to the safety earth.
Analogue Interfaces

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Operation Manual
Installation
CHANNEL
NUMBER
+VE
SIGNAL
-VE
SIGNAL SCREEN
D-SUB PIN
124 12 25
210 23 11
321 922
4 7 20 8
518 619
6 4 17 5
715 316
8 1 14 2
Note: All undesignated pins are
unconnected. All screen connections are
joined inside the unit and connected to
metalwork earth.
+
+
++
PIN 1
PIN 13
1
2 4
6
3
7
5
8
WIRING SIDE OF FREE MALE CONNECTOR
Important : When preparing your D-SUB
interface cables please note that the
maximum shell size that can be
accommodated is 18 x 60mm.
In order to maintain optimum EMC performance it is important that screens are properly
connected at both ends of cable runs. In this way the electromagnetic shield provided
by the equipment chassis and the cable screens will be optimised to reject interference.
It is recommended that only high quality braided screen cables are used to avoid
compromising EMC performance.
Analogue Interfaces (cont)

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Operation Manual
Installation
Two optional digital interface cards are available for ASP008, either one can be factory
or retrofitted to all units. A cover plate is fitted to the rear of the chassis when neither of
the options is installed.
ADATTM SMUX
Digital Interfaces
A 9-Pin female D-sub type connector is
used to provide the required 8 digital
outputs (in 4 pairs - pair 1 carries channels
1/2 etc) at 44.1/48/88.2/96kHz (selectable
on the front panel) or external sample
rates. Separate fan-out cables are available
with XLR terminations for AES and RCA-
phono connections for SPDIF.
AES format is selected when the
associated switch is in its normal
(released) state. Depressing this switch
will set the outputs to SPDIF format.
The AES output is always 24 bit and is
not effected by the front panel format
control.
This card provides ADATTM digital outputs
at 44.1/48/88.2 or 96kHz (selectable on
the front panel) or at external sample rates
for all 8 channels on single (44.1/48kHz)
or dual (88.2/96kHz) ‘light pipe‘
connectors. The outputs can be set to 16/
20 or 24 bit depth using the front panel
controls.
At 88.2 and 96kHz sample rates, channels
1-4 use the upper ‘light-pipe’ connector
with channels 5-8 on the lower connector.
Channels 1-8 are output on both
connectors at 44.1 and 48kHz sample
rates.
AES/SPDIF ( with ADATTM SMUX)
ADAT 1-4
AES INT WORD
CLOCK
ADAT 5-8
CHANNEL
NUMBERS
SIGNAL
HOT
(Phono
centre pin/
XLR PIN 2)
SIGNAL
COLD
(Phono
sleeve/
XLR PIN 3)
SCREEN
(XLR PIN 1)
D-SUB PIN
1+2 9 5 1 -SHELL
3+4 8 4 1 -SHELL
5+6 7 3 1 -SHELL
7+8 6 2 1 -SHELL
Word Clock
A BNC along with an INT/EXT function
select switch is provided on both digital
output cards. With the switch released the
ASP008 will run off its internal clock
generator. Depressing the switch allows
a master word clock to be connected via
the BNC enabling the ASP008 converters
to be sync’d to an external source. The
front panel mounted LOCK led will
illuminate when the unit is locked, or flash
if word clock is not present or not
synchronised.
If external word clock is selected the
sample rate switch on the front panel will
no longer be operative.
The second card option provides AES/
SPDIF interfaces in addition to the ADAT
ports mentioned above.
ADAT 1-4
AES WORD
CLOCK
ADAT 5-8
ADAT 1-4
AES INT WORD
CLOCK
ADAT 5-8
ASP008 units support SMUX operation
from Serial number 180721. Earlier units
have provision for only the upper light-
pipe connector. The daughter board
carrying the lower connector on the digital
interface card must be unplugged for this
configuation, which provides connectivity
for channels 1-8 at 44.1 and 48kHz but
only for channels 1-4 at 88.2 and 96kHz.
The clock input on ASP008 is factory set
to be terminated. If the unit is to be used
in a wordclock chain the clock input
should be re-set to HiZ (unterminated).
To do this, set jumper JP1 (near the
output connectors on the digital card) to
the HiZ position.

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Operation Manual
Functions & Controls
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48V applies phantom
power to the
microphone input of
this channel. It is not
good practice to
switch phantom on
while monitoring a
channel, however a
proprietary ‘soft start’
feature is incorporated
to minimise the
potentially damaging
transients if phantom
is switched ‘live’.
INST (channels 1 and 2
only). This is a high
impedance 1/4” jack
input that allows the
direct connection of a
guitar without the need
for an external DI box.
-20dB (channels 1 and 2
only). Inserts a 20dB
pad on the microphone
input to enable very
high output sources to
be connected without
risk of overload.
With the PAD inserted
the available gain is
between -20dB and
40dB.
LINE connects the
electronically balanced
D-Sub input to the
channel. Gain range is
-20dB to +40dB. Note
that this input
selection overrides the
INST input.
I/PZ adjusts the
impedance of the
microphone input
Three settings are
provided 200,1200
and 5000 ohms.
GAIN 0 to 60dB of gain is
available (-20dB to
40dB with PAD or
LINE selected).
inverts the phase of the
input signal. This can
be particularly useful
when using multiple
microphone
techniques.
Switches in the 12dB
per octave high-pass
filter adjustable using
the rotary control from
25Hz to 250Hz.
SIG illuminates to show
that a signal at a level
above -25dBu is
present on this input.
PK lights when a signal
level above +16dBu is
detected.
Functions and Controls

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Operation Manual
Functions & Controls
Sample rate
Sample rates of 44.1/44/
88.2 and 96kHz are
supported. The desired
rate can be selected by
repeatedly pressing the
Sample Rate select switch
to step through the
available settings as
indicated by the 4 yellow
LEDs and the green LOCK
led. The chosen selection
is retained in memory and
restored after power
down.
The sample rate select
switch is not operable if
external word clock is in
use.
Format
ASP008 ADAT outputs
can be set to 16/20 or 24
bit formats by repeatedly
pressing the Format select
switch. The selected bit
format is displayed on 3
yellow LEDs and is
retained in memory and
restored after power
down. The AES outputs
are always 24 bit.
Lock
This green LED illuminates
when the ASP008 external
clock input has been
selected and the
converters have
successfully sync’d to the
external clock source. It
will flash if
synchronisation has not
been achieved.
Functions and Controls (cont)

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Operation Manual
Variable Impedance
Variable Impedance: What is it and what does it do?
Traditionally, in order to get the maximum signal transfer between microphone and
pre-amp, the recommended practice has been to ensure that the input impedance of
the pre-amp is at least 5 times the source impedance of the microphone. In other words,
a typical 200 Ohm microphone needs a 1kOhm input impedance. The mic is essentially
working without any load and is able to generate its maximum output voltage,
optimising the signal to noise ratio and usually providing the flattest frequency response
(or at least the frequency response the manufacturer intended). However, subtle
changes in tonal quality and microphone performance can be invoked by deliberately
making the microphone work harder by loading it with a different impedance.
The timbral changes caused by this can range from inaudible to quite dramatic, involving
a complex and interactive range of effects including level, frequency response, and
transient response.
The results will generally be most noticable on older ribbon and dynamic microphones,
which are transformer coupled. The loading on the transformer usually causes frequency
response and level changes, sometimes ironing out resonances. At the same time, the
increased damping of the magnetic circuit in which the ribbon or moving coil vibrates
causes changes to transient response. This is similar to the well known effect that
different amps can have on electric guitars, where the sustain is affected. Basically, the
loading on the guitar pickup "stiffens" the magnetic field in which the string is vibrating,
opposing the movement of the string.
Capacitor microphones tend to be less affected, especially modern transformerless types
that have a lower source impedance. The electronics in these microphones isolates the
effect of the loading from the capsule. Older transformer coupled types tend to be
better candidates for tonal manipulation, as they have a more complex source
impedance.
It is difficult to predict what the effect will be on any given microphone. Generally, a
higher input impedance (less loading) will give a more transparent, wide range sound,
while a lower input impedance (more loading) will increase warmth and reduce level.
The ASP008 provides a choice of three impedances, 200 Ohm, 1.2kOhm, and 5kOhm.
Don't be afraid to experiment. This is a technique that can easily extend the use and
application of your microphone collection. Remember, it's the sound that's important,
not the theory!

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Operation Manual
Specifications and Warranty
Specifications
Maximum I/P level +21.5dBu
Maximum O/P level +27.5dBu
THD Typically better than 0.007% at 1kHz any gain setting
EIN Better than -127.5dB @ 60dB gain/ref 150 ohms
Frequency Response -0.3dB @10Hz to -3dB @300kHz at unity gain
CMRR Better than 75dB at 1kHz and 60dB gain
Dimensions 480mm x 278mm x 44mm
Weight 4.5Kg
Power consumption 40 watts
In keeping with our policy of continuous improvement Audient plc reserves the right to alter
specifications without prior notice. E & OE
Warranty
Your ASP008 comes with a manufacturer’s warranty for one year from the date of
despatch to the end user.
The warranty covers faults due to defective materials used in manufacture and faulty
workmanship only.
During this warranty period Audient will repair or at its discretion replace the faulty
unit provided it is returned carriage paid to an authorised Audient service centre. We
will not provide warranty repair if in our opinion the fault has resulted from unauthorised
modification, misuse, negligence, act of God or accident.
We accept a liability to repair or replace your ASP008 as described above. We do not
accept any additional liability. This warranty does not affect any legal rights you may
have against the person who supplied this product – it is additional to those rights.
Audient plc, 1 Stable Court, Herriard Park, Herriard, Hampshire, RG25 2PL