Aphex CHANNEL User manual

OWNER’S MANUAL
THE COMPLETE CHANNEL STRIP FOR VOICE AND INSTRUMENTS
CHANNEL™
MASTER PREAMP & INPUT PROCESSOR

Channel
Page 2
Safety Declarations
CAUTION: For protection against electric shock, do not remove the cover. No user serviceable parts inside.
WARNING: This equipment has been tested and found to comply with the limits for a Class A digital device pursuant to Part 15
of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment
is operated in a commercial environment. This equipment generates, uses, and can radiate radio frequency energy and, if not
installed and used in accordance with the operating guide, may cause interference to radio communications. Operation of this
equipment in a residential area is likely to cause interference in which case the user will be required to correct the interference
at his own expense.
The user is cautioned that changes and modifications made to the equipment without approval of the manufacturer could void
the user’s authority to operate this equipment.
It is suggested that the user use only shielded and grounded cables to ensure compliance with FCC Rules.

Page 3
Owner’s Manual
Copyright 2011 by Aphex. All rights reserved. All Aphex products are trademarks or registered trademarks of Aphex. Other brand and prod-
uct names are trademarks or registered trademarks of their respective holders.
1.0 CONTROLS & INDICATORS
2.0 INSTALLATION AND INTERFACING
2.1 Installation
2.2 Rear Panel View
2.3 AC Line Connection
2.4 Mic Input Connections
2.5 Insert Jacks
2.6 Output Connections
2.7 Digital Audio Outputs
2.8 Word Clock
2.8.1 INT/EXT
2.8.2 WC IN
2.8.3 WC OUT
2.8.4 Local Clock Mastering
2.9 Power Supply
2.10 Cough Switch
3.0 USING THE Channel
3.1 Using the Mic Input
3.2 Using the Instrument Input
3.3 Using Phantom Power
3.4 Using the Polarity Switch
3.5 Using the Pad
3.6 Using the Low Cut
3.7 Using the Phase Rotator
3.8 Using the Compressor
3.9 Using the Logic Assisted Gate
3.10 Using the De-esser
3.11 Using the Equalizer Block
3.11.1 Big Bottom
3.11.2 Parametric Equalizer
3.11.3 Aural Exciter
3.12 Using the Level Control
3.13 Clip Light
4.0 WARRANTY AND SERVICE
4.1 Limited Warranty
4.2 Service Information
5.0 SPECIFICATIONS
5.1 General Specifications
5.2 Architectural Specifications
5.3 Patent Notice
Table of Contents
4
6
6
6
6
6
7
7
7
7
7
7
7
7
7
8
8
8
8
9
9
9
9
9
10
10
10
10
10
10
10
11
11
12
13
14

Channel
Page 4
POWER INDICATION
The Aphex logo above the power switch glows yellow during the tube
preamp’s warmup time and green when the unit is ready.
LOW NOISE MIC PRE
The Channel works with all professional microphones. The clean and
stable 48V phantom supply is suitable for even the most expensive
microphones. The 12dB/octave low cut filter starts at 70Hz to effec-
tively reduce wind blast without diminishing voice body. Included is
a selectable phase rotator following the principles of the Spectral
Phase Refractor (SPR) circuit. The main bebefit of the Phase Rota-
tor is that by making certain voice waveforms more symetrical, the
compressors action becomes more efficient. This allows for a more
optimized output level.
COMPRESSOR
The Channel includes a special version of Aphex’s patented
Easyrider™ Compressor which has proven to be outstanding. It is
very simple to use with only two controls: Gain/Drive and Release. To
get deeper compression, turn up more Gain. To manage the density
and loudness, work with Release. Faster is louder and denser. Slower
is more natural and open. Note that turning up the Gain/Drive to
get more compression alters the overall gain structure through the
device such that the output may need compensating adjustment.
LOGIC ASSISTED GATE™
Once triggered, even by a microscopic transient, the signal pro-
gresses fully through the attack, hold, and release sequence. This
virtually eliminates the chatter experienced with other gate products.
The attenuation depth and gating threshold are user adjustable to
allow for varying requirements.
1.0 Controls and Indicators
DE-ESSER
Using a split-band technique with Linkwitz-Riley crossovers, the voice
remains bright and sharp, never losing presence while de-essing. The
de-ess threshold control lets you chose the essing level that you want.
EQUALIZATION BLOCK
A fully parametric equalizer band is provided along with the popular
Aphex Big Bottom and Aural Exciter. These features increase power,
punch and intelligibility without adding noise or an increase in
output level. As a real plus, they are also very easy to adjust.
REAR INSERT JACK
Allows you to insert any kind of line level audio equipment into the
signal path between the Channel’s dynamics processing and the
equalizer section. The operating level at this jack is 0dBu. You should
set up your inserted outboard gear accordingly.
METERS
Meters are provided for peak output level (relevant to both analog
and digital headroom at 0dB = max before clip) and the compres-
sor’s gain reduction. The output level bar graph will move upwards
indicating level, and the gain reduction bar graph will move down-
wards indicating gain reduction.
OUTPUT CONTROL
Once all processing and equalization is set where you want it, the
output level may need to be adjusted. Do not let the peak level fre-
quently exceed -6dBFS. This will make sure the digital output car-
ries well through subsequent mixing and processing. When using
the analog output, adjust the level to produce the desired average
output level (0VU) as seen on the outboard equipment’s meters.
GAIN/DRIVE
Adjusts
preamp gain
and drive into
the compres-
sor.
Lo Cut
Switches on
the 70Hz Low
Cut filter.
Invert Polarity
When
pressed,
inverts the
polarity
(phase) of the
mic input.
Phase Rotator
Enables the
Spectral Phase
Refractor
to improve
speech sym-
metry.
Compressor
Turns on the
Easyrider
compressor
circuit.
RELEASE
Controls the
density of
compres-
sion. Slow
for natural
leveling and
fast for more
loudness.
GATE THRESHOLD
When the sound is higher than this level,
the gate opens up instantly. No “chat-
tering” thanks to the patented Logic
Assisted Gate.
CLIP/MUTE
Flashes yellow when the
preamp is muted by the
cough switch. Flashes red
indicating clipping.
PAD
When pressed,
turns on the 20dB
input pad.
48V
When pressed,
turns on the micro-
phone phantom
48V power
IINSTRU-
MENT INPUT
Allows con-
nection of
a guitar or
bass.

Page 5
Owner’s Manual
Why You Shouldn’t Connect the Channel’s Output to a Mic Level Input.
The bottom line: you will get an unsatisfactory noise level. The Channel is designed to generate a line level
output from a mic level input. It optimizes the signal to noise ratio by giving you a strong signal far above the
preamplifier’s basic self noise level. This strong output signal can be up to 65dB higher than the mic signal.
It is perfect for a standard line input of a mixer or console but can overload a mic input. If you have no other
choice but to plug the Channel in to a mic input, turn that mic input’s gain all the way down. If the signal still
clips the input, try bringing down the Channel output level.
GATING
Shows when
the gate is
closed or clos-
ing. When the
light is off, the
gate is fully
open.
DEPTH
Lets you set how much attenuation the gate
will deliver. Use the lowest attenuation that’s
needed to reduce room wetness, breath,
or background noise. Usually 6 to 15dB is
sufficient. Fully CCW is off.
BIG-BOTTOM
FREQ
Adjusts the
frequency
below which
enhancement
takes place.
PARAMETRIC EQ
Works like a standard parametric band
with tune, Q, and boost/cut controls.
AURAL EXCITER
FREQ
Adjusts frequency
above which
enhancement
takes place.
AURAL EXCITER
AMOUNT
Adjusts the strength
(boost) of the Aural
Exciter effect.
BB/EQ/AX
ON
Switches
the BB/EQ/
AX on/off.
Provides full
true bypass
of the circuits
when off.
OUTPUT
Adjusts the
final pro-
cessed output
level as seen
on the VU
meter.
Line Level
Processor,
i.e.,
Compressor, EQ
+4dBu
Balanced
XLR Output
Rear Panel Analog Connections
BALANCED
TRS
Rear Panel Digital Connections
AES/EBU
OUTPUT
Digital 110
Ohm cables
only. (Do not
use regular
audio cables.)
S/PDIF &
OPTICAL
OUTPUTS
All outputs are
active at the
same time.
WORD CLOCK
BNC input and output jacks.
DIGITAL AUDIO
The Channel supplies industry
standard stereo AES/EBU, S/
PDIF, and TOSLINK digital audio
outputs. The single mic channel
appears on both stereo chan-
nels as a mono signal. Sample
rate and word clock options are
all available at the front panel.
The word clock selection LEDs
will flash when no clock signal
is present and light solid when
locked.
MIC INPUT
Works with all standard
microphones, phantom
powered or passive. Phan-
tom power activated from
front panel.
COUGH
SWITCH
Allows you to
silently mute the
output on the
fly using a hand-
held, desktop, or
floor switch.
BIG-BOTTOM
AMOUNT
Adjusts the
strength
(boost) of the
Big Bottom
effect.
DE-ESS
THRESHOLD
Lets you
set the level
where you
want your
esses to level
off.
DE-ESSING
Shows when
the the
de-esser is
working.
When the light
is on, sibilance
is being
controlled.

Channel
Page 6
PROPER MICROPHONE CABLE WIRING
Female XLR Male XLR
2.0 Installation & Interfacing
2.4 MIC INPUT CONNECTION
The microphone input connector is located on the rear
panel. It is the standard XLR-3F type. Use only properly
wired balanced mic cables.
CAUTION: Some ribbon mics will be damaged by
phantom power, some ribbon mics require phantom
power and some just ignore it. Please consult your
ribbon mic’s manual before connecting it to the Chan-
nel.
CAUTION: Beware that 48 volt PHANTOM POWER
may be applied to the microphone input, creating a
potential shock hazard. Shut off the phantom power
before plugging or unplugging microphones, waiting at
least 10 seconds for the voltage to fall. This also pro-
tects sensitive microphones against power inrush.
2.5 INSERT JACKS
The Channel allows you to insert additional signal pro-
cessing between the Channel’s dynamics processing
and the equalizer block. Both Send and Return jacks
are balanced and run at 0dBu. This is a perfect place
to insert an external reverb unit or profanity delay, but
you have the option to put anything there that you
wish as long as it returns a nominal level.
Direct feed-through occurs with the normalling con-
tacts of the jacks. If you plug into either the SEND or
RETURN jack, the internal path is interrupted. You
need to be sure you have a viable send-return circuit
externally or there will be no audio output from the
Channel.
There is no insert bypass switch. Once plugged in, the
insert is always inserted. If you can’t get any output
from the Channel, make sure the inserted gear is oper-
ating.
2.1 INSTALLATION
The Channel occupies a single rack space (45mm or 1-3/4 inches) of a standard EIA equipment rack.
When rack mounting, use appropriate cushioned rack screws. Never restrict air flow through the device’s vents.
When installing the units into a rack, distribute the units evenly. Otherwise, hazardous conditions may be cre-
ated by an uneven weight distribution. Connect the unit only to a properly rated supply circuit. Reliable earthing
(grounding) of rack mounted equipment should be maintained. Try not to position the Channel directly above
devices that generate excessive heat such as power amplifiers (unless adequately ventilated) or near equipment
with heavy transformer hum fields.
2.2 REAR PANEL VIEW
2.3 AC LINE CONNECTION
Use only a power cord that carries approvals for use in your location. The Channel’s internal power supply is
designed to operate from all nominal power sources from 100 to 240 volts a.c. at 50/60Hz without requiring the
user to change any settings. In case of failure, do not attempt to change the internal fuse because it will never blow
unless the power supply fails catasrophically. The power supply will need to be serviced by a competent service
technician in such a case.

Page 7
Owner’s Manual
2.6 OUTPUT CONNECTORS
There are two output connectors located on the rear
panel: one 1/4” TRS phone type and one XLR-3M type.
They can be used at the same time to feed separate
equipment.
The output level at the XLR is +4dBu impedance bal-
anced, while the TRS balanced/unbalanced jack is
switchable between -10dBV (consumer level) and
+4dBU (professional level).
If you intend to make an unbalanced output from the
XLR jack, simply take “hot” from pin 2 and use pin 1
for ground. Leave pin 3 unconnected or grounded.
Never ground pin 2.
2.7 DIGITAL AUDIO OUTPUTS
The processed mic signal is converted to digital in both
channels at equal level as a mono signal. There is no
provision to externally drive one of the A/D Converter
inputs.
2.8 WORD CLOCK
2.8.1 Clock Select
Synchronization is selected by the Clock Select button
on the front panel. Sample rates of 44.1, 48, 88.2 or
96kHz are supported.
2.8.2 Word Clock IN
This BNC jack is provided to receive your master clock
source. It will accept industry standard Word Clock,
from less than 1 to over 5Vp-p pulse amplitude. It does
not accept AES/EBU or Superclock.
2.8.3 Word Clock OUT
The Channel provides a very accurate internal word
clock generator. When using the Channel as a clock
master, the word clock signal is sent from the BNC
word clock output. Note that the Channel does not
support word clock THRU. External clock signals
received at the BNC input are not routed to the BNC
output. A word clock distribution device should be
used in systems with multiple digital devices.
2.9 POWER SUPPLY
The Channel is internally powered from a standard IEC
power receptacle on the rear panel. Be sure you use a
power cord that is approved for use in your jurisdic-
tion.
Soft-start, overload foldback limiting, and accros-the-
line voltage spike protection is incorporated to protect
the power supply from damage that might be caused
by component failure or power line disturbances. If
the internal fuse blows out, a catastrophic failure has
occurred and simply replacing the fuse will not fix the
problem. Due to the extensive protective measures
used, it is highly unlikely a catastrophic power supply
failure will ever occur. However, if it does, you should
contact the factory or a competent service technician
to affect repairs. There are no user serviceable parts
inside.
100 to 240V~, 50 to 60Hz
ACCEPTABLE POWER RANGE
2.10
Voice artists/actors often find it necessary to clear
the throat, sip a beverage, or cough during narration.
Thus, a convenient mute and unmute jack is provided.
Any standard momentary or latching foot pedal or
switch wired to a mono phone plug will work. Usually,
a desktop box mounted silent pushbutton is preferred,
as it can be accessed most readily.
XLR: AES/EBU 110Ω@ 5Vp-p
RCA: S/PDIF 75Ω@ 1Vp-p
OPTICAL: Toslink S/PDIF encoded for optical fiber.
DIGITAL OUTPUT DEFINITIONS

Channel
Page 8
3.1 USING THE MICROPHONE INPUT
The Channel is perfect for all types of microphones,
either powered or not. We encourage you to try every
mic you own with the Channel.
Many features of the Channel are standard with all pro-
fessional preamps - polarity - pad - etc. Some features
are unique and we hope you will fully exploit them.
3.2 USING THE INSTRUMENT INPUT
The Channel can also be used as a high quality direct
box. When an instrument cable is plugged in to the
Instrument input on the front panel, the rear panel XLR
input is bypassed. This allows the user to keep a micro-
phone connected to the rear panel and simply insert
an instrument cable in to the front panel instrument
input when D.I. functions are required. You will be able
to acheive proper input levels no matter what kind of
pickups are used. Single coil passive pickups will work
just as well as active humbuckers.
3.3 USING PHANTOM POWER
Active microphones that take power through the stan-
dard mic cable fall into a class called “phantom pow-
ered” mics. The power is called “phantom” because it
rides the mic cable invisibly, without interfering with
the audio signal carried on the same wires.
The industry standard phantom power source is posi-
tive 48 volts d.c. supplied to pins 2 and 3 through pre-
cision low noise 6.81KΩ resistors. You may note from
spec sheets that many mics rated for phantom power
actually run at something less than 48 volts. Don’t let
these specifications confuse you. They all run perfectly
well off the standard 48V phantom power source.
Plugging and Unplugging a microphone when phan-
tom power is on can sometimes be dangerous. Some
microphones can be damaged by power inrush. Switch
off the phantom power first. Wait for the mic go silent
before unplugging.
You should be aware of the shock hazard with the
3.0 Using the Channel
FRONT PANEL VIEW
phantom power system. Long, open mic cables that
are disconnected from the preamp while phantom is
on can hold a d.c. charge for long periods of time,
sometimes days, weeks or months. They will act as a
storage capacitor and you can get shocked most rudely
by holding the XLR plug and touching the pins inside.
Also beware of microphone patch bays that may carry
phantom voltage. Don’t hold the patch cord by the
metal parts, only the plastic shell.
CAUTION: Some ribbon mics will be damaged by
phantom power. Some ribbon mics require phantom
power and some just ignore it. Please consult your
manual before connecting a ribbon mic to the Chan-
nel.
3.4 USING THE POLARITY SWITCH
There will be times when you need to reverse the polar-
ity (phase) of a mic signal. Vocalists monitoring them-
selves on headphones will hear a different sound when
the phase is reversed. The reversed phase may sound
fuller and more truthful or hollow and far away. That is
because there is a cancellation of frequencies within the
ear when the external sound from the headphone mixes
with the sound directly conducted to the ear. “Flipping
the phase” can make the problem either more or less
noticeable.
Another time when phase reversing can be helpful is
when using multiple microphones on the same source.
For exapmple, using two microphones on a guitar
speaker cabinet. You may get a “nasal” or hollow
effect when both mics are on. Changing the polarity
of one mic will often clear up the problem. It is always
worth the time to experiment with mic polarity.

Page 9
Owner’s Manual
Figure 4-2 Phase Cancellation Effect
Distance
to Mic2
Distance
to Mic1
Sound
Cancelled
=
3.5 USING THE PAD
An input pad is nothing more than a resistive attenuator
that drops the level coming from the input. Its pur-
pose is to give you a way of preventing overload of the
preamp when incoming signals become excessive.
In the Channel, we provided a pad of 20dB. That
means when the pad is on, the net gain of the preamp
is 20dB lower. There are times that the input may be
overloaded even with the GAIN control set all the way
down. For example, a bass player with active pickups
and an agressive playing style might peak the instru-
ment input. Or a microphone on a kick drum or snare
drum could do it. Engage the pad and 20dB of head-
room will be provided allowing you to better control
the input signal.
3.6 USING LOW CUT
In the real world, mics pick up all sorts of unwanted
low frequencies such as handling noise, wind rumble,
or lectern thumps. We designed into the Channel a
very effective way of cutting out these low frequencies.
Switching on the LOW CUT FILTER rolls off all frequen-
cies below 70Hz at 12dB per octave but places a slight
compensation around 120Hz to improve the low end
phase distortion and perception of remaining bass.
3.7 USING THE PHASE ROTATOR
The Channel’s phase rotator is designed to help reduce
high assymmetric peaks that can occur with certain
audio waves. By reducing the amplitude of assymmet-
ric peaks, the signal can ride louder through compres-
sors and limiters.
Some words of advice: When doing voice work while
wearing headphones, the Phase Rotator will affect
how you hear yourself even though it is not affecting
the actual sound of your voice. That’s because the
body-conducted sound mixes with the sound from the
headphones. When the phase relationship of the two
sounds changes, there will be partial to full cancella-
tion at various frequencies. You should evaluate the
phase rotator by auditioning recorded tracks made
with and without the rotator.
It should also be noted that the effecs of the Phase
Rotator are program dependant and results should be
evaluated with any new signal.
3.8 USING THE COMPRESSOR
The Channel’s compressor is very simple to use. Nev-
ertheless, it is more sophisticated than compressors
with many more controls. The Easyrider compression
automatically adapts to audio waves in a manner that
greatly reduces any pumping effect while it tightens the
average level very flatteringly.
There is only one obvious control: RELEASE. However,
the mic pre’s GAIN control doubles as the compression
drive adjustment. To get more compression depth, run
up more gain. The RELEASE control allows you to
chose the aggressiveness of the compression. For thick
and loud, go faster. For more natural and “open”, go
slower.
The gain reduction is displayed on the Channel’s 10
segment bargraph meter. You may need to boost the
output level to compensate for the gain reduction of
the signal.
3.9 USING THE LOGIC ASSISTED GATE
Aphex’s Logic Assisted Gate solves many common
workflow problems when using gates. The Channel’s
gate trigger is absolutely positive because it’s indepen-
dent from the energy content of the sound peak. The
slightest exceeding of the threshold by the soundwave
triggers the logic that forces the gate’s attack-hold-
release sequences to perform completely and repeat-
ably. That makes finding the right threshold fast and
easy. All you need to set are the threshold and depth
of gating.

Channel
Page 10
If you want complete silence between phrases, then
use the maximum depth. However, if you simply want
to bring down ambience pickup as with multiple open
mics in a room, then use minimal depth. The Gating
LED is triggered when the audio signal is below the
Threshold. If the Threshold is turned all the way up,
the LED may never light. If the Depth is turned all the
way counter clockwise no gating will occur. However,
because the LED is triggered from the Threshold the
LED can be on even though the gate is inactive.
3.10 USING THE DE-ESSER
Certain mics are too harsh in the upper range and
some sounds tend to whistle or splatter. Conventional
de-essers simply detect the presence of any frequency
above a certain tuning point and duck the whole signal
accordingly. The Channel’s de-esser is different. It uses
split band techniques to attenuate only the sibilance,
while leaving the body of the sound alone.
Operation of the de-esser is simple. Just set the thresh-
old to the point where you want the esses to limit out.
Reducing the threshold setting brings down the level of
the esses dynamically. In other words, it’s like an auto-
matic downward shelving equalizer. It stays flat until
the ess level gets too high and then introduces the shelf
at the level needed to limit the sound to the threshold
level. When there is de-essing, the LED is lit.
3.11 USING THE TONE ENHANCEMENT BLOCK
Once the signal passes through the compressor, gate
and de-esser, it encounters the Big Bottom low fre-
quency enhancer, parametric peak/dip section, and
the Aural Exciter top end enhancer. The whole block
is bypassable with the BB/EQ/AX on/off pushbutton.
3.11.1 Big Bottom
Some signals have no low bottom end. In such cases,
the Big Bottom won’t synthesize a new low end for you
and it should not be used. However, voices that con-
tain a deep chest resonance can be augmented by the
Big Bottom.
Start by turning up the BB Amount to 12:00. Then
adjust the BB FREQ to find a frequency that lifts the
bottom. Last, reduce the BB Amount until just the right
touch of bass enhancement is felt.
3.11.2 Parametric Equalizer
This is a familiar and conventional EQ section. You can
adjust the boost/cut, frequency selection and Q.
3.11.3 Aural Exciter
Clarity, presence, and loudness can all be enhanced by
the Aural Exciter.
Start with the AX Ampount at 12:00. Next, sweep the
FREQ to find the best tonal balance. Presence is best
augmented with lower settingss. Air is added with
higher settings. Finally, readjust the AX Amount for
the right amount of brilliance. Be conservative. Use
the BB/EQ/AX on/off switch to compare the original
signal to the enhanced signal.
3.12 USING THE OUTPUT LEVEL CONTROL
Once all the processing is set, the output level may
need to be adjusted. Change the OUTPUT control
to obtain peaks that don’t go above -6dBFS on the
output meter. Check the input meter of the device the
Channels output is plugged in to. If the input device is
cliping, first turn the input devices gain control down.
If the input is still cliping, bring the OUTPUT level of
the Channel down to compensate. Be sure that the
operation level of each device is set properly at either
-10dBV or +4dBu.
3.13 CLIP/MUTE LIGHT
If the LED is flashing RED, then the internal operat-
ing level is too hot. This can only occur if the insert
return signal is too hot or if the parametric equalizer is
boosted way too much. This same LED will also flash
yellow while the Channel is in the MUTED state acti-
vated by the COUGH SWITCH (rear panel jack).

Page 11
Owner’s Manual
4.2 SERVICE INFORMATION
If it becomes necessary to return this unit for repair, you must first contact Aphex Systems, Ltd. for a Return Autho-
rization (RMA number), which will need to be included with your shipment for proper identification. If available,
repack this unit in its original carton and packing material. Otherwise, pack the equipment in a strong carton
containing at least 2 inches of padding on all sides. Be sure the unit cannot shift around inside the carton. Include
a letter explaining the symptoms and/or defect(s). Be sure to reference the RMA number in your letter and mark
the RMA number on the outside of the carton. If you believe the problem should be covered under the terms of the
warranty, you must also include proof of purchase. Insure your shipment and send it to:
Aphex
11068 Randall Street
Sun Valley, CA. 91352
PH: [phone] FAX: [phone]
4.0 Warranty & Service
5.1 Limited Warranty
PERIOD
One year from date of original purchase.
SCOPE
All defects in materials and workmanship.
The following are not covered:
Voltage conversions
Units on which the serial number has been defaced, modified or removed.
Damage or deterioration resulting from: Installation and/or removal of the unit; Accident, misuse, neglect, unau-
thorized product modification; Failure to follow instructions in the Owner’s Manual, User Guide or other official
Aphex documentation; Repair or attempted repair by anyone not authorized by Aphex; Shipping damage – claims
must be presented to the shipper
WHO IS PROTECTED
This warranty will be enforceable by the original purchaser and by any subsequent owner during the warranty
period, so long as a copy of the original Bill of Sale is submitted whenever warranty service is required.
WHAT APHEX WILL PAY FOR
All labor and material expenses for covered items. Aphex will pay all return shipping charges if the repairs are cov-
ered by the warranty.
LIMITATION OF WARRANTY
No warranty is made, either expressed or implied, as to the merchantability and fitness for any particular purpose.
Any and all warranties are limited to the duration of the warrant stated above.
EXCLUSION OF CERTAIN DAMAGES
Aphex liability for any defective unit is limited to the repair or replacement of said unit, out our option, and shall not
include damages of any kind, whether incidental, consequential, or otherwise. Some states do not allow limitations
on how long an implied warranty lasts and/or do not allow the exclusion or limitation of incidental or consequen-
tial damages, so the above limitations and exclusions may not apply to you. This warranty gives you specific rights
which vary from state to state.

Channel
Page 12
OUTPUT
Connector:
Type:
Output Z Balanced:
Output Z Unbalanced:
Nominal Level
Maximum Output Level (MOL):
5.1 GENERAL SPECIFICATIONS
XLR-3M and TRS 1/4” phone jack
XLR is Impedance Balanced (may be used unbalanced); TRS is unbalanced.
XLR: 66Ω
XLR: 33Ω − TRS: 600Ω
XLR: +4dBu; TRS: -10dBV
XLR: +25dBu Unloaded; TRS: +11dBV
5.0 Specifications
All specifications are subject to change without notice.
INPUT
Connector:
Type:
Input Z:
Instrument Connector:
Instrument Input Z:
Type:
Maximum Input Level (MIL):
CMRR:
Nominal Preamp Gain:
Phantom Power:
Pad:
XLR-3F
Transformerless, NPN active balanced, tube second stage
2KΩ nominal
1/4” TS
10MΩ nominal
Transformerless, NPN active balanced, tube second stage
0dBu
Greater than 70dB @ 60Hz
20 to 65dB
+48VDC
20dB
COMPRESSOR
Attack/Release:
Ratio:
Threshold:
Knee:
Program dependent, user variable release baseline.
4:1
Fixed
Medium Hard
INSERT
Connector Type Send:
Connector Type Return:
Nominal Operating Level:
Point of Insertion:
1/4” TRS Phone Jack, Balanced
1/4” TRS Phone Jack, Balanced
0dBu
Between dynamics processing and equalizers.
GATE
Attack:
Hold/Release:
Threshold:
Depth:
0.1 millisecond
300 milliseconds/400 milliseconds
Variable -50 to +20dB
Variable, 1 to 58dB
DE-ESSER
Attack:
Release:
Threshold:
Raio:
Active Band:
0.1 millisecond
100 milliseconds
Variable -20 to +20dB
5:1
4.KHz to 20KHz Linkwitz-Riley 24dB/octave crossover
BIG BOTTOM
Frequency Tune:
MIx:
50Hz to 280Hz
OFF to +12dB
PARAMETRIC EQ
Frequency Tune:
Peak/Dip:
Q Range:
240Hz to 8KHz
+/- 12dB
0.5 to 5
AURAL EXCITER
Frequency Tune:
Mix:
500Hz to 5KHz
OFF to +12dB
ANALOG AUDIO
THD:
IMD:
Freq Resp (FLAT):
<.01% @ +4dBu Out
<.01% @ +4dBu Out
18Hz to 24KHz +/- 1dB
DIGITAL AUDIO
Internal Sample Rates:
External Sample Rates:
Resolution:
Word Clock Input:
Word Clock Output:
Dynamic Range:
Noise Dither:
Level Equivalency:
44.1KHz, 48KHz, 88.2KHz, 96KHz
Automatically syncs to any word clock between 32KHz and 96KHz
24 Bits
BNC Jack, High Z, Captures <1Vp-p to 5Vp-p
BNC Jack, 75 Ohms, 5Vp-p
Digital dynamic range greater than analog front end.
Dithered by analog preamp noise floor. Equivalent to 16-bit digital audio dither.
-20dBFS Digital = +4dBu Analog
OTHER SPECS
Power requirements:
Power Consumption (maximum):
Dimensions:
Depth Behind Front Panel:
Net Weight:
Shipping Weight:
Tube Type:
85 to 260V~, 50-60Hz
12 Watts
19” W x 1.75” H x 8.25” overall depth (482.6mm W x 445mm H x 209.6mm overall depth)
7.5” (190.5mm)
Rack-mounted: 6lbs. (2.73kg)
9lbs. (4.1kg)
12AT7/ECC81 Dual Triode

Page 13
Owner’s Manual
5.2 ARCHITECTURAL SPECIFICATIONS
Basic Description
A single channel processor comprising microphone and nstrument inputs, transformerless tube microphone
preamp, a dynamics processing section and a tone controlling section, in that order. An insertion path shall be
provided between the dynamics procesisng section and the tone controlling section.
The microphone preamp shall comprise the following selectable functions: 1.) +48VDC Phantom Power; 2.) Polar-
ity Reversal; 3.) Selectable 20dB Pad; 4.) Selectable 70Hz 12dB/Octave Low Cut Filter; 5.) Continuous Gain Con-
trol; 6.) Phase Rotator.
The dynamics processing section shall comprise an adaptive dynamic range compressor, a logic assisted noise gate,
and a split-band de-esser.
The tone control section shall comprise a Big-Bottom bass enhancer, an Aural Exciter treble enhancer, and a single
band parametric equalizer.
Physical Properties
The device shall be packaged in an all metal chassis measuring 19” (482.23mm) wide, 1.75” (44.42mm) high,
with an overall depth of 8.25” (210mm). Depth behind the front panel shall be approximately 7” (178mm). The
device shall have a net weight of approximately 6lbs. (2.73kg) and is capable of mounting in a standard electronic
equipment rack.
Power
The unit shall have a self contained power supply operating from the ac line. Primary voltage, connectorization and
agency listings shall be appropriate to meet local requirements.

Channel
Page 14
This product is protected under one or more of the following Aphex patents.
4,578,648
4,633,501
4,843,626
4,939,471
5,115,471
5,155,769
5,334,947
5,359,665
5,422,602
5,424,488
5,450,034
5,463,695
5,483,600
5,485,077
5,612,612
5,737,432
5,848,167
5,896,458
5,898,395
5,930,374
6,266,423
Patent Notice