Crest Audio CPX 1 User manual

www.crestaudio.com
CPX Series Power Amplifiers
CPXTM1 | CPXTM2 | CPXTM3Operating
Manual
TEMP
PWR
6
16
20
23
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6
16
20 23
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SIG SIG PWR
CPX 1 POWER AMPLIFIER
GCL
TM
GCL
TM
TM
PWR
ON
TEMP
PWR
6
16
20 23
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6
16
20 23
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SIG SIG PWR
CPX 2 POWER AMPLIFIER
GCL
TM
GCL
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PWR
ON
TEMP
PWR
6
16
20 23
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20 23
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SIG SIG PWR
CPX 3 POWER AMPLIFIER
GCL
TM
GCL
TM
TM
PWR
ON
TM

FCC/ICES Compliancy Statement
This devicecomplies with Part 15 of the FCC. Operation is subject to the following two conditions: (1) this device may
not cause harmful interference, and (2) this device must accept any interference received, that may cause undesired
operation.
Le présent appareil est conforme aux CNR d’lndustrie Canada applicables aux appareils radio exempts de
licence. L’exploitation est autorisée aux deux conditions suivantes: (1) I’appareil ne doit pas produire de
brouillage, et (2) I’utilisateur de I’appareil doit accepter tout brouillage radioélectrique subi, même si le
brouillage est susceptible d’en compromettre le fonctionnement.
Warning: Changes or modifications to the equipment not approved by Crest Audio can void the user’s
authority to use the equipment.
Note –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
instruction manual, may cause harmful interference to radio communications. Operation of this equipment in
aresidential area is likely to cause harmful interference in which case the user will be required to correct the
interference at their expense.
Crest Audio 5022 HWY 493 N.Meridian, MS 39305 [phone] FAX [phone]
2

ENGLISH
3CPX SERIES PROFESSIONAL STEREO POWER AMPLIFIER
INTRODUCTION
Congratulations! You have just purchased one of the world’s finest professional power amplifiers. The CPX amplifier features a two-
way crossover and sub-sonic (low-cut) filter for each channel. Crossover frequencies are fixed at 150 Hz, allowing subwoofers to be
driven at extremely high sound pressure levels, and the filters cut at 40 Hz to prevent low-end rumble. Using proven technology
gained through years of amplifier design, this unit takes advantage of rugged TO-3P output devices mounted on massive aluminum
extrusions and dissipates heat via an extremely quiet and effective two-speed fan. CPX amplifiers are designed to operate at line
voltages as low as 50% of nominal, employing mammoth toroidal power transformers and offering impressive specifications and
features not found on similarly priced competitive units. This amp is designed to drive a 2 Ohmsload per channel, thus achieving
awesome performance levels into 4 Ohms in BRIDGE mode. CPX amplifiers are ruggedly constructed, rack-mountable pieces of gear
with superb patching capability, allowing superior flexibility in application. Front panel features include calibrated, detented gain (dB)
controls and LED indicators for power (PWR), signal presence (SIG), Thermal Protection indicator, and GCL™ activation on each
channel, as well as a rocker mains POWER switch. The back panel contains an IEC connector, line voltage selector switch, dual
primary fuses, and the critical cooling fan opening. This opening should have an adequate supply of cool air and should never be
blocked or restricted. Also on the back panel are the input and output sections, including an input barrier strip for permanent
installations. Each channel input section includes a combo XLR / TRS phone jack connector, THRU/LOW out and HIGH out TRS
jacks, and activation switches for the LOW CUT filter and crossover (150 Hz XOVER). Channel output sections feature dual shock-
proof binding posts and four-conductor twist lock connectors. An additional four-conductor twist lock connector allows BRIDGE mode
output.
UNPACKING
Inspect the amplifier during unpacking. If any damage is found, notify your dealer immediately. Be sure to save the carton and all
packing materials. Should you ever need to ship the unit back to Crest Audio®, one of its service centers, or the dealer; use only the
original factory packing.
INSTALLATION
CPX professional power amplifiers are designed for durability in commercial installations and provide the quality performance required
in studio and home applications. They are two-rack-space units of 15.5" (380 mm) depth designed to mount in a standard 19" rack.
Rear mounting ears are provided for additional support. The minimum rack depth required from the mounting surface is
17" (432 mm) to allow adequate connector clearance.
BASIC SETUP
Before mounting, make sure the line voltage selector is set to the correct voltage (page 5).
Rack mount the amplifier in the location where it is to be used, remembering to allow for adequate access and cooling space. Make
all the connections to the desired INPUT connectors on the desired channel. Select the proper mode configuration (STEREO or
BRIDGE). Connect speakers to the desired OUTPUT connectors.
Make sure the load impedance is greater than 2 Ohms per channel (4 Ohms bridged) to prevent the amplifier from shutting down.
With the POWER switch OFF, connect the IEC cord (8) to the amplifier and then to an outlet of the proper voltage. With both channel
gain controls turned fully counterclockwise, turn the Power switch on, and raise the gain controls to achieve the desired sound level.
Please carefully review this manual to learn about all the features and designed-in behaviors of your new CPX Series power amplifier!
TM

INPUT GAIN (dB)
These controls are used to adjust the input gain of each channel. They determine how “loud” each channel of the power amplifier
will sound for a given input signal level. Maximum input gain is achieved at the fully clockwise setting (+32 dB,40X), and this
setting yields maximum mixer/system headroom. A setting of less than fully clockwise will yield lower system noise at the
expense of mixer/system headroom. Turning the control fully counterclockwise is the “off” setting (-∞). It is always a good idea to
power up any new installation at this setting to protect the system loudspeakers.
POWER LEDS (PWR)
These indicators illuminate when the AC mains power is being supplied to the amp and both channels are operational. If either
channel experiences fault conditions, exceeds safe operating temperature limits, or if the mains circuit breaker trips; both channel
power LEDs will be dark, indicating “shutdown”. If the BRIDGE mode is selected, the PWR indicator on channel B will remain
dark as a positive indication of this mode selection.
SIGNAL ACTIVITY LEDS (SIG)
These indicators illuminate when the associated channel output signal level exceeds 1 V RMS.
GCL ACTIVE LEDS
These indicators illuminate when GCL compression is taking place in the associated channel. If the rear panel GCL switch is
depressed, then GCL is defeated and these LEDs indicate clipping is occurring in the corresponding channel. The Crest Audio
GCL compression system will be covered in greater detail later in this manual.
Thermal Protect LED
This indicator illuminates when the thermal sensor on either heatsink reaches approximately 90 degrees C, at which point, the
amplifiers are muted while the fan remains on high speed. If this happens repeatedly, either reduce the load on the amplifier
(detach one of the speakers), or supply additional cooling to the amplifier, such as a fan. When rack mounting, it is helpful to
leave 1 RU open above and below the amplifier to prevent heat buildup from adjacent units.
POWER SWITCH
This heavy-duty, rocker-type switch turns on the mains power to the amplifier. When the mains power is applied, there is a delay
in activation of the unit. This reduces/eliminates the turn-on transients associated with the system equipment connected to the
amplifier and protects loudspeakers.
DUAL PRIMARY FUSE
In order to accommodate line voltage switching, the power transformer is designed with two primaries that can be placed in
series or parallel by means of the line voltage selector switch. Each primary is individually fused, so there is no need to change
fuse values when a different line voltage is selected. It is important to use the fuse values specified on the rear panel. The fuses
are provided to limit current to the associated transformer primary winding, and protect it from overheating and possible
destruction due to fault conditions in the unit. The trip current values have been carefully chosen to allow reasonable continuous
power output performance, while still protecting the power transformer. These fuses should not open unless there is a fault in the
amplifier circuitry that causes excessive mains current draw. However, abnormal conditions such as a short circuit on either or
both channels, or continuous operation at overload or clipping (especially into 2 Ohmsloads per channel or 4 Ohmsbridge load)
can cause the fuses to open. If this occurs, UNPLUG from the AC POWER source before replacing the fuses, after waiting a
brief period of time to allow the unit to cool down. Efforts should be made to correct the cause of the overload, first by
disconnecting one output at a time, and then one speaker at a time until the bad cable or damaged speaker is isolated. If the
fuses open instantly each time you attempt to turn the unit on, it should be taken to a qualified Crest Audio Service Center for
repair. 4
TEMP
PWR
6
16
20
23
26
29
32
6
16
20 23
26
29
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SIG SIG PWR
CPX 1 POWER AMPLIFIER
GCL
TM
GCL
TM
TM
PWR
ON
1
2
3
4
5
6
Front Panel
16
2
34
5
7

5IEC MAINS CONNECTOR
This is a standard IEC power connector. An AC mains cord having the appropriate AC plug and ratings for the intended
operating voltage is included in the carton.
U.S. DOMESTIC AC MAINS CORD
The mains cord supplied with the unit is a heavy-duty, three-conductor type with a conventional 120 VAC plug with ground pin.
It should be connected to an independent circuit capable of continuously supporting at least 15 amps. This is particularly critical
for sustained high-power applications. If the outlet used does not have a ground pin, a suitable grounding adapter should be
used and the third wire grounded properly.
Never break off the ground pin on any equipment. It is provided for your safety.
The use of extension cords should be avoided but, if necessary, always use a three-wire type with at least a #14 AWG
wire size. The use of lighter wire will severely limit the power capability of this amplifier. Always use a qualified
electrician to install any new electrical equipment. To prevent the risk of shock or fire hazard, always be sure that the amplifier
and all associated equipment is properly grounded.
NOTE: FOR UK ONLY
If the colors of the wires in the mains lead of this unit do not correspond with the colored markings identifying the terminals in
your plug, proceed as follows: (1) The wire that is colored green and yellow must be connected to the terminal that is marked
by the letter E, the earth symbol, colored green, or colored green and yellow. (2) The wire that is colored blue must be
connected to the terminal that is marked with the letter N or the color black. (3) The wire that is colored brown must be
connected to the terminal that is marked with the letter L or the color red.
LINE VOLTAGE SELECTOR SWITCH
The CPX series power transformer is designed with two primaries that can be placed in series or parallel by means of the line
voltage selector switch. It is accessible by loosening one screw and rotating the transparent guard out of the way. Please be
sure this is set to the proper voltage for your area before turning the amplifier on for the first time.
BINDING POST OUTPUTS
Shockproof binding post speaker outputs are provided on the CPX amplifier. For each channel, the outputs are in parallel and
the speaker connection cables can be terminated with banana plugs or stripped wires for use in the binding post terminals, or
can be connected using the twist lock outputs (11). For sustained high-power applications, either outputs can be used;
however, exercise care to assure the correct speaker polarity. The red binding posts are the signal outputs from each channel,
and the black binding posts are chassis ground. The red binding post should be connected to the positive inputs of the
associated loudspeakers. For BRIDGE mode operation, only the red binding posts are used, and the loudspeaker load is
connected between the two red posts, with CH A having positive polarity and CH B having negative polarity.
WARNING. Regardless of what connections are used, the minimum parallel speaker load should always be limited to
2 Ohms per channel, or 4 Ohms when in BRIDGE mode. Operation at loads of 4 Ohms per channel, or 8 Ohms
BRIDGE mode, is more desirable for sustained operation applications because the amplifier will run much cooler with
this load. Operation above 4 Ohms per channel and even open-circuit conditions can always be considered safe, but sustained
operation at loads below 2 Ohms could result in temporary amplifier shut down due to the thermal limit circuitry.
TWIST LOCK OUTPUTS
CPX amplifiers utilize three 4-conductor twist lock connectors, one for each channel and one for BRIDGE mode. Please refer
to the BRIDGE MODE section of this manual before attempting to use this mode. For each channel twist lock, the same
impedance rules apply as with the binding posts. Internally, all the twist locks are wired in the “high current” configuration, with
13
INPUTS
CHANNEL ACHANNEL ACHANNEL B
CHANNEL B
LINE OUTS
BRIDGE
SPEAKER OUTPUTS
220-240V
T 15AL
250V
115V
MOUNT IN RACK ONLY - INSTALLER SUR
SUPPORT DE MONTAGE SEULEMENT
BRIDGE
+
++
_
_ _
A
B
+
-
+
-
40 Hz
GND
40 Hz
150 Hz
X-OVER
150 Hz
X-OVER
HIGH
OUT
LOW
OUT
HIGH
OUT
LOW
OUT
THRU
THRU
BRIDGE
GCL
ENABLE
DEFEAT
STEREO
BRIDGE
50/60 Hz
FUSE
450 WATTS CLASS 2 WIRING
100V RMS
A PRODUCT OF
CREST AUDIO INC.
5022 HWY 493
MERIDIAN, MS 39305 USA
WWW.CRESTAUDIO.COM
DESIGNED AND ENGINEERED
IN U.S.A.
MADE IN CHINA
TM
7
Rear Panel
8
8
9
10
10
11
13
12
14 18
19 16 15
17
20
9
11

612
13
14
15
16
17
18
19
Rear Panel
pins 1+ and 2+ in parallel, and pins 1- and 2- in parallel. For the CHANNEL A and CHANNEL B twist locks, the respective channel
output appears on pins 1+ and 2+. Pins 1- and 2- are chassis ground. For the BRIDGE twist lock, CHANNEL A appears on pins 1+
and 2+, and CHANNEL B appears on pins 1- and 2-. Always check the twist lock connector wiring carefully before using.
MODE SWITCH
This switch is best changed when the amplifier is off. It is used to select STEREO or BRIDGE mode operation. It is a recessed
push-push type, requiring a small tool to activate. The IN position is BRIDGE mode; the OUT position is STEREO mode. Exercise
care when selecting the BRIDGE mode. Accidental selection of this mode could damage loudspeakers, particularly in bi-amped
systems. Amplifier BRIDGE mode theory will be covered later in this manual.
GCL (Gain Comparator Limiter) SWITCH
This switch is used to enable or defeat the GCL limiter circuitry. It is also a conventional push-push type, requiring a small "tool" to
activate. The IN position is DEFEAT; the OUT position is ENABLE. Normally, the GCL function should be enabled to minimize the
possibility of either or both channels going into clipping or overload. With this feature defeated, a severe overload could cause the
mains circuit breaker to trip. The Crest GCL limit-ing system will be covered in greater detail later in this manual.
FAN GRILLE
A two-speed DC fan supplies cool air to the amplifier. THIS INTAKE SHOULD NEVER BE BLOCKED! The fan switches to
high speed automatically when the unit requires additional cooling. At idle and cool, the fan runs at low speed. The fan should never
stop unless the amplifier is switched OFF or the AC mains power source is interrupted, or the thermal breaker in the transformer
has tripped due to excess heating. The thermal breaker in the transformer is self-resetting once the excess heat has dissipated.
INPUT BARRIER STRIP
A barrier strip is provided for input connections using bare wire or spade lug connections. CPX amplifiers employ low-noise,
electronically balanced input circuitry. This circuitry offers a very wide dynamic range capable of handling virtually any input signal
level, while providing excellent common mode rejection to minimize hum and reduce interference. This strip accepts balanced and
unbalanced audio signals. The "+" and "-" terminals are the positive and negative inputs to the respective channels. The GND
terminal is the common ground to both channel inputs. For use with an unbalanced source, connect the "-" input terminal of the
channel to ground with a jumper. If the "-" input is left floating, a 6 dB loss in channel gain will result and the floating input terminal
may pick up outside noise.
COMBO INPUT CONNECTOR
The combo connector offers both female XLR and 1/4" phone jack balanced inputs for each channel. The XLR is wired with pin 1
as ground, pin 2 positive input, and pin 3 negative input. The 1/4" phone jack is a tip/ring/sleeve (3-conductor) type, with the tip
being positive input, the ring negative input, and the sleeve ground. It is important to realize that the XLR, 1/4" jack, and barrier strip
inputs are all in parallel; therefore a balanced input to the associated channel can be accomplished using a male XLR, a
3-conductor phone jack, or bare wires connected to the barrier strip.
As an alternative, the 1/4" input can also be used with a regular tip/sleeve (2-conductor) type plug commonly found on
single-conductor shielded patch cords. In this case, the input becomes unbalanced, with the tip as positive input, and the sleeve
ground (the ring being grounded by the sleeve of the plug).
40 Hz SWITCH
This switch is used to activate the high-pass filter for the corresponding channel. It is again a push-push type switch, requiring a
small tool to activate. The IN position routes the input signals through the 40 Hz high-pass filter, while the OUT position bypasses
the filter. This filter cuts extremely low frequencies, protecting speakers from over-excursion. The filter low-frequency rolloff is 12 dB
per octave. The high-pass filter for each channel will function independently of the crossover function to be discussed next.
CROSSOVER SWITCH (150 Hz XOVER)
This switch is used to activate the 150 Hz crossover for the corresponding channel. It is also a push-push type switch and requires
a small tool to activate. The CPX offers two 150 Hz crossovers. These are designed for use when a subwoofer is added to the
system.
With the switch IN, the input signals are routed through the crossover, and the low frequencies are automatically sent to the
corresponding channel. At the same time, the high frequencies are sent to the HIGH OUT (20) jack and must then be patched to an
INPUT of the other channel of this amplifier or to another amplifier input to complete the bi-amped system. Additionally, the low
frequencies are sent to the THRU/LOW OUT (19) jack, and can be patched to other amplifier inputs to permit even larger systems.
With the switch OUT the crossover is defeated, and the input signal is routed to the line level THRU output jack. The crossover
frequency is fixed at 150 Hz and cannot be changed. The crossover configuration is a 4th order Linkwitz-Riley approximation.
THRU/LOW OUT JACKS
As per previous crossover discussion, this 1/4" jack supplies low-frequency out signals from the activated crossover for patching to
additional power amplifier inputs, providing added flexibility in larger bi-amped systems. When the crossover function is not
activated, this jack converts to a THRU function, where the output of the electronically balanced input circuitry is supplied to this
jack. The THRU function provides the means to patch a full range input signal to the other input of this amplifier (parallel mode), or
to other amp inputs in the same rack. This function allows one balanced mixer feed to be connected to the amp via the desired
balanced input connector (XLR, 1/4", Barrier), and then further distributed locally. Regardless of the crossover switch position, this
1/4" jack provides an impedance balanced (TRS) output. Although 2-conductor balanced (TRS) cables will provide better noise
immunity, single conductor shielded (tip/sleeve) cables can also be used.

7HIGH OUT JACKS
Again, as per previous crossover discussion, this 1/4" jack supplies high frequency out signals from the activated crossover for
patching to this amplifier and/or additional power amplifier inputs. Unlike the low-frequency crossover output, that is automatically
routed to the associated channel, the high-frequency output signal must be patched to some suitable input in order to complete the
bi-amped system. This 1/4" jack provides an impedance balanced (TRS) output. Although 2-conductor balanced (TRS) cables will
provide better noise immunity, single conductor shielded (tip/sleeve) cables can also be used.
INDUSTRIAL AND COMMERCIAL INSTALLATIONS
For commercial and other installations where sustained high-power operation is required, the amplifiers should be mounted in a
standard 19" rack. It is a good idea to leave a rack space between each amplifier in the stack to prevent heat builup between units
and induced hum from transformer magnetic fields. Regardless, an adequate cool air supply must be provided for the amplifier
when rack mounted. The internal fan must have a source of air that is not preheated by other equipment. The amplifier will start up
in low speed fan operation and will normally stay at low speed unless sustained high-power operating levels occur. Then, as
temperatures in the amplifier heat sinks increase, thermal-sensing circuitry will cause high-speed operation to occur. Depending
upon signal conditions and amp loading, high-speed fan operation may continue or the fan may cycle continuously between high
and low. This behavior is by design. If cooling is inadequate, however, the amplifier thermal-sensing system may cause temporary
shut down of the unit, indicated by the front panel THERMAL PROTECT LED. Inadequate cooling may be due to preheated air,
reduced air flow resulting from blockage of inlet/outlet ports, amplifier overload, or short circuit conditions. Depending upon the
available cooling air, operation should be restored relatively quickly, and the power LEDs on both channels will again be
illuminated. In any event, action should be taken to correct the cause of the thermal shutdown. If the amplifier is not severely
overloaded or shorted and air flow is normal in and out of the amplifier, then steps should be taken to provide a cooler
environment for all the amplifiers.
As a general rule, most home and studio requirements will never cause high-speed fan operation. High-speed operation may
indicate that you have not taken the necessary steps to provide adequate cooling. The CPX Series should never be operated in a
fully enclosed cabinet.
BRIDGE MODE
When a 2-channel amplifier is operated in the Bridge mode, it is converted into a single-channel unit with a power rating equal to
the sum of the power rating for each channel, at a load of twice that of the single-channel rating. For example, the CPX 2 is rated
at 450 Watts RMS per channel into 2 Ohms. The Bridge rating is 900 Watts RMS into 4 Ohms (minimum load). Bridge mode
operation is accomplished by placing the MODE switch in the BRIDGE position, using only the BRIDGE twist lock connector or the
red binding posts for the output, and using the CHANNEL A input. All CHANNEL B input functions are defeated and serve no
purpose now. Bridge mode operation can be used to drive sound distribution systems in very large public address applications.
Another common use for the Bridge mode is in subwoofer applications where very high power levels are required to reproduce
extremely low frequencies with adequate headroom. Such enclosures usually contain 2 or 4 loudspeakers to handle the power
levels involved. When using Bridge mode, the connected enclosure impedance must be 4 or 8 Ohms — never below 4 Ohms.
GCL
Crest Audio's patented GCL (Gain Comparator Limiting) circuit enables the sound technician to maximize the performance of the
amplifier/speaker combination by preventing the power amplifier from running out of headroom (clipping). This limiting system is
activated by a unique circuit that senses signal conditions that might overload the amplifier and activates compression (reduces the
channel gain) when clipping is imminent. The threshold of limiter is clipping itself, and no specific threshold control is used. This
technique effectively utilizes every precious watt available for the power amplifier to reproduce the signal, while at the same time
minimizing clipping and distortion. GCL significantly reduces the potential of loudspeaker degradation and damage, and is the most
effective, automatic, hands-off approach to the problem of power amplifier clipping.
20
Rear Panel
STAGE OVERCURRENT PROTECTION
Another unique feature of the CPX Series power amplifiers is a 2 stage overcurrent protection scheme. The first stage of
overcurrent protection uses a preset current threshold to prevent excessive current through the output devices when driving loads
of 2 Ohms impedance or higher (4 Ohms bridged). The second stage dramatically decreases the output of the amplifier if the
detected load impedance is one Ohm or less, effectively muting the affected channel and keeping the output devices within their
Safe Operating Area.
When the second stage current limit engages, output will be extremely weak, and the front panel GCL LED will be glow steadily,
pulsing with the input signal, but dimly. The signal will not return until the overload is removed and the input level is reduced below
clipping. This behavior is by design. If this condition occurs, try reducing the input level so that the GCL LED only lights on the
loudest peaks. If it continues, inspect for shorted speaker cables, or a total load impedance of less than 2 Ohms per channel / 4
Ohms bridged.

CPX 1 CPX 2 CPX 3
Stereo* Mode
2 Ω, 1 kHz, 1% THD (RMS per channel) 300 W 450 W 625 W
4 Ω, 1 kHz, 1% THD (RMS per channel) 480 W 690 W 1,250 W
8 Ω, 1 kHz, 1% THD (RMS per channel) 290 W 430 W 750 W
Bridge* Mode (Mono)
8 Ω, 1 kHz, 1% THD (RMS) 960 W 1,380 W 2,500 W
4 Ω, 1 kHz, 1% THD (RMS) 600 W 900 W 1,250 W
2 Ω 2 Ω 2 Ω
50 V 60 V 80 V
Minimum Load Impedance
Maximum RMS Voltage per channel
Frequency Response +0, -2 dB @ 1 W
Stereo mode, both channels driven +0, 12 Hz - 35 kHz 12 Hz - 35 kHz 12 Hz - 35 kHz
-2 dB @ 1 W
Hum & Noise
"A" weighted, reference to rated power > 88 dB > 88 dB > 88 dB
@ 8 Ω
Crosstalk
@ 1 kHz, at rated output power @ 8 Ω > -55 dB > -55 dB > -55 dB
1.08 V 1.17 V 1.26 V
Input Sensitivity RMS Voltage
@ rated output power, 4 Ω
Input Impedance
Balanced, XLR 10 kΩ 10 kΩ 10 kΩ
40X (+32 dB) 40X (+32 dB) 40X (+32 dB)
(pin 2 positive) & TRS 1/4" Jack
Overall System Gain per Channel
Distortion (THD)
Stereo Mode, both channels driven, < 0.1% < 0.1% < 0.1%
> 12 V/µs > 12 V/µs > 12 V/µs
20 Hz - 20 kHz, 10 dB, 4 Ω
Slew Rate
Damping Factor 8 Ω, 20 Hz -2 kHz
Stereo Mode, both channels driven, > 250:1 > 250:1 > 250:1
8 Ω, 20 Hz -2 kHz
Class AB Class AB Class H
Yes Yes Yes
Topology
Limiter (GCL - switchable)
Input Connectors
Input
Link
2 x 3-pin XLR - 1/4" Jack (TRS) Combo Barrier Strip
2 x 1/4" Jack (TRS) High Out, 2 x 1/4" Jack (TRS) Low Out / Thru
Output Connectors
Stereo Mode
Bridge Mode
Crossover
Switchable per channel
2 x 4-pin Twist-Lock & Binding Post
1 x 4-pin Twist-Lock & Binding Post
150 Hz (4th order Linkwitz-Riley)
-3 dB @ 40 Hz (12 dB per Octave)
Stereo & Bridge Mode
"Full short circuit, open circuitLow Cut
Switchable per channel
Mode Select
Stable into any load" Over-temp thermal RF Stable into any load" Load "Turn on/off mutingDC (triac crowbar)Low-cut filter" "Turn on/off mutingDC (triac crowbar)Low-cut filter" "Turn on/off mutingDC (triac crowbar)Low-cut filter"Power Consumption Stereo Mode, both channels driven @ 1/8 rated output power, 4 Ω 450 W 680 W 600 WMains Voltage "Dual VoltageSelector switch 220-240 & 115 V AC, 50/60 Hz" "Dual VoltageSelector switch 220-240 & 115 V AC, 50/60 Hz" "Dual VoltageSelector switch 220-240 & 115 V AC, 50/60 Hz"Mains Connector IEC IEC IECLED Indicators "GCL™/Clipping - RedSignal - YellowThermal Protect - RedPower - Green" "GCL™/Clipping - RedSignal - YellowThermal Protect - RedPower - Green" "GCL™/Clipping - RedSignal - YellowThermal Protect - RedPower - Green"Dimensions & Weight Net Weight "40 lbs18.2 kg" "45 lbs20.5 kg" "49 lbs22.3 kg" Dimensions (HWD) "3.5"" x 19"" x 15.5""89 mm x 483 mm x 380 mm" "3.5"" x 19"" x 15.5""89 mm x 483 mm x 380 mm" "3.5"" x 19"" x 15.5""89 mm x 483 mm x 380 mm"* Repetitive burst @ 20 ms 8 Specifications Rated Power @ 120 VAC or 240 VAC

Cooling System
Temperature dependent, 1 x Two-Speed DC Fan
air flow - back to front
Protection
Amp Full short circuit, open circuit, Over-temp thermal, RF, Stable into any load
Turn on/off muting, DC (triac crowbar), Low-cut filter
Load
Power Consumption
Stereo Mode, both channels driven 550 W 680 W 600 W
@ 1/8 rated output power, 4 Ω
Dual Voltage, Selector switch 220-240 & 115 V AC, 50/60 Hz
Mains Voltage
Mains Connector
LED Indicators
Dimensions & Weight
Net Weight 40 lbs (18.2 kg)
GCL™/Clipping - Red
Signal - Yellow
Thermal Protect - Red
Power - Green
45 lbs (20.5 kg) 49 lbs (22.3 kg)
Dimensions (HWD) 3.5" x 19" x 15.5" (89 mm x 483 mm x 380 mm)
* Repetitive burst @ 20 ms
Specifications subject to change without notice!
CPX 1 CPX 2 CPX 3
9Specifications
IEC

10INPUTS
CHANNEL ACHANNEL ACHANNEL B
CHANNEL B
LINE OUTS
BRIDGE
SPEAKER OUTPUTS
220-240V
T
15AL
250V
115V
MOUNT IN RACK ONLY - INSTALLER SUR
SUPPORT DE MONTAGE SEULEMENT
BRIDGE
+
++
_
_ _
A
B
+
-
+
-
40 Hz
GND
40 Hz
150 Hz
X-OVER
150 Hz
X-OVER
HIGH
OUT
LOW
OUT
HIGH
OUT
LOW
OUT
THRU
THRU
BRIDGE
GCL
ENABLE
DEFEAT
STEREO
BRIDGE
50/60 Hz
FUSE
450 WATTS CLASS 2 WIRING
100V RMS
A PRODUCT OF
CREST AUDIO INC.
5022 HWY 493
MERIDIAN, MS 39305 USA
WWW.CRESTAUDIO.COM
DESIGNED AND ENGINEERED
IN U.S.A.
MADE IN CHINA
TM
T
)
1
INPUTS
CHANNEL ACHANNEL ACHANNEL B
CHANNEL B
LINE OUTS
BRIDGE
SPEAKER OUTPUTS
220-240V
T
15AL
250V
115V
MOUNT IN RACK ONLY - INSTALLER SUR
SUPPORT DE MONTAGE SEULEMENT
BRIDGE
+
++
_
_ _
A
B
+
-
+
-
40 Hz
GND
40 Hz
150 Hz
X-OVER
150 Hz
X-OVER
HIGH
OUT
LOW
OUT
HIGH
OUT
LOW
OUT
THRU
THRU
BRIDGE
GCL
ENABLE
DEFEAT
STEREO
BRIDGE
50/60 Hz
FUSE
450 WATTS CLASS 2 WIRING
100V RMS
A PRODUCT OF
CREST AUDIO INC.
5022 HWY 493
MERIDIAN, MS 39305 USA
WWW.CRESTAUDIO.COM
DESIGNED AND ENGINEERED
IN U.S.A.
MADE IN CHINA
TM
T
)
1
2
Configurations

11INPUTS
CHANNEL ACHANNEL ACHANNEL B
CHANNEL B
LINE OUTS
BRIDGE
SPEAKER OUTPUTS
220-240V
T
15AL
250V
115V
MOUNT IN RACK ONLY - INSTALLER SUR
SUPPORT DE MONTAGE SEULEMENT
BRIDGE
+
++
_
_ _
A
B
+
-
+
-
40 Hz
GND
40 Hz
150 Hz
X-OVER
150 Hz
X-OVER
HIGH
OUT
LOW
OUT
HIGH
OUT
LOW
OUT
THRU
THRU
BRIDGE
GCL
ENABLE
DEFEAT
STEREO
BRIDGE
50/60 Hz
FUSE
450 WATTS CLASS 2 WIRING
100V RMS
A PRODUCT OF
CREST AUDIO INC.
5022 HWY 493
MERIDIAN, MS 39305 USA
WWW.CRESTAUDIO.COM
DESIGNED AND ENGINEERED
IN U.S.A.
MADE IN CHINA
TM
INPUTS
CHANNEL ACHANNEL ACHANNEL B
CHANNEL B
LINE OUTS
BRIDGE
SPEAKER OUTPUTS
220-240V
T
15AL
250V
115V
MOUNT IN RACK ONLY - INSTALLER SUR
SUPPORT DE MONTAGE SEULEMENT
BRIDGE
+
++
_
__
A
B
+
-
+
-
40 Hz
GND
40 Hz
150 Hz
X-OVER
150 Hz
X-OVER
HIGH
OUT
LOW
OUT
HIGH
OUT
LOW
OUT
THRU
THRU
BRIDGE
GCL
ENABLE
DEFEAT
STEREO
BRIDGE
50/60 Hz
FUSE
450 WATTS CLASS 2 WIRING
100V RMS
A PRODUCT OF
CREST AUDIO INC.
5022 HWY 493
MERIDIAN, MS 39305 USA
WWW.CRESTAUDIO.COM
DESIGNED AND ENGINEERED
IN U.S.A.
MADE IN CHINA
TM
Configurations

stranded cable length
0.3mm2
0.5
0.75
1.5
2.5
4.0
2.9%
1.74
1.16
0.58
0.35
0.22
5.6%
3.4
2.3
1.16
0.70
0.44
10.8%
6.7
4.5
2.3
1.39
0.87
0.5mm2
0.75
1.5
2.5
4
6
4.3%
2.9
1.45
0.87
0.55
0.37
8.2%
5.6
2.9
1.74
1.09
0.73
15.5%
10.8
5.6
3.4
2.2
1.45
0.5mm2
0.75
1.5
2.5
4
6
8.24%
5.6
2.9
1.74
1.09
0.73
5.5%
10.8
5.6
2.9
1.74
1.09
28%
19.9
10.8
6.7
4.3
2.9
0.75mm2
1.5
2.5
4
6
10
15.5%
8.2
5.1
3.2
2.2
1.31
0.73%
15.5
9.8
6.3
4.3
2.6
45%
28
18.2
12.0
8.2
5.1
2meters
5meters
10meters
30meters
wire gauge power loss
8Ohmsload 4Ohmsload 2Ohmsload
12Wire Gauge

stranded cable length
18AWG
16
14
12
10
0.81%
0.51
0.32
0.20
0.128
1.61%
1.02
0.64
0.40
0.25
3.2%
2.0
1.28
0.80
0.51
18AWG
16
14
12
10
1.61%
1.02
0.64
0.40
0.25
3.2%
2.0
1.28
0.80
0.51
6.2%
4.0
2.5
1.60
1.01
18AWG
16
14
12
10
8
6.2%
4.0
2.5
1.60
1.01
0.60
11.9%
7.7
5.0
3.2
2.0
1.20
22%
14.6
9.6
6.2
4.0
2.4
18AWG
16
14
12
10
8
11.9%
7.7
5.0
3.2
2.0
1.20
22%
14.6
9.6
6.2
4.0
2.4
37%
26
17.8
11.8
7.7
4.7
5feet
10feet
40feet
80feet
wire gauge power loss
8Ohmsload 4 Ohmsload 2Ohmsload
13Wire Gauge

Logo referenced in Directive 2002/96/EC Annex IV
(OJ(L)37/38,13.02.03 and defined in EN 50419: 2005
The bar is the symbol for marking of new waste and
is applied only to equipment manufactured after
13 August 2005
www.crestaudio.com
Features and specifications subject to change without notice.
Crest Audio 5022 HWY 493 N. Meridian, MS 39305 [phone]FAX [phone]
© 2022 - Rev F1_01072022