Crest Audio PRO SERIES 4801 User manual

Product Description
The Crest Audio Model 4801 is a compact, high-power amplifier
designed to meet the most stringent demands of professional use
in concert touring, studio monitoring, high-quality sound rein-
forcement, and professional installations.
A forced-air configuration is used to cool channel heat sinks
mounted in a back-to-back tunnel arrangement. An actively bal-
anced female XLR input connection, Octal Socket, and 5-way
output binding posts are provided for each channel.
The 4801 is fully compatible in design with other Crest Audio
Professional Series amplifiers, Octal Socket Accessories, and the
NexSys®computer-controlled audio system.
Design and Construction
Crest Audio’s no-compromise approach in the 4801’s electrical
design and mechanical construction adds up to the ultimate in
reliability and performance. Only high-grade components are
used for the modular sub-assemblies in their ultra-strong, single
piece steel chassis
4801 Features
• NexSys-ready
• Toroidal power transformer
• Tunnel cooling
• Variable speed DC fan
• High thermal mass heat sinks
• Balanced XLR inputs
• 5-way output binding post connectors
• Stereo/Parallel/Bridged Mono mode selector switch
• Rear panel ground lift jumper
• Extensive protection circuitry:
- Clip Limiting prevents speaker damage with gentle gain
reduction at clip threshold.
- IGM (Instantaneous Gain Modulation) monitors connected
loads to detect conditions that may overstress output
devices, allowing safe operation into nominal 2Ωimped-
ances.
- AutoRamp gradually increases gain to attenuator setting
level when amplifier is turned on.
- Other protection circuitry: comprehensive thermal manage-
ment, and short circuit, DC voltage, turn-on/off transient,
current inrush and sub/ultrasonic input protection.
• Ultra-strong, single piece steel chassis
• Octal Accessory sockets
• Recessed, stepped attenuators
• Front panel circuit breaker/power switch
• Modular construction
• Five-year warranty
(USA, Canada, U.K. & many other countries).
Power Specifications 8ΩStereo 4ΩStereo 2ΩStereo 8ΩBridged 4ΩBridged
1kHz, <0.025% THD+N 400W 575W 700W 1150W 1300W
20Hz-20kHz, <0.05% THD+N†300W 480W 600W 960W 1200W
Figures are Watts per channel, both channels driven. †Continuous sine wave power is limited by current rating of front panel circuit breaker and IGM circuit.
4801
POWER AMPLIFIER
®Crest Professional Series Amplifiers
are fully compatible with the NexSys
Computer-Controlled Audio system.

v. 2.2 3/25/97 B5000004
4801 POWER AMPLIFIER
SPECIFICATIONS
Crest Audio Inc.
100 Eisenhower Dr., Paramus NJ 07652 USA
TEL: [phone] FAX: [phone]
http://www.crestaudio.com
Printed in USA
Architect’s & Engineer’s Specifications
The power amplifier shall have two channels. Each chan-
nel shall deliver a minimum of 300 watts at 8 ohms, 480
watts at 4 ohms and 600 watts at 2 ohms, 20Hz-20kHz,
<0.05% THD+N. In bridged mono mode, it shall deliver
960 watts at 8 ohms and 1200 watts into 4 ohms, 20Hz-
20kHz, <0.05% THD+N.
The amplifier shall be rear-to-front tunnel-cooled, with a
variable-speed DC fan.
The amplifier shall have circuitry to protect itself and the
speaker load from output short circuits, DC voltage on out-
puts, and thermal overload. The amplifier shall include cir-
cuitry to gradually increase gain to attenuator setting lev-
els when the amplifier is turned on, and circuitry for
impedance sensing and clip limiting.
The amplifier shall have a voltage gain of X40 with an
input sensitivity of 1.1V for rated power at 4 ohms. The
hum and noise level shall be greater than 100 dB below
rated output, “A” weighted. SMPTE IMD shall be less
than 0.1 % at rated power, 60Hz and 7kHz. The amplifier
shall have a class H output stage with a modulated power
supply. The frequency response shall be greater than
20Hz-20kHz, +0/-0.3dB (1W/8Ω).
The amplifier shall operate at 100-240V, 50-60 Hz AC
(configured at factory). Maximum current draw shall not
exceed 18 amperes at 120VAC, (circuit breaker limited),
with both channels driving continuously into a 4 ohm resis-
tor.
The amplifier front panel shall include Active, Temp/DC,
Signal Present and Clip/Limit LED indicators for each
channel, a combination power switch/magnetic circuit
breaker and recessed and detented gain pots.
Input connectors shall be actively balanced and have
female XLR-type, 3-pin connectors (pin 3+). Output con-
nectors shall be 5-way output binding posts. Octal sockets
for optional accessory modules and a signal/ground lift
jumper shall be provided.
A rear-panel AC mains cord having an appropriate AC
plug for the intended operating voltage shall be provided
(market dependent).
The packaging of the amplifier shall allow for standard
rack mounting without requiring space between similar
units. Dimensions shall be 3.5" (89mm) high x 19"
(483mm) wide x 15" (381mm) deep. The amplifier shall
have a net weight of 49 lbs. (22.25kg) net. The amplifier
shall be designated the Crest Audio Model 4801.
IN A
IN B
PIN 3+
A
B
SIGNAL
GROUND
LIFT
STEREO
BRIDGE
PARALLEL OUT A
OUT B
USA ONLY
MODEL #
4801 18 AMPS
MAXIMUM
INPUT CURRENT
@ 120V, 60Hz
OUTPUT POWER
IN WATTS PER
CHANNEL, 2Ω
600W
OUTPUT - CLASS 2 WIRING MAY BE USED
6001 21 AMPS 720W
Designed & manufactured in the USA by:
Crest Audio Inc.
100 Eisenhower Dr.
Paramus, New Jersey 07652 USA
RISK OF ELECTRIC SHOCK
DO NOT OPEN
CAUTION
AVIS : RISQUE DE CHOC ÉLECTRIQUE—NE PAS OUVRIR
WARNING TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK DO NOT
EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE.
ATTENTION! POUR ÉVITER LE RISQUE D'INCENDIE OU DE CHOC
ÉLECTRIQUE, NE PLACEZ PAS CETAPPAREILSOUS LA PLUIE OU Á
L'HUMIDITÉ
+
--
BRIDGE
PUSH
PUSH
Rear View
1kHz, <0.025% THD+N 20Hz-20kHz, <0.05% THD+N
400W 300W
575W 480W
1150W 960W
700W 600W
1300W 1200W
60V
85V
20 Hz-20 kHz, -3dB @ 53kHz
20 Hz-20 kHz, +0/-0.2dB
Clip Limit, IGM, AutoRamp, High Temp, short-circuit,
DC voltage, turn-on/off transient, sub/ultrasonic input.
<0.025%
<0.1%
400:1
>60 dB
1.1V RMS
X40
>20kΩ
> -100 dB
> -60dB
H
Female XLR (pin 3+), Octal Socket
5-way output binding posts
80,000 µF
100V-240V, 50-60Hz
1.1A
5.6A
11.46
18.0A
1803 BTU/hr
3385 BTU/hr
Rear to front tunnel heatsink, variable speed DC fan
Front panel: 2 attenuators, circuit breaker/power switch;
Rear panel: mode switch, signal ground lift jumper.
Clip/Limit, Signal, Temp/DC, Active
16 ga. single piece steel chassis, .187" (5mm) alum. front panel
3.5"x19"x15" (16" to rear ears)
89mm x 483mm x 381mm (406mm to rear ears)
54.0 lbs (24.52 kg.), 49.0 lbs (22.25 kg.)
5 years, parts and labor†
8ΩStereo Power
4ΩStereo Power
8ΩBridged Mono Power
2ΩStereo Power
4ΩBridged Mono Power
Max RMS Output Voltage (each channel)
Peak Output Voltage (each channel)
Frequency Response (+0 / -0.3dB, 1W/8Ω)
Power Bandwidth (rated power at 4Ω, 1% THD+N)
Protection Circuitry
THD+N (rated power at 4Ω, 1kHz)
SMPTE IMD (rated power at 8Ω, 60Hz & 7kHz)
Damping Factor (10-400Hz at 8Ω)
Input CMRR (1kHz)
Input Sensitivity (rated power at 4Ω)
Voltage Gain
Input Impedance (balanced)
Hum and Noise (“A” weighted, full power, 4Ω)
Crosstalk (“A” weighted, full power, 4Ω)
Class
Input Connectors (per channel)
Output Connectors (per channel)
Filter Storage
Power Supply (factory configured)
Idle Current Draw (120V)
1/8 Power Curr. Draw (typical music, 120V/4Ω)
1/3 Power Curr. Draw (continuous music, 120V/4Ω)
Max Curr. Draw (circuit breaker rating, 120V/4Ω)
Thermal Emissions (1/8 Power, 4Ω)
Thermal Emissions (1/3 Power, 4Ω)
Cooling
Controls
LED Indicators (per channel)
Construction
Dimensions (Height x Width x Depth)
Gross Weight, Net Weight
Warranty
† USA, Canada, U.K., and many other countries. Power figures are watts per channel, both channels driven. Crest Audio reserves the right
to make improvements in manufacturing or design which may affect specifications. Crest Audio specification literature is available in
downloadable PDF file format; visit our website at http://www.crestaudio.com. ©1997 Crest Audio Inc. 5/21/97
*B5000004*