Crest Audio FXA4801 User manual

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FXA
Power Specifications 8ΩStereo 4ΩStereo 2ΩStereo 8ΩBridged 4ΩBridged
1kHz, 0.01% THD+N 1000W 1800W 2500W 3600W 5000W
20Hz-20kHz, 0.1% THD+N 950W 1700W 2400W 3400W 4800W
Figures are watts per channel, both channels driven.
Preliminary Product Description
The Crest Audio FXA4801 professional power amplifier is
designed to achieve unsurpassed sonic performance and long-
term reliability – even when operating under extreme stress - in
touring or fixed installation applications. The FXA4801 provides
high power output coupled with true clarity, and is well-suited
for high-powered subwoofers and passive full range systems.
Absolute sonic accuracy is the hallmark of every Crest amplifier.
Bass is solid and defined to the limits of audibility, with ample
current reserves delivered by an “over-engineered” power supply
and advanced Class H circuitry. Wide-bandwidth output devices
assure detailed, transparent high frequency response. And, thanks
to Crest’s exclusive IGM circuit, the FXA4801 will drive 2Ω
loads safely without compromise in performance.
Construction and Quality Control
The FXA4801 is built exclusively in Crest’s own USA manufac-
turing facility, with internal components selected for premium
quality and proven durability. Each modular subassembly is
pre-tested, and once assembled, the FXA4801 receives a rigorous
“hot room” burn-in before thorough final pre-shipment checkout
on precision test equipment.
FXA4801 Features
• Crest’s legendary “overbuilt” power supply
• Toroidal power transformer
• Latest generation of high-speed, wide-bandwidth output
devices
• Twin tunnel cooling with back-to-front air flow
• Dual, variable speed DC fans
• Massive, extruded aluminum heat sinks
• Balanced XLR and 1/4-inch (TRS) inputs
• 2 pair of 5-Way Binding Post Outputs
• External switches for stereo/parallel/bridged mono mode,
Pin 2/3 hot (+),
ground lift, and gain/input sensitivity
• TourClass®protection circuits:
- ACL (Active Clip Limiting) prevents speaker damage with
gentle gain reduction at clip threshold.
- IGM (Instantaneous Gain Modulation) monitors speaker
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.
- TourClass protection also includes comprehensive thermal
management, short circuit, DC voltage, turn-on/off tran-
sient, current inrush and sub/ultrasonic input protection.
• Recessed, stepped attenuators
• Front panel circuit breaker switch
• Modular construction
• Three-year warranty
4ΩStereo FXA601 FXA901 FXA1201 FXA2401 FXA3601
1kHz, 0.01% THD+N 250W 435W 600W 900W 1200W
20Hz-20kHz, 0.1% THD+N 200W 400W 500W 800W 1100W
Power Specs: Other FXA Series Power Amplifiers
FXA4801
POWER AMPLIFIER
FXA

v. 1.0 11/6/97
Crest Audio Inc.
100 Eisenhower Dr., Paramus NJ 07652 USA
TEL: [phone] FAX: [phone]
http://www.crestaudio.com
FXA4801 POWER AMPLIFIER
PRELIMINARY SPECIFICATIONS
1kHz, 0.03% THD+N 20Hz-20kHz, 0.1% THD+N
1000W 950W
1800W 1700W
2500W 2400W
3600W 3400W
5000W 4800W
99V
140V
20Hz-20kHz, -3dB@150kHz
20Hz-20kHz, -.2dB/+.2dB
ACL, IGM, AutoRamp, short circuit, DC voltage,
turn-on/off transient, current inrush, sub/ultrasonic input.
<0.03%
<0.01%
800:1
> - 70dB
.775V standard (switchable; see table below)
X115 standard (switchable; see table below)
>20kΩ/>10kΩ
-115dB
> - 80dB
H
Female XLR (pin 2+, switchable for pin 3+), TRS (tip+)
2 pair of 5-way output binding posts
144,000 µF
100V-240V, 50-60Hz
1.5A
6.0A
12.5A
25.0A
7125 BTU/hr
9450 BTU/hr
Back-to-front via 2 rear panel mounted variable-speed DC fans
(filters removable without tools)
Front Panel: 2 attenuators; Rear Panel Switches: signal ground lift,
mode select, gain select, XLR input pin 2/3 hot (+)
Clip/Limit, Signal, Temp/DC, Active
Steel chassis, 16 gauge. Double thickness in rack ear areas.
5.25" x 19" x 17.85" / 133 x 483 x 454mm
82 lbs. (37.23 kg.), 77 lbs. (34.96 kg.)
3 years, parts & labor
8ΩStereo Power
4ΩStereo Power
2ΩStereo Power
8ΩBridged Mono 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)
TourClass®Protection
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 8Ω)
Voltage Gain
Input Impedance (balanced/unbalanced)
Hum and Noise (“A” weighted, full power, 4Ω)
Crosstalk (“A” weighted, full power, 4Ω)
Class
Input Connectors (per channel)
Output Connectors (per channel) (market dependent)
Filter Storage
Power Supply (factory configured)
Idle Current Draw 220V
1/8 Power Curr. Draw (typical music, 220V/4Ω)
1/3 Power Curr. Draw (continuous music, 220V/4Ω)
Max Curr. Draw (circuit breaker rating, 220V/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
Gain Sens
Configurable Gain/Sensitivity Options Factory Standard X115 .775V
Option 1 X40 2.24V
Option 2 X20 4.47V
Architect’s & Engineer’s Specifications
The power amplifier shall have two channels. At 8 ohms, 20Hz
- 20kHz, 0.1% THD+N, it shall deliver a minimum of 950 watts
per channel. At 4 ohms, 20Hz - 20kHz, 0.1% THD+N, it shall
deliver a minimum of 1700 watts per channel. In bridged mono
mode with an 8 ohm load, 20Hz - 20kHz, 0.1% THD+N, it
shall deliver a minimum of 3400 watts.
The amplifier shall have circuitry to protect itself from output
short circuits, thermal overload or other adverse load condi-
tions. The amplifier shall protect speaker loads from DC volt-
age on outputs. The amplifier shall have active clip limiting
and impedance sensing circuitry. Output relays shall protect
the speakers from amplifier failure.
Two rear panel mounted variable speed DC fans (filters
detachable without tools) shall provide back to front air flow
through the chassis.
Each channel shall have a standard (factory-set) input sensitiv-
ity of .775 volt, and shall be fitted with an external switch
which allows the gain to be altered to X20 or X40. The hum
and noise level shall be 115 dB below rated output, “A”
weighted. SMPTE IMD shall be less than 0.01% at rated
power, 60Hz and 7kHz. The amplifier shall have a class H out-
put stage. The frequency response shall be 20Hz-20kHz, +0,
-0.3dB (1W 8Ω).
The amplifier will operate at 100V-240V, 50-60 Hz AC (config-
ured at factory). Maximum current draw shall not exceed 25
amperes at 220VAC (limited by front panel breaker).
Front panel indicators shall include Active, Protect, Signal,
and Clip LED’s for each channel. Front panel attenuators
shall be recessed and detented.
Rear panel input connectors shall be female TRS, and XLR
type, rear-panel switchable for pin 2 (factory setting) or pin 3
positive. Output terminations shall be 2 pair of 5-way output
binding posts. Rear panel switches for ground lift, Stereo/
Parallel/ Bridged Mono mode, XLR polarity and gain selection
shall also be provided.
A rear-panel AC mains cord having an appropriate AC plug
for the intended operating voltage shall be provided.
The packaging of the amplifier shall allow for standard rack
mounting without requiring space between similar units.
Optional rack mount handles will be available. Dimensions
shall be 19" (483mm) wide, 5.25" (133mm) high and 17.85"
(454mm) deep. The amplifier shall weigh 77 lbs. (34.96 kg.)
net, and shall be designated the Crest Audio model FXA4801 .
XLR Pin +
GAIN
Ø
dBu
40x 20x
A
B
+
AB
A
A
ABA
A
B
B
A
B
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A
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+
Designed & manufactured in the USA by:
Crest Audio Inc.
100 Eisenhower Dr.
Paramus, New Jersey 07652 USA
2 3
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Rear
View
Power figures are watts per channel, both channels driven. Crest Audio reserves the right to make improvements in manufacturing or design which may affect specification.