Crown Audio CH1 User Manual
CH1
CONTRACTOR SERIES
Architectural & Engineering Specifi cations
CH1 (120V, 60 Hz models)
The amplifi er shall be a solid-state two-channel model. Each amplifi er
channel shall have the ability to operate individually, or paired with the
other channel in a bridged confi guration to provide increased output voltage over that of an individual channel output. The outputs shall be switchable for either low impedance (standard speaker load) or high impedance
(distributed speaker line) operation. When in 70V (high impedance)
operation, a 70 Hz high-pass fi lter shall be employed in the signal chain to
prevent step-down transformer saturation.
Front panel controls shall include a rocker switch for selecting power
on and off. Rear panel controls shall include a recessed detented rotary
control for each channel to adjust input level, a recessed switch to select
Stereo or Bridge modes of operation, a recessed switch to select 4/8 ohm
or 70V operation, and a reset switch for the AC mains circuit breaker.
Internal controls shall include a jumper block to allow selection of input
sensitivity of either 0.775V or 26 dB gain as a service option. Sensitivity
shall be factory-set to 1.4V.
Front panel indicators shall include a green LED to indicate that the amplifi er is turned on and power is applied; a red LED for each channel which
shall blink to indicate any of the following 5 conditions: 1) When the
amplifi er is fi rst powered up, until the unit is ready for operation. 2) If
the heatsinks reach a temperature above normal working limits. 3) If the
transformer thermal protection circuit is activated. 4) If the amplifi er wires
develop a short circuit, and 5) should the amplifi er output stage become
non-operational; a red LED for each channel which shall turn on to indicate
when distortion of any type becomes audible in the amplifi er output; and
a green LED for each channel which shall fl ash dimly to indicate when a
low-level signal (> -40 dBm) is present at the input of the amplifi er.
Rear-panel connectors shall include an XLR connector in parallel with a
three-terminal barrier block for each channel for balanced input connection
(on the standard input module); a four-terminal touch-proof barrier block
for each channel for output connection (on the standard output module);
and an RJ11 jack for connection to an external circuit for the purpose of
remotely monitoring fault conditions.
The amplifi er power requirements shall be 120 VAC, 6.3 A at 60 Hz. A
detatchable IEC 15A to NEMA 5-15P AC line cord shall be provided for AC
connection. Typical quiescent power draw shall be 60 watts.
The amplifi er chassis shall be constructed of steel with a durable black
fi nish. The amplifi er shall employ a cooling system consisting of internal
heat exchangers, along with a variable-speed cooling fan which shall operate according to internal thermal demand. Airfl ow through the chassis shall
be from front to rear.
The dimensions of the amplifi er shall allow for 19 inch (48.3 cm) EIA Standard (RS-310-B) rack mounting. The amplifi er shall be 5.25 inches (13.34
cm) tall and 12.25 inches (31.11 cm) deep behind the rack-mounting
surface. The amplifi er shall weigh 40.6 pounds (18.4 kg).
The amplifi er shall be protected against shorted, open or mismatched
loads; overloaded power supplies; excessive temperature; chain destruction phenomena; input overload damage; and high-frequency blowups.
The amplifi er shall protect loudspeakers from input/output DC, large or
dangerous DC offsets and turn-on/turn-off transients.
Nominal input impedance of the amplifi er shall be 20 k ohms, balanced; 10
k ohms, unbalanced.
The power amplifi er shall meet or exceed the following performance criteria
(amplifi er in stereo mode with 8 ohm loads and an input sensitivity of
26 dB gain, 1 kHz at rated power unless otherwise specifi ed): Load impedance (safe with all types of loads): 4 and 8 ohm Stereo; 16 ohm at 70V
Stereo; 8 and 16 ohm Bridge; 32 ohm at 140V Bridge. Voltage gain, 1 kHz,
1.4V sensitivity: 30.5 dB (4/8 ohm); 34 dB (70V). Output Power at 1 kHz
at rated THD; in Stereo mode at 8 ohms: 275 watts per channel; in Stereo
mode at 4 ohms: 450 watts per channel; in Stereo mode, 70V operation:
300 watts per channel; in Bridge mode at 8 ohms: 900 watts; in Bridge
mode, 140V operation: 600 watts. Frequency Response, 20 Hz to 20 kHz at
1 watt: ±0.1 dB. Phase Response: ±15 degrees deviation from linear phase
from 20 Hz to 20 kHz at 1 watt. Signal to Noise Ratio, A-Weighted: Better
than 105 dB below rated 1-kHz power. Total Harmonic Distortion (THD), 1
kHz at rated power: 0.5% or less true THD from 20 Hz to 20 kHz. Intermodulation Distortion (60 Hz and 7 kHz at 4:1): Less than 0.1% at rated power
to 30 dB below rated power at 8 ohms. Damping Factor (8 ohm): Better
than 400 from 10 Hz to 400 Hz. Crosstalk, 20 Hz to 20 kHz: Better than 50
dB below rated power. Common Mode Rejection (CMR): Better than 40 dB
from 20 Hz to 1 kHz. DC Output Offset (Shorted Input): ±10 mV.
The amplifi er shall be designated the Crown CH1.
Crown Audio, Inc.
P.O. Box 1000
Elkhart, IN 46515-1000
TEL: 574-294-8200
FAX: 574-294-8FAX
www.crownaudio.com
Specifi cations subject to change without prior notice. Latest
information available at www.crownaudio.com.
®
Crown
is a registered trademark of Crown International, Inc.
Printed in U.S.A.
© 2005 Crown Audio, Inc.
9/05 131953-1B
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