Crown 280-MA Brochure

280MA

COMMERCIAL AUDIO SERIES

Architectural & Engineering Specifi cations

280MA

The Crown® 280MA shall be a mixer-amplifi er for commercial and
industrial audio. It provides 4-ohm and constant-voltage outputs (70V and
100V).

The 280MA has 8 inputs and dual 80W power amplifi ers for two-zone
systems.

Specifi cations

The 280MA shall have the following specifi cations:
Minimum guaranteed power into 4 ohms or 70V/100V output: 80W maxi-

mum power at 1 kHz with 0.5% THD. Frequency Reponse (at 1 watt from
4-ohm tap, 70 Hz - 19 kHz): +/- 1 dB. Frequency Response (at line out,
20 Hz to 20 kHz): +/- 1 dB. Power Bandwidth (at 4-ohm tap, 2 dB below
maxium 1 kHz power): 50 Hz to 20 kHz with < 0.5% THD. Signal to Noise
Ratio (ref. to rated power, master volume at minimum): 85 dB. DC Output
Offset: < ±5 mV. THD: Less than 0.5% at rated power at 1 kHz. Input
Sensitivity (for full output at maximum gain): Balanced mic inputs 3 mV,
balanced line inputs 800 mV, RCA connectors 400 mV. Input Impedance
(nominal): Mic 400 ohms, line 100 kilohms, RCA 50 kilohms. Crosstalk:
–70dB at 1kHz. Line Output Level (nominal): 1V into 10 kilohms. Phantom
Power: 15 VDC. AC Line Voltages Available: 100V 50/60 Hz, 120V 60 Hz,
220V 50/60 Hz, 230V 50/60 Hz, 240V 50/60 Hz. Operating Temperature/
Humidity: 0 degrees C to 40 degrees C at 95% relative humidity (non-con­densing). Storage Temperature: –20 degrees C to 85 degrees C.

Front Panel Controls and Indicators

Front panel controls and indicators shall include the following:
Power Switch: Pushbutton on-off switch. Input Volume Controls: eight

microphone/line, detented potentiometers with knobs. Output Volume
Controls: One per output channel, detented potentiometer with knob. Tone
Controls: Bass and Treble non-detented recessed potentiometers on each
input channel, Bass ±10 dB at 100 Hz, Treble ±10 dB at 10 kHz. Power Indi­cator: Blue LED indicates power on. Input Signal Presence Indicator: Green
LED, one for each input channel, illuminates when input signal exceeds
100 mV (45 dB below full power) from the 4-ohm tap; shall not respond to
signals from the AMP INPUT connector. Output Signal Presence Indica­tor: Green LED, one for each input channel, illuminates when input signal
exceeds 100 mV (45 dB below full power) from the 4-ohm tap; shall not
respond to signals from the AMP INPUT connector. Clip Indicators: Red
LED, one per output channel, illuminates at threshold of audible distortion,
shall not respond to signals from the AMP INPUT connector.

shall not affect RCA inputs. Priority Connector: 3-pin Phoenix-type con­nector shall allow Input 1 or Input 5 to mute other input signals by contact
closure. Input Routing Switch: DIP switches shall assign each input
signal to each output, two switches per input. Line Out Connector: One
3-pin balanced Phoenix-type connector per output channel, post master,
pre-VCA, with level control. Tone Generator Connector: 5-pin Phoenix­type connector; tones shall include Pre-Announce Chime, Bell, Alert Tone,
and Evacuate Tone; all tones shall be activated by contact closures on the
connector; internal jumpers shall be able to disable tones in an amplifi er
channel (excluding Pre-Announce Chime). Tone Level: One potentiometer
per output channel shall set the volume of the tones; tone level shall not
be affected by output volume controls or VCAs. The Pre-Announce Chime
shall be mixed with Channel-1 signals, so its level shall be affected by
the master volume control and VCAs. Input Connectors shall include a
Mic/Line Connector of 3-pin Phoenix-type, balanced, one per input chan­nel, and a dual RCA Input Connector for stereo music signals, unbalanced,
summed together, two connectors per input channel. Mic/line Switch:
Selects mic-level or line-level signals, one switch for each balanced input.
Link In/Out Switch: Slide switch, one per channel. With the Link Switch
IN, any signal applied to the Amp Input connector shall be mixed with the
input signal(s). With the Link Switch OUT, only the signal from the Amp
Input Connector shall appear at the amplifi er output.

Miscellaneous

Cooling shall be by convection. Included protection mechanisms shall
be current limiting, over-temperature thermal cutout, and DC-fault load
protection.

Included accessories shall be a power cord, detachable rack ears, screws
for rack ears, non-touch cover for output connectors, Phoenix-type con­nectors, and spade lugs. Optional accessories shall be a 1-VCAP remote
volume control for one channel, and a 4-VCAP remote volume control for
four channels.

The dimensions of the mixer-amplifi er shall allow for 19 inch (48.3 cm)
EIA standard (RS-310-B) rack mounting. The mixer-amplifi er shall be 3.5
inches (8.9 cm) tall, and 12.2 inches (31 cm) deep behind the rack-mount­ing surface (not including the non-touch cover).

The mixer-amplifi er shall weigh 25.3 lb (11.5 kg).
The mixer-amplifi er shall be designated the Crown 280MA.

Rear Panel Controls and Connectors

Rear panel controls and connectors shall include the following:
Reset Switch: Resets the circuit breaker that protects the power supply;

220/230/240V units shall have a fuse instead. AC Power Inlet: Detachable
IEC. Auxiliary Power Input: 2-position terminal strip for 24 VDC(±10%)
backup power; accepts up to 14 AWG terminal forks. Amplifi er Outputs
Connectors: One per channel, 4-position terminal strip with Com, 4 ohms,
70V and 100V terminals; accepts up to 14 AWG terminal forks, non-touch
cover included. Output VCA Connector: 4-pin Phoenix-type connector for
two VCA control lines of +10 VDC and ground; compatible with Crown
1-VCAP and 4-VCAP modules. Amp Confi g Switch: A DIP switch with
two functions which shall be 1. Assign an input as the priority input for
each output, thereby temporarily muting the remaining inputs; muting is
activated by contact closure. 2. Global enable switch for phantom power,

Crown International
1718 W. Mishawaka Rd.
Elkhart, IN 46517-9439
TEL: [phone]
FAX: [phone]FAX
www.crownaudio.com

Specifi cations subject to change without prior notice. Latest
information available at www.crownaudio.com.
Crown and Crown Audio are registered trademarks of
Crown International.
Printed in U.S.A.

© 2004 Crown Audio

12/04 138058-1

®

, Inc.