Crown 28M User Manual
28M
COMMERCIAL AUDIO SERIES
Architectural & Engineering Specifi cations
28M
The Crown® 28M shall be a mixer for commercial and industrial audio. It
has 8 inputs and 2 output channels for two-zone systems.
Specifi cations
The 28M shall have the following specifi cations:
Frequency Response (at line out, 20 Hz to 20 kHz): +/– 1 dB. Signal to
Noise Ratio (master volume at minimum): 100 dB. THD: 0.05% typical
with 800 mV balanced input, 1V output. 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 (all controls at "10"): –70dB at
1kHz. Line Output Level (nominal): 1.2 V 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. The power switch shall not affect
the 24V DC auxiliary power input. 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 –24 dBu
(line) or –70 dBu (mic). Output Signal Presence Indicator: Green LED, one
for each input channel, illuminates when input signal exceeds 100 mV. Clip
Indicators: Red LED, one per output channel, illuminates at threshold of
audible distortion.
Rear Panel Controls and Connectors
Rear panel controls and connectors shall include the following:
Fuse: protects the power supply. 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. Mixer 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, shall not affect RCA inputs. Priority Connector: 3-pin Phoenixtype 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; level controlled by master volume control. 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 miclevel or line-level signals, one switch for each balanced input.
Miscellaneous
Included accessories shall be a power cord, detachable rack ears, Phoenixtype connectors, and spade lugs.
The dimensions of the mixer shall allow for 19 inch (48.3 cm) EIA standard
(RS-310-B) rack mounting. The mixer shall be 1.7 inches (4.3 cm) high,
and 14 inches (35.6 cm) deep behind the rack-mounting surface.
The mixer shall weigh 8.7 lb (3.9 kg).
The mixer shall be designated the Crown 28M.
Crown International
1718 W. Mishawaka Rd.
Elkhart, IN 46517-9439
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 and Crown Audio are registered trademarks of
Crown International.
Printed in U.S.A.
© 2007 Crown Audio
®
, Inc. 12/07 138171-1D
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