JBL CSMA-280 Overview
Designed for commercial and industrial use, the CSMA 280 Commercial Series Mixer/Amplifier from JBL is a mixer/amplifier with eight mixer-channel inputs and two output channels. It's capable of reaching 80W of peak power with 10W per channel. The unit's front panel sports volume controls for each channel, as well as two master volume adjustment knobs, two sets of bass and treble controls, and a power switch. The volume controls are illuminated so they can be seen and operated in darkened environments.
The amplifier, capable of driving both eight and four Ohm loads, can be used with 70V and 100V distributed audio systems without the need for a separate transformer. On its back panel you'll find euroblock connections for mic/line inputs, as well as unbalanced RCA inputs, speaker connections, dip switches for input routing, and more. The unit is also equipped with two RJ45 connectors for use with JBL CSR-V in-wall volume controls (available separately).
This Commercial Series mixer/amplifier boasts such features as voice activating ducking (useful for paging over background music), priority muting for channels one and five, and a sleep mode which automatically powers down the unit when no audible signal has been received for longer than 30 minutes. Also, with two auxiliary outputs, you may connect to an additional amplifier, though the master volume and tone controls will have no bearing on the resulting signal.
Channel Modes
8 inputs with 2 outputs of 80W of power.
Controls
Independent Bass and Treble controls for each output channel.
Input level and output volume controls.
Hi-Z Switch
The Hi-Z switch will switch in the built-in output transformer allowing the unit to drive 70V or 100V speaker systems directly when connected to the appropriate output terminals.
Phantom Power
Phantom power (27 V) can be applied to all mic inputs by turning on Phantom Power within the dip switches.
VOX Function
Voice activated ducking is available on input channel 1 and channel 5. The audio input level required to activate ducking is set using the trim pot on the rear panel. Adjusting in the counter-clockwise direction will reduce that level, while the full clockwise setting will disable the VOX function.
Priority Muting
Channels one and five may be used as priority channels, muting all other channels when pins 4 and 5 are shorted using a switch closure. If the amplifier has entered sleep mode due to inactivity, invoking priority will also bring the unit out of sleep and ready for transmitting an announcement.
Remote Volume Control
Remote volume control can be implemented using a CSR-V controller connected via an Ethernet cable to the RJ45 connector on the back panel.
Sleep Mode
This unit is designed to go into sleep mode after approximately 30 minutes operating with no signal at any of the inputs. Return of signal (-40 dBu or 7.75mVRMS) to any input will wake the unit. Also, a switch closure across the priority input pins will return the unit to normal operating mode.
AUX output
An auxiliary output that you may connect to additional amplifiers is available. The audio signal is the mix of the input channels. Note that the master volume control and tone controls will have no effect on the aux output signal.
Manufacturing
Crown's DriveCore technology
HARMAN's GreenEdge environmental standards
JBL CSMA-280 Specs
Maximum Output Power 80 W per channel into 4 Ohms or 8 Ohms, 1 kHz, ≤ 0.5% THD
Insertion Loss 1 dB maximum for 70 and 100 V outputs
Continuous Power 10 W per channel
Line Output Level 5.0 V RMS into 10 kOhms
Input Sensitivity To obtain full rated power at 8 Ohms (or 5 VRMS to line output)
Mic Input: 3 mV RMS
Line Input: 775 mV RMS
RCA Input: 300 mV RMS
Number of Channels Input: 8
Output: 2
Frequency Response Measured at 2.83 V RMS into rated load impedance at any output
4/8 Ohms Output: 20 Hz - 20 kHz, ±2 dB
70 V/100 V Outputs: 80 Hz - 15 kHz ±2 dB
Line Out: 20 Hz - 20 kHz, ±1 dB
Total Harmonic Distortion (THD) Measured at 2.83 V RMS into rated load impedance at any output
Power Amplifier Output: <0.5%, 20 Hz to 20 kHz
Line Output: 0.05% typical
Signal to Noise Ratio > 90 dB
Nominal Input Impedance Mic: 400 Ohms
Line: 20 kOhms (balanced)
RCA: 50 kOhms
Minimum Load Impedance Low Impedance Output: 4 Ohms
70 V Output: 60 Ohms
100 V Output: 120 Ohms
Crosstalk -70 dB @ 1 kHz
Controls Front Panel:
8 x Input level rotary knobs
2 x Output volume-attenuating knobs
1 x Power switch
2 x Bass potentiometers
2 x Treble potentiometers
Rear Panel:
2 x Input-routing dip switches (including phantom and Hi-Z switches)
8 x Mic/Line selector switch
2 x Vox adjustment switches
Indicators Front Panel:
8 x Input signal presence ring, green
2 x Output volume ring, green
1 x Power switch ring, green/blue
Connectors Rear Panel:
1 x IEC power input
2 x Aux out connection points
6 x 3-pin euroblock connectors
2 x 5-pin euroblock connectors
6 x Dual RCA input connectors
2 x RJ45, remote volume
Operating Temperature / Humidity 32 to 95°F / 0 to 35°C, 95% RH (non-condensing)
Storage Temperature -4 to 185°F / -20 to 85°C
Phantom Power 27 VDC
AC Input 100-240 VAC, 50/60 Hz
Dimensions (W x D x H) 17.2 x 11.9 x 1.7" / 436.9 x 302.3 x 43.2 mm
Weight Approximately 11.9 lb / 5.4 kg
Packaging Info
Package Weight 16.0 lb
Box Dimensions (LxWxH) 20.5 x 16.3 x 5.2"