Designed for commercial and industrial use, the JBL CSMA 240 Mixer Amplifier for Commercial Usefrom JBL CSMA 240 Mixer Amplifier for Commercial Useis a mixer/amplifier with eight mixer-channel inputs and two output channels. It's capable of reaching 40W of peak power with 5W 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.

For Commercial and Industrial Use    40W into 8 or 4 Ohm Loads    5W Per Channel    8 Input Channels, 2 Output Channel    Usable with 70 & 100V Systems    Euroblock Mic/Line & RCA Inputs    Hi-Z & 27V Phantom Power Switches    Sleep Mode & 2 Auxiliary Outputs    Voice Activated Ducking & Priority Mute

8 inputs with 2 outputs of 40W of power.

Independent Bass and Treble controls for each output channel.
Input level and output volume controls.

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 (27 V) can be applied to all mic inputs by turning on Phantom Power within the dip switches.

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.

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 can be implemented using a CSR-V controller connected via an Ethernet cable to the RJ45 connector on the back panel.

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.

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.

Crown's DriveCore technology
HARMAN's GreenEdge environmental standards

Lead-free RoHS standards, utilizing recycled metals, and using an energy-saving powder coat process
Energy Star certified

Related Questions and Answers

Q: 1. How can I turn off the amplifier's sleep mode?

A: We are having BIG problems with the Sleep Mode. Even when there is signal, the unit is going in to sleep mode. We stood in front of a group of 15 at a church yesterday, all of them angry that we don't have a solution for this. Most times the unit does not come back on with signal, we have to power cycle, which causes a significant pop in the speakers.

Q: 2. HI, Is it possible to power my 200 watts speaker using Rane MA3?

A: This amp is 40-watts per channel, so it would not power 200 watt speakers. I would suggest a 200 watt amp, such as the ART SLA-2 - 2-Channel Rackmount Power Amplifier (200W Per Channel at 8 Ohms), BH #ARSLA2.

Q: 3. The amp is listed as 120 watts and there are two output channels. So, the amp is 120 watts per channel, correct? In other words, in a 70v application with two separate chains of speakers, each chain would have 120 watts available?

A: This amp is 120 watts per channel. In a 70v setup, each amp is putting out 120 watts.

Q: 4. Is it possible to output low impedance on channel one and high impedance on channel two simultaneously?

A: When in stereo mode, the QSC ISA300Ti Commercial Power Amplifier with 70V Transformer operates both outputs independently, so you could use one channel for 8Ohm and the other channel for 70V.

Q: 5. When an input is set to line does it transmit phantom power? If I use phantom power because I need it for a microphone input will it damage the Denon DN-300ZB that is also plugged into two of the input channels but set to line mode.

A: No, engaging phantom power for microphone input connections on the JBL CSM 28 Eight Inputs/Two Outputs Commercial Series Mixer would not affect a connection from a line level source such as the Denon DN-300ZB Media Player. It should be noted that the phantom power offered from this amplifier is 27VDC as opposed to the more common 48V.

Q: 6. How many speakers can this support? I have 5 JBL 25t speakers and want to make sure it can support all 5 or if I need to look at a different model.

A: Yes, depending on how you wire the system.

Q: 7. Can I use bluetooth with this kit?

A: I know that this question and previous answer is a couple of years old, but technically the answer is not accurate. You can connect a Bluetooth receiver that has an RCA output to this system to make it Bluetooth capable.

Q: 8. Does this include the rack brackets with purchase?

A: Yes. The rack mounting kit is included.

Q: 9. Is this an original version of the amplifier with the fan speed control? The product image silkscreen seems to indicate this is NOS.

A: No, this is the current version of the Rane MA 3 Three-Channel Power Amplifier which does not offer control of the fan speed. The earlier version did have a two-way switch that allowed you to run the fan at normal or fast speed. According to Rane, it was seldom necessary, if ever, to run the fan at the fast speed, except perhaps in very hot environments when used for heavily compressed music into a demanding load. The downside of running the fan at the fast speed was noise. For that reason the current version does not include fan speed control and provides thermal management with a sealed heat-tunnel design incorporating low velocity forced-air and large aperture openings. This design minimizes the noise usually associated with forced air cooling and eliminates the need for an air filter. Forced air-cooling allows the amplifier to operate reliably in harsh environments and avoid the buildup of heat in unventilated racks.

Q: 10. Will this amp work with a JBL 25t?

A: Yes it should power them just fine.