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The Biamp CMA Series comprises commercial mixer/amplifiers designed for versatile audio applications, combining a 6-input mic/line mixer with amplification options of 30, 60, 120, or 350 Watts. These units are engineered for both direct and distributed speaker systems and come with a five-year warranty.
The CMA Series units integrate a mixer, power amplifier, and output transformer into a single chassis. They feature six input channels, with channels 1-5 offering electronically balanced microphone/line inputs and channel 1 specifically providing a transformer-balanced microphone/line/telephone input. Each input channel includes a rear panel trim control and a pad switch for signal level adjustment. Phantom power (+24 Volts DC) is selectable on each input channel to power condenser microphones. Input isolation transformers are optional for channels 2-6 on all models except the CMA350, which includes them as standard on channel 1.
The mixer section offers comprehensive control over audio signals. Automatic muting can be configured for selected non-priority channels, with muting levels adjustable to -10dB, -20dB, or -40dB. This automatic muting is triggered when a signal is present in a designated "priority" channel. Manual muting of selected channels is also available at the same attenuation levels, triggered by remote contact closures via rear panel terminals. A 'pre-announcement' chime tone with an adjustable level control can be activated by these manual mute triggers.
Output signal processing includes an integral output compressor with a rear panel threshold control to reduce peak levels and moderate volume differences. Tone control is provided by recessed treble and bass controls, which can be enabled or disabled via a front panel switch. A "loudness" filter can be engaged for tonal compensation with low-level music signals, and a "low-cut" filter (6dB/octave @ 120Hz) is available at the amplifier input, particularly recommended for 25/50/70/100 Volt speaker systems.
For system interconnections, the units offer two insert points for signal processing or remote control, two line-outs, and one stack-in. The Send/Return jack provides an insert point after Stacking In, Loudness, and Tone, but before the Compressor, Master Level, and Low Cut. The Stack-In terminals provide a balanced line-level input to the mix bus for input expansion.
Front panel controls include individual level controls for each of the six input channels and a master level control for overall system volume adjustment. Screwdriver-adjustable bass and treble controls allow for fine-tuning of low and high frequencies. Front panel indicators provide visual feedback on the unit's status, including power (green LED), fault conditions (red LED), signal presence (yellow LED), and peak levels (red LED).
Rear panel barrier strip terminals provide secure connections for all inputs and outputs. The output terminals support various speaker loads (4Ω, 8Ω, 25V, 50V, 70V, or 100V), with a switch to select between direct or transformer-coupled output. Remote control of the master level is possible via rear panel terminals, allowing for adjustment from up to 2000 feet away using a 5k~50kΩ linear taper potentiometer or switch.
DIP switches on the rear panel allow for assignment of specific functions to individual channels, such as phantom power, auto mute, manual mute, and priority status. The Trim control on each input channel adjusts the input gain to prevent distortion. The Line/Mic switch selects the appropriate impedance and gain for microphone or line-level signals, with a dedicated Tel switch for Channel 1 to accommodate 600 ohm telephone system audio ports.
The CMA Series is designed for ease of integration into various commercial and industrial paging systems, as well as house of worship sound reinforcement systems. Examples include multi-floor office/hospital paging systems and retail store paging systems, demonstrating flexible routing, muting, and level control capabilities.
The CMA Series units are designed with a removable front panel security cover, which provides access only to the power switch when installed. To remove the cover, two captive screws can be loosened with a 3mm hex wrench. The units also feature removable rack-handles, secured by two screws on each side, allowing for flexible installation options.
For AC power, the units accept a 3-prong AC power cord, with a chassis ground post provided for system grounding. The AC fuse is located in the lower portion of the AC Power Cord receptacle and can be replaced by qualified personnel. The CMA350 model includes a power selector switch on the rear panel to select between 115 Volt or 230 Volt AC operation, while other models have this switch recessed on the underside of the chassis.
Fault indicators on the front panel alert users to conditions such as overheating, DC offset voltage, or low-voltage power failure. While some faults may self-correct after the unit is turned off, persistent fault indications require contacting a local Biamp Systems dealer for service. The device is CE marked, UL, and C-UL (UL Canada) listed, ensuring compliance with relevant safety and electromagnetic compatibility standards. Maintenance and modifications, particularly those involving internal wiring or optional equipment, are intended for qualified installation and service personnel only. The output terminal cover must be installed when the device is energized to mitigate the risk of hazardous energy.
General| Mounting | Rack-Mountable |
|---|---|
| Cooling | Convection |
| Power | 100-240V AC, 50/60Hz |
| Frequency Response | 20 Hz to 20 kHz |
| Total Harmonic Distortion | < 0.1% |
| Damping Factor | > 200 |
| Protection | Thermal, short-circuit |
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