The MA 3 is a three-channel amplifier designed to operate reliably in commercial environments. The MA 3 was specifically designed for use in:
The MA 3 uses a conventional linear power supply with a toroidal transformer. This configuration minimizes the emissions associated with switching supplies and noisier transformer designs. The power supply features independent secondary supplies for each channel, minimizing load regulation interaction and crosstalk.
Thermal management is accomplished 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 associated with passive convection cooling.
The combination of a solid, conservative power supply and forced-air cooling allows the MA 3 to simultaneously deliver 40 watts of continuous average power into 8Ω and 60 watts into 4Ω.
SPiKe®* dynamic protection circuitry completely safeguards each channel against over-voltage, under-voltage, overloads, transients from inductive loads, thermal runaway and instantaneous temperature peaks. Biasing is not allowed to occur when an under-voltage condition exists, reducing turn on and turn off transients.
Fast-response limiters allow the MA 3 to tolerate up to 20 dB of overdrive into 8 and 4Ω loads while holding THD below 1%. This means no loss of speech intelligibility or harsh clipping. This feature greatly increases the dynamic range of the system without external limiters.
Peak-responding, load-adaptive meters accurately indicate the remaining headroom. The meters are helpful in setting system levels and indicating signal compression.
Balanced inputs with Euroblock connectors are provided. Euroblock output connectors accept up to 12 gauge wire. Rear panel Level controls allow amplifier sensitivity adjustment. Internally selectable 80 Hz highpass filters offer protection against over excursion of small bookshelf speakers and saturation of distribution transformers at low frequencies.
The MA 3 Amplifier drives all three channels at the continuous average rated power, indefinitely. It is specifically designed to operate in demanding commercial applications. Very low emissions allow the amplifier to operate in close proximity to signal processing equipment without causing excessive interference. The CP 52S, CP 64S and DA 26S may all operate next to the MA 3 in a rack. The high efficiency “heat tunnel” design allows the amplifier to process severely compressed signals reliably even when installed in a rack with elevated ambient temperatures. Forced-air cooling keeps heat away from other equipment.
The MA 3 is designed to deliver foreground music, background music and paging signals to three different Zones without annoying crosstalk. A quiet office, for example, with a paging signal only, will not hear foreground music playing in the lounge. The high capacity linear power supply incorporates three independent secondary supplies with independent bridge rectifiers and filters. The result is exceptionally good crosstalk figures even with multiple channels driving full power into 4Ω loads.
The MA 3 is designed to operate without interruption of signal with as little as 85 VAC available (120 VAC unit). Even if the Amplifier is operating at full power, the signal will not breakup as the AC line voltage drops to 85 VAC. If the AC line drops lower than 85 VAC the signal mutes without “spikes.” Once AC power is restored, the signal restarts quickly without “spikes” or signal breakup.
The power amplifiers in the MA 3 are protected with National Semiconductors’ proprietary SPiKe* protection circuitry. SPiKe protection offers a level of protection not available in conventional amplifiers. It has the ability to instantaneously monitor the temperature of the power device die, yielding a level of reliability not achievable with discrete designs.
The high-performance limiter used in the MA 3 means all the available power can be delivered to the load and not simply held in reserve to avoid overload. There is no need to buy up to four times the required power just to prevent occasional system overload. The MA 3 can compress a signal with 9 dB of dynamic power range down to a signal with 3 dB of dynamic power without loss of speech intelligibility or excessive distortion. With typical amplifiers, when 40 watts is needed to achieve a required average SPL of 80 dB, the contractor must buy an amplifier rated at no less than 160 watts just to maintain 6 dB of headroom. The figure below illustrates the performance of the MA 3 limiter.
*Spike is a registered trademark of National Semiconductor Corporation.
SPiKe is an acronym for Self Peak Instantaneous (Ke) protection circuitry.
The MT 6 is simply a 2U rack panel that can mount up to six distribution transformers for Rane MA 3 amplifiers.
Constant-voltage transformers are purchased individually:
Both transformers rated at 40 watts, 50 Hz to 15k Hz ±1 dB, with 0.5 dB insertion loss. The transformer wires have insulated female tabs. To accomodate different installation preferences, each transformer includes:
The MA 3 had a design change in February 2007 affecting whether the transformers are mounted internally or externally. For MA 3 amplifiers manufactured after February 2007, use the MT 6 rack panel with up to six transformers installed. For MA 3 amplifiers manufactured before February 2007, transformers may be mounted internally. If you aren't sure, the old MA 3 has six transformer mounting holes above the input jacks.
Each unit is shipped with a booklet containing the Manual with Safety and Compliance information, all the Data Sheets, the Schematic, the RaneNote "Sound System Interconnection," the RaneNote "Constant-Voltage Audio Distribution Systems," Declaration of Conformity, and Rane's 2+ Year Warranty information.
Can I feed all channels the same signal just by connecting to one of the channels?
No. You can use jumpers to connect all input channel connectors (plus and minus required).
My system seems a bit noisy running through the amp. Is there something wrong with the equipment?
Not likely. The most common misconception is that amplifiers must be turned up all the way to achieve maximum output. This is simply not the case. Most amplifiers will reach full output (and clip accordingly) with sensitivity controls set between 12 and 2 o'clock when fed a + 4 dBu signal. Try turning down your amp(s) and verifying the clipping point. This can make a drastic improvement in reduction of noise.
Can I run the MA 3 below 4 ohms load?
Probably. It will not be damaged but you will obtain much less power output. The MA 3 will current limit as necessary. Its fan must be set to high speed.
If the above options don't answer your question, or it's urgent...
Phone 425-355-6000, 8:30 AM to 5 PM PST, Monday through Friday.
If it's less urgent, you can email the factory.
For local service within the USA, find a service center.