Data Sheet-6
MA 4
MULTICHANNEL AMPLIFIER
Power-Factor-Correction (PFC)
Near perfect Power-Factor with ⅓ the peak current and ½ the
average current (green) compared to non power-factor-corrected
supply with conduction of 3 ms (black). The response is mea-
sured at 100 watts.
Architectural Specifications
The unit shall be a four channel amplifier. It shall deliver 100
watts of power per channel into a 4 to 8 ohm load. The ampli-
fier shall incorporate load sensing with normal operation in the
range of 2 to 16 ohms. Front panel indicators shall alert presence
of a channel load outside of this range.
The amplifier shall have balanced inputs with Euroblock
connectors and Euroblock output connectors capable of accept-
ing 12 gauge wire. Sensitivity controls with a range of +22 to +4
dBu shall be provided for each input on the rear panel by means
of screwdriver adjustment. Load sensitive headroom meters shall
provide indication of 3, 6, 12 and 24 dB of remaining headroom.
Euroblock connectors shall be provided as a means of con-
necting remote DC level potentiometers or switches to attenuate
the input level of each channel.
Automatic redundancy switching shall be provided in the
event of a fault of any amplifier channel. Euroblock connectors
shall provide a means of connecting additional amplifier outputs
for automatic backup purposes. Each channel shall have master
or slave operation determined by a rear panel dipswitch. Master
channels shall write fault flag status, and Slave channels shall
read fault flag status.
A rear panel dipswitch shall provide a selection of 20, 40, 60
or 80 Hz highpass 2
nd
-order Butterworth filters. Load sensitive
limiter circuits shall prevent clipping and the associated loss of
speech intelligibility. A front panel LED shall indicate limiter
activity within each channel.
Built-in compressors shall be provided with a 10 dB thresh-
old. A rear panel dipswitch shall activate or deactive the com-
pressors. A front panel LED shall indicate compressor activity
within each channel.
Built-in expanders shall be provided with a -70 dBFS thresh-
old. A rear panel dipswitch shall activate or deactive the expand-
ers. A front panel LED shall indicate expander activity within
each channel.
Euroblock connectors on the rear panel shall provide a means
of transmitting or receiving fault flag information to other
amplifiers or indicators with an active 5 volt drive. A front panel
LED shall indicate a fault flag condition within each channel.
Thermal management shall employ forced air cooling, allow-
ing the amplifiers to operate reliable in ventilated racks at 40°C
ambient temperature. The fan speed air flow shall be controlled
by temperature. Intake shall be on the left side of the chassis and
exhaust on the right side, incorporating low velocity air flow to
minimize noise within a rack cabinet.
The universal internal switch-mode power supply shall
operate from 100 to 240 VAC, 50 or 60 Hz. The power supply
design shall provide power-factor-correction with very low inrush
current and overvoltage protection. An IEC connector and IEC
cord shall be utilized. A front panel mounted power switch shall
be provided.
The unit shall be a Rane Corporation Model MA 4.
Compressor Response
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Attack: 1.5 seconds
Release: 3 dB per second
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B
Input dBu
