www.cleveracoustics.co.uk
MA 4120 480W Mixer Amplifier
User Manual
8
Operating instructions
27. Input sensitivity and phantom power control:
Channels 1, 2, 3 & 4 each feature switchable inputs for use with MIC/MIC+Phantom/Line signals. The
MIC positition is designed to accept a balanced, low level signal from a standard dynamic microphone
(5mV/1kΩ). The PHANTOM position is designed to provide 15V phantom power across XLR pins 2 & 3
for use with condenser microphones. The LINE position is for use with line level sources such as radio
microphone receivers, CD players and FM tuners (100mV/10kΩ), the signal may be inputted using
either the balanced XLR or balanced TRS 6.35mm (¼”) jack.
28. Balanced line level zone outputs:
The MA 4120 MKII features four, independent zone outputs each utilising barrier strip terminals for the
balanced audio output (1.7V). The line level outputs may be used to feed signal to external amplification
where additional amplification is required. If the amplifier connected only requires an unbalanced signal,
the output contacts “+” and “G” should be used.
29. Power amplifier outputs:
Each of the four output zones on the MA 4120 MKII features both low impedance and constant voltage
loudspeaker outputs. Each output zone may be used to output into either low impedance (4-8Ω) or
constant voltage (25V, 70V, 100V). Do not use more than one pair of output terminals on any one
output zone. Care should be taken when connecting to the outputs to ensure the load impedance is
above the minimum load specified for the output.
Power on/off procedure:
Prior to making any connection to the mains power or audio inputs/outputs, turn all level controls
counter clockwise to the
“0”
position and all tone (equaliser) controls to the mid (zero) point. Deselect
all monitor and zone selection controls.
Switch on the zone mixer and any audio sources (MP3 players, CD players, Microphones etc) before
powering the systems amplifier ON. The last product to be switched on should be the power/slave
amplifiers to prevent any unwanted noise or potential damage to speakers or amplifiers. If you wish
to power off the system, turn the amplifier’s master volume control counter clockwise to the
“0”
position before switching the amplifier OFF before any audio sources are switched off. By following this
procedure it will prevent acoustic shocks to the speakers or potential damage to system components.
After connecting all audio sources and powering on the system, adjust the level of each audio input,
select the zone routing in order to achieve the desired “mix” for each zone. Care should be taken
to when adjusting microphone input volumes and the master volume, adjust both of these in small
increment’s to avoid feedback (howl around). The goal is to achieve a clear balance between music and
voice ensuring announcements can be clearly heard.
