Switching On - MC2 Audio MC450 Operating Instructions Manual

BRIDGED (MONO) OPERATION
Connect as follows : HOT
COLD
Leave both COLD connections open circuit, they are internally joined.
NOTE: The load impedances change when operating in the bridged mode. (See Load/Power section
below.)
LOAD/POWER SWITCH 2 ohm/4 ohm
In the 4 ohm position, the amplifier supply voltages are set up for loads of 4 ohms and above. Lower
impedance loads can be connected but the internal current limit circuit could cause clipping, and unless
the signal is very dynamic, the internal temperature rise will automatically reduce the supply voltages and
set the amplifier to the 2 ohm position. In the 2 ohm position, the supply voltages are reduced and the
level (overload) indicators and limiters are re-referenced accordingly.
When operating in bridged mode, the minimum impedances are doubled, i.e. for 4 ohm loads use
the 2 ohm position and for 8 ohm loads use the 4 ohm position. The minimum load in bridged mode
is 4 ohms.
OPERATION

SWITCHING ON

When the amplifier is switched on, the outputs will be muted and the controller will check for any faults.
It then goes through a power up routine and finally connects the speakers to the output stages and fades up
the signal to the level at which the amplifier was previously set.
PANEL CONTROLS AND INDICATORS
Level controls
These are continuous rotary encoders which provide fine adjustment (3 turns from min. to max.). When
adjusted, the level indicators change to level control position indicators and thus the height of the LED
column shows the level position. After a second or so the LED column changes back to monitor the signal
level. This function can be changed internally via the programming switches on the control PCB. (See the
Internal Configuration section.)
Mute Switches
These are self explanatory, and require one push to mute the signal and one to un-mute - toggle action.
The LEDs indicate their status and when "un-muting" the signal is ramped (faded) up.
Link Switch
This is also a toggle action switch, the LED above indicates its status. When ON, the two level controls
are linked together and either control will adjust both channels to the same level. The controls track very
accurately and operate as stereo attenuators. The limiters are also linked. When OFF, the level controls
and limiters operate separately.
Level Indicators
These are peak reading meters which show the signal headroom before clipping. The 0dB LED is set at
approximately 1/2dB below clipping. They are referenced to the supply voltages and automatically adjust
when the supply changes. When the level controls are adjusted, the level indicators change function and
show the level control position. They return to their normal function after the level has been set.
- Channel A Hot
- Channel B Hot
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