Bridge-Mono Operation; Bridge-Mono Wiring - Crown Macro-Tech MA-1200 Reference Manual

3.3.2 Bridge-Mono Operation

Bridge-Mono mode is intended for driving loads with a
total impedance of 4 ohms or more (If the load is less
than 4 ohms, see Section 3.3.3). Installing the amplifier
in Bridge-Mono mode is very different from the other
modes and requires special attention.
To put the amplifier in Bridge-Mono mode, turn the am-
plifier off and slide the stereo/mono switch to the right
(as you face the back of the amplifier). Both outputs
receive the signal from Channel 1 with the output of
Channel 2 inverted so it can be bridged with the Chan-
nel 1 output. DO NOT USE THE CHANNEL 2 INPUT or
the signal level and quality may be greatly degraded.
Keep the Channel 2 level control turned down com-
pletely (counterclockwise).
Note: The input jack and level control of Channel 2 are
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not defeated in Bridge-Mono mode. Any signal fed into
Channel 2 will work against and add to or distort the
signal in Channel 1.
Connect the load across the Channel 1 and 2 red bind-
ing posts with the positive lead from the load attaching
to the red post of Channel 1 and the negative lead of
the load attaching to the red post of Channel 2 as shown
in Figure 3.5. THE TWO BLACK BINDING POSTS ARE
NOT USED AND SHOULD NOT BE SHORTED. The
load must be balanced (neither side shorted to
ground).
CAUTION: Be certain all equipment (meters,
switches, etc.) connected to the mono output is bal-
anced. To prevent oscillations, both sides of the line
must be isolated from the input grounds.
Fig. 3.5 Bridge-Mono Wiring
Macro-Tech 600/1200/2400 Power Amplifiers
Reference Manual