Australian Monitor KA1500 - Manual (Page 15)

Bridge Mode 15
5. Bridge Mode
The term BRIDGE is used when two independent
amplifier channels are used to drive the same load.
The load is in series (a bridge) between the two
amplifier channels.
Channel A is used as the "dominant" channel and its
output is in phase with the input signal, and channel
B has its phase reversed so it is exactly 180
0 out of
phase with the input signal.
As two amplifiers with a phase difference of 180 0 are
now driving the load you will now have double the
voltage into the load. This means you will now have
four times the power into that load. The output can
now be considered as an active balanced output.
A common use of an amplifier in BRIDGE mode is for
driving 70 volt & 100 volt distribution lines. In BRIDGE
mode, The
KA1500 KA1500 KA1500 KA1500 KA1500 can produce over 110 volts with
line impedances over 8 ohms.
Equally the units can be used in bridge mode to
provide the correct voltage/power requirements for
an applicable load.
As shown in Figure 6, there are three steps in setting
up your amplifier for running it in BRIDGE mode.
Whilst the amplifier is off,
1. Connect the signal source to the Channel-A female
input XLR. The Channel-A attenuator becomes
the level control for both channels.
2. Engage the “push to bridge” switch.
3. Connect your load between the red binding post
output terminals, where the positive side of the
load is connected to the channel A output (marked
BRIDGE+) and the negative side of the load goes
to the channel B output (marked BRIDGE
- ). There
are no further connections required.
You can also source the output from the Channel-A
SPEAKON output connector where Channel-A will
be on the pin marked 1+ and Channel-B will be on the
pin marked 2+.
NOTE: You should check after market manufactured
Speakon interconnecting speaker leads before
connecting them to your amplifier. Some leads are
manufactured for specific purposes, or specific use,
and may have pins shorted inside the connector. Any
speakon lead with shorted pins will obviously short
the output of your amplifier (either to ground, or
output to output - be careful).
Figure 6 Bridge Mode Speaker Connection