III. BRIDGED SETUP
WARNING:
The 33.0 normally operates in stereo mode, providing a maximum output power of
330 watts Class AB (into an 8-ohm load) per channel. In bridged mode, both
channels act as one amplifier providing a maximum output power of 660 watts. For
extremely high-power multi-channel audio applications, multiple 33 amplifiers can
be used in place of one stereo amplifier.
To configure the amplifier for bridged mode operation you must enable the bridging
switches inside the amplifier. Use a 5/64” hex driver to remove the twelve screws from
the top of the amplifier and remove the top cover. The bridging switches are
mounted on a circuit board attached to the audio input jacks inside the amplifier.
The diagram below shows the circuit board. The red slide switches below the arrows
are the bridging switches. The arrows show the direction to set the switches to enable
bridging. Reverse the switch positions to enable normal stereo operation.
In bridged mode only one audio input is used. No other input should be connected,
and the bridged mode input must be a balanced signal connected to the XLR
receptacle labeled BRIDGED INPUT. Bridged mode will not operate correctly with an
input adapted from an unbalanced signal. Connecting the input signal to the
receptacle not labeled BRIDGED INPUT will cause no damage, but will cause the
speaker terminal polarities to reverse, with the terminal labeled positive becoming
ground and the terminal labeled ground becoming positive.
The amplifier’s speaker terminals are reconfigured in bridged mode. The left channel
positive terminal becomes the monaural negative terminal and the right channel
positive terminal becomes the monaural positive terminal.
See the next page for a diagram of a stereo amplifier configuration using two
bridged mode 33.0 amplifiers. Speaker terminals in the diagram are marked with
their bridged mode polarities.
Disconnect the amplifier's power cord from the AC supply and set the power switch
to OFF before adjusting the mode switch or connecting or disconnecting any
cables to avoid potential damage to your speakers and personal injury due to high
internal voltages.
DETAILED INSTALLATION
6
BRIDGED
STEREO
MODEL
SERIAL NUMBER
MODE
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