For bridged-mono operation, turn the amplifier off and move the Stereo/Mono switch to the BRIDGED MONO
position. Connect the input signal to CH2 input (CH1 input becomes disabled). Connect the speaker(s) to the
two (+) speaker terminals. The CH2 red post is the hot (non-inverting) side, and the CH1 red post is the low
(inverting) side (see Figure 6).
When connected in this way, each channel “sees” one-half the impedance of the speaker that is connected between
them. If an 8 ohm speaker is used, each channel will see a 4 ohm load. Therefore it is not recommended that anything
lower than 8 ohms be connected in this mode of operation. Use Parallel Mono operation for lower impedances.
Note: Be sure to set both of the input level controls to the exact same setting for equal power distribution per channel.
Note: In bridged mono operation, the output connections are actually a balanced output configuration. This means
that neither output terminal may be grounded (both have voltage present).

Caution: Extreme care must be taken if using 1/4˝ phone plugs as speaker connectors with the amp in bridged-
mono mode. The reason for this is when connected to a bridged-mono output, the shell of the plug is “hot” and
could cause a nasty surprise if it comes in contact with something or someone that is grounded. If you must
use phone plugs at the speaker connection, at least insulate the shell of the plug with shrink sleeving.

Parallel Mono

Parallel-mono operation is useful when you are running sustained high levels into a single load, or when
driving a low impedance load. To configure the amplifier for parallel-mono operation, contact Carver
Professional Technical Service Department for Field Application Bulletin pm125-1. It contains detailed
instructions describing the simple procedure for modifying both the pm125 and pm420 power amplifiers for
parallel-mono operation.

Clipping Eliminator

This circuit prevents the input signal from exceeding the point where it would drive the amplifier into hard
clipping. It has no effect on the signal until it reaches the point where clipping would occur. The larger the input
signal the more the signal is reduced to keep the output just below clipping. The Clipping Eliminator circuitry
is inactive when the unit is shipped from the factory, but can be activated by installing jumpers in sockets JP9
and JP6 (see instructions on page 13).
Note: If the Input Level control(s) are turned down far enough, a sufficiently large input signal can drive the
input differential amplifier into clipping. The Clipping Eliminator circuit cannot remedy this kind of clipping.
Likewise, it has no effect on clipping that occurs prior to the amplifier inputs (at the mixer or equalizer stage,
for example).