Precision Power PPI4240 specs

All PPI amplifiers are capable of being bridged into a 4-Ohm mono output without switches or bridging modules. This in turn allows you to run Full range or component speakers and a subwoofer off one PPI amplifier. (using passive crossovers)

You can achieve this mono channel by using the Left positive (+) speaker connection and Right negative (-) speaker connection. You can bridge channels 3 and 4, on your PPI four channel amplifiers, in the same way. (Refer to the end panel drawing on page 8.)

Your new PPI amplifier offers you the flexibility of mixed mono operation. This means you can operate each pair of channels in both stereo and mono mode at the same time. This is accomplished by using highpass filters (capacitors) on the higher frequency stereo channels, and a lowpass filter (coil) on the subwoofers. The frequencies of the chosen highpass and low- pass filters must not overlap (allow the mids and highs to play the same music as the subs) or the impedance the amplifier sees at those frequencies will be cut in half possibly causing it to go into protection.