Directed Audio 750d 1500d Combining Amplifiers, Parallel Synced Gain, External Synced Bridged

COMBINING AMPLIFIERS

The Viper 750d/1500d subwoofer amplifiers have the capability of connecting two or more amplifiers of the same power rating together in a master/slave combination for increased power with accurate level matching. They are the Parallel Synced Gain and External Synced Bridged combinations.

WARNING: DO NOT attempt to combine amplifiers of different power ratings. These amplifier combinations work correctly only if the Master and Slave amplifiers are identical models.

Parallel Synced Gain

In this master/slave combination the master amplifier pre-amp controls remain active and the slave amplifier pre-amp is bypassed. This allows the master ampli- fier to control gain, filter, and sub-level on both amplifiers.

This combination allows the amplifiers to drive their own separate subwoofer(s) while being synced together via an in- phase audio pre-amp signal from the master amplifier. Wiring connections to the amplifier subwoofer outputs in this combination should be standard in-phase configurations, creating a parallel speaker connection. (Refer to Parallel Synced Gain section of this guide for amplifier and speaker connection diagrams.)

NOTE: One master amplifier can control up to three slave

amplifiers in this combination. Multiple identical master/slave combinations can be added to any given system.

External Synced Bridged

In this master/slave combination the master amplifier pre-amp controls remain active and the slave amplifier pre-amp is bypassed. This allows the master amplifier to control gain, filter, and sub-level on both amplifiers. This combination allows the amplifiers to drive common subwoofer loads while being synced together via an out-of-phase audio pre-amp signal from the master amplifier. In this subwoofer wiring configuration the master amplifier sends the positive signal to the subwoofer while the slave amplifier sends the negative signal, making an externally bridged speaker connection. (Refer to External Synced Bridged section of this guide for amplifier and speaker connection diagrams.)

NOTE:	Amplifiers in this combination can only be connected
	in matched pairs. Multiple matched pairs may be
	added to drive separate subwoofer loads in a given
	system.

Combined Amplifiers Gain and Filter Settings

Set the Subsonic, EQ, and other filter settings on the master amplifier to the positions that achieve the best sound quality. Adjustment guidelines are discussed in the Crossover and Gain Adjustment section of this guide.

12 © 2003 Directed Electronics, Inc