GTO-5EZ - JBL Car Audio Service Manual (repair manual). Page 6

The GTO-5EZ and GTO-3EZ amplifiers have multiple input connectors with routing switches that increase flexibility, so 
you can use these amps in a variety of audio system configurations.

The GTO amplifier routing switches let you determine which input connectors drive the amplifier’s various speaker 
outputs:

Front/Rear Routing switch:

• F: The front and rear speaker outputs are both fed by the Front Input connectors.

• F&R: The front speaker outputs are fed by the Front Input connectors; the rear speaker outputs are fed by the 

Rear Input connectors.

Sub Routing switch:

• F&R: The Sub speaker output is fed by the Front and Rear Input connectors. (For use with source units that do not 

have a dedicated subwoofer connector.)

• S: The Sub speaker output is fed only by the Sub Input connector. (For use with source units that have a 

dedicated subwoofer connector.) 

Sub Routing switch:

• F: The Sub speaker output is fed by the Front Input connectors. (For use with source units that do not have a 

dedicated subwoofer connector.)

• S: The Sub speaker output is fed only by the Sub Input connector. (For use with source units that have a 

dedicated subwoofer connector.)

Use RCA audio cables to connect source units with preamp-level outputs to the amplifier; use the supplied bare wire-
to-RCA adapters to connect to source units that don’t have RCA output connectors.

Use a small Phillips screwdriver to loosen the adapter’s set screws and insert the speaker wires into the holes on the 
back of the adapter. Tighten the set screws to secure the wires. 

Always connect the (+) speaker wire to the (+) terminal on the adapter and the (–) speaker wire to the (–) terminal on 
the speaker.

IMPORTANT: Make sure the (+) and (–) bare wires do not touch each other. Touching wires can cause a short circuit 
that can damage the source unit or the amplifier.

When you’re finished, plug the adapter into the appropriate input connector on the amplifier. 

• For bridged operation: Connect to either the left or right input connectors if you wish to feed the amplifier a mono 

signal (such as the center channel from a processor that outputs a center channel signal), or connect to both 
inputs if you want the amplifier to create a mono signal for a single speaker.

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