JBL MTC-CBT-70T Transformer
MTC-CBT-70T is a bolt-on transformer module to adapt CBT 70J-1 and CBT 70JE-1 (and CBT 70J-1/JE-1 arrays) for use on distributed loudspeaker lines. It allows long cable runs and multiple speakers to be driven from a single distributed system amplifier channel.

Transformer taps include 120W, 60W, and 30W for 70V and 100V distributed lines, plus 15W for 70V only.

Connections are made via customer-supplied cable to screwdown terminals inside the enclosure. Two gland nuts are provided - one for the cable into the enclosure from the amplifier and one for the cable from the enclosed terminal strip to the input terminal of the loudspeaker. The gland nuts form a water-tight seal when used with round jacketed cable with outside diameter between 4.0 mm (0.16 in) and 9.0 mm (0.36 in).

The tap selection is made via the terminal connection of the cable from the power amplifier to the appropriate terminals on the internal terminal strip.

Mounting holes are provided that fit via two 6 mm screws to any of the two side-by-side insert points on the back of the CBT 70J-1 or CBT 70JE-1 cabinet.

Note that MTC-CBT-70T extends 86 mm (3.4 in) from the back of the CBT cabinet.

Available in black or white (-WH).

• Gland Nuts Provide Water Tight Seal


• Bolts onto Back of CBT 70J-1 or 70JE-1 Speaker


• 120W, 60W, 30W for 70V or 100V (plus 15W for 70V)


• Adapts the CBT 70J-1 (and 70JE-1) for Use on Distributed Speaker Lines