J+4

The J+4 takes unbalanced stereo sources and converts them to a balanced +4dB output that can run over long cable distances without losing signal. It combines active buffering with transformer isolation, which provides clean gain and removes noise caused by ground loops.

Several input connector types are provided so that different devices can be connected directly: stacked 1/4" jacks for DJ mixers and keyboards, RCA inputs for CD players, and a 3.5mm (1/8") TRS mini jack for computers, smartphones and tablets. A volume control sets the level sent on to the balanced outputs, which use XLR connectors.

Typical uses include boosting a CD player or laptop to line level, and bringing keyboards or older synthesizers with weak output up to a level that a mixer's line inputs can use. The unit comes with an external power supply, and rack adapters, pedalboard brackets and flange mounts are available as accessories.