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Jack Connectors

Jack Plug & Panel Mounting Socket


2 or 3 pole connector mainly used for audio applications. Line and panel mounting sockets are available, the panel mounting version being available in many forms with different mounting and switch options. 3 pole versions are used for stereo or balanced mono. 3 sizes are available  - 2.5mm, 3.5mm and 6.35mm (¼"). Suitable for extra low voltage only. Note that due to the design, the poles are shorted together briefly as the plug is inserted, making them a poor choice for power supply connections.

Typical Applications

Audio - Microphones, Headphones, Mixers, Loudspeakers etc.

Extra Low Voltage power connections (<50V)

Other extra low voltage signal or power applications

Pin Assignments

Unbalanced Audio (Mono & Stereo):

Unbalanced Mono and Stereo connections

Balanced Audio (Mono):

Balanced Mono connections

This is a mono connection, 2 plugs will be required for stereo. To connect balanced to unbalanced bridge ring and sleeve or use 2 pole plug in 3 pole balanced socket.

DC Power:

Either polarity may be used, although normally the tip is positive and the sleeve is negative. However the poles will be shorted together momentarily as the plug is inserted into the socket. This makes jack connectors a bad choice for power connections, use barrel type connectors instead.

Identifying Connections in Plugs & Line Sockets:

The sleeve is connected to the long pin, the end of which forms the cable clamp. In audio applications the screen of the cable should be connected to this. Stereo connectors will have 2 smaller terminals, the tip and the ring. Often the tip terminal is coppered, but it's best to check with a continuity tester. Mono connectors may have one or two terminals - if there are two then connect them together.

Identifying Connections in Panel Sockets:

These vary and may have extra switched terminals, e.g. to mute loudspeakers when headphones are plugged in. If the socket is the type illustrated at the top of this page, with 6 terminals (or 4 for a mono connector), every pole is switched. Viewed from the back, the left set of terminals is connected to the plug when inserted, and the right set is switched - disconnected when the plug is inserted, connected to the left set of terminals when the plug is removed. For a headphone socket, the left side would be connected to the amplifier and the right side to the speakers. For unbalanced microphones, connecting the right hand terminals together shorts the input to ground when no mic is connected (avoids hum). For audio purposes , just switch the left and right signals through the socket, not the ground.

Connector Assembly Instructions

Line Connectors:

Normally solder terminals. Remember to thread the cover onto the cable before soldering. Squeeze the cable clamp shut with pliers AFTER soldering, otherwise the heat will melt the insulation.

Panel connectors:

Normally solder terminals. It is sometimes easier to mount the connector on the panel before soldering to hold it steady. Refer to the supplier's catalogue or above if in unsure of the pin arrangements.

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