APPENDIX A: Connections

“XLR” CONNECTORS

Mackie mixers use 3-pin female “XLR” connectors on all microphone inputs, with pin 1 wired to the grounded (earthed) shield, pin 2 wired to the “high” (”hot” or positive polarity) side of the audio signal and pin 3 wired to the “low” (“cold” or negative polarity) side of the signal (Figure A). All totally aboveboard and in

 

COMMON

 

 

COLD HOT

 

 

COMMON

 

 

COLD HOT

 

Figure A:

2

HOT

 

3

COLD

XLR Connectors

1

COMMON

 

 

 

full accord with the hallowed standards dictated by the AES (Audio Engineering Society).

Use a male “XLR”-type connector, usually found on the nether end of what is called a “mic cable,” to connect to these inputs.

•Stereo Headphones, and rarely, stereo microphones and stereo line connections. When wired for stereo, a 1⁄4" TRS jack or plug is connected tip to left, ring to right and sleeve to ground (earth). Mackie mixers do not directly accept 1-plug-type stereo microphones. They must be separated into a left cord and a right cord which are plugged into the two mic preamps.

You can cook up your own adapter for a stereo microphone adapter. “Y” two cables out of a female 1⁄4" TRS jack to two male XLR plugs, one for the Right signal and one for the Left.

•Balanced mono circuits. When wired as a balanced connector, a 1⁄4" TRS jack or plug is connected tip to signal high (hot), ring to signal low (cold), and sleeve to ground (earth).

•Unbalanced Send/Return circuits. When wired as send/return “Y” connector, a 1⁄4" TRS jack or plug is connected tip to signal send (output from mixer), ring to signal return (input back into mixer), and sleeve to ground (earth).

1⁄4" TRS PHONE PLUGS AND JACKS

“TRS” stands for Tip-Ring-Sleeve, the three connections available on a “stereo” 1⁄4" or “balanced” phone jack or plug. See Figure B. TRS jacks and plugs are used in several different applications:

RING SLEEVE

SLEEVE RING TIP

TIP

RING

TIP

SLEEVE

Figure B: 1/4” TRS plugs

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