APPENDIX B: Connectors

“XLR” CONNECTORS

Mackie amplifiers use 3-pin female “XLR” connectors on each input, 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”

SHIELD 2

HOT

COLD 3 1

SHIELD 1

COLD 3 2

HOT

1SHIELD

3COLD

(output from mixer), ring to signal return (input back into mixer), and sleeve to ground (earth).

•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 sig- nal low (cold), and sleeve to ground (earth). This is the application used for the inputs to Mackie amplifiers.

1⁄4" TS PHONE PLUGS AND JACKS

“TS” stands for Tip-Sleeve, the two connections available on a “mono” 1⁄4" phone jack or plug (Figure C). TS jacks and plugs are used in many different applications, always unbal-

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Figure A: XLR Connectors

HOT

anced. The tip is connected to the audio signal and the sleeve to ground (earth). Some examples:

(“cold” or negative polarity) side of the signal (Figure A). All totally above-board and in 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 a female XLR jack.

1⁄4" TRS PHONE PLUGS AND JACKS

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

•Unbalanced microphones

•Electric guitars and electronic instruments

•Unbalanced line-level or speaker-level connections

SLEEVE

SLEEVE TIP

TIP

 

Figure C: TS Plug

TIP (HOT)

SLEEVE (SHIELD)

UNBALANCING A LINE

RING SLEEVE

SLEEVE RING TIP

TIP

RING (COLD)

TIP (HOT)

In most studio, stage, and sound reinforcement situations, there is a combination of balanced and unbalanced inputs and outputs on the various pieces of equipment. This usually will not be a problem in making

Figure B: 1⁄4" TRS Plugs

SLEEVE (SHIELD)

connections.

•Stereo Headphones, 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).

•Unbalanced Send/Return circuits. When wired as a send/return “Y” connector, a 1⁄4" TRS jack or plug is connected tip to signal send

•When connecting a balanced output to an unbalanced input, be sure the signal high (hot) connections are wired to each other, and that the balanced signal low (cold) goes to the ground (earth) connection at the unbalanced input. In most cases, the balanced ground will also be connected to the ground at the unbal- anced input. If there are ground-loop problems, this connection may be left disconnected at the balanced end.

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