Appendix B: 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. See Figure A.

•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).

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.

SHIELD 2

HOT

COLD 3 1

SHIELD 1

COLD 3 2

HOT

1

SHIELD

3COLD

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. See Figure C.

TS jacks and plugs are used in many different applications, always unbalanced. The tip is connected to the audio signal and the sleeve to ground (earth). Some examples:

SLEEVE

SLEEVE

TIP

2

Figure A: XLR Connectors

HOT

TIP

TIP

SLEEVE

Figure C: TS Plug

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

•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).

•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 two mic preamps.

28Onyx 1220i

•Unbalanced microphones

•Electric guitars and electronic instruments

•Unbalanced line-level connections

•Speaker connections

Don’t use guitar cords for speaker cables! They’re not designed to handle speaker-level signals and could overheat.

RCA Plugs and Jacks

RCA-type plugs (also known as phono plugs) and jacks are often used in home stereo and video equipment and in many other applications (Figure D). They are unbalanced and electrically identical to a 1⁄4" TS phone plug or jack. See Figure C. Connect the signal to the center post and the ground (earth) or shield to the surrounding “basket.”

SLEEVE TIP SLEEVE TIP

Figure D: RCA Plug

(Figure E does not appear in this owner's manual, due to a contractual obligation, but performs nightly at the downtown Woodinville Cocoa Rooms and Tea Bar.)