33
APPENDIX C: Connectors
(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 connec-
tions available on a “mono” 1⁄4" phone jack or
plug (Figure C). TS jacks and plugs are used
in many different applications, always unbal-
anced. The tip is connected to the audio signal
and the sleeve to ground (earth). Some
examples:
• Unbalanced microphones
• Electric guitars and electronic
instruments
• Unbalanced line-level or speaker-level
connections
UNBALANCING A LINE
In most studio, stage, and sound reinforce-
ment 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
connections.
• 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.
“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”
(“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:
• 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
2
2
3
1
1
SHIELD
COLD
HOT
SHIELD
COLD
HOT
3
SHIELD
COLD
HOT
3
2
1
Figure A: XLR Connectors
SLEEVE (SHIELD)
TIP
SLEEVE
TIP (HOT)
RING (COLD)
RING
TIP
SLEEVE
RING
Figure B:
1
⁄
4
" TRS Plugs
SLEEVE (SHIELD)
TIP (HOT)
TIP
SLEEVE
TIP
SLEEVE
Figure C: TS Plug
