32
APPENDIX A: CONNECTIONS
“XLR” CONNECTORS
Mackie mixers use 3-pin female “XLR” con-
nectors 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 sig-
nal (Figure A). All totally aboveboard 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.
2
2
3
1
1
SHIELD
COLD
HOT
SHIELD
COLD
HOT
3
SHIELD
COLD
HOT
3
2
1
SLEEVE
TIP
SLEEVE
TIP
RING
RING
TIP
SLEEVE
RING
Figure B:
1
⁄
4
" TRS Plugs
Figure A: XLR Connectors
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.
SLEEVE
TIP
TIP
SLEEVE
TIP
SLEEVE
Figure C: TS Plug
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
" 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 ex-
amples:
• Unbalanced microphones
• Electric guitars and electronic instruments
• Unbalanced line-level connections
TRS jacks and plugs are used in several different
applications:
• Stereo Headphones, and rarely, stereo micro-
phones 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.
SWITCHED
1
⁄
4
" PHONE JACKS
Switches can be incorporated into
1
⁄
4
" phone
jacks, which are activated by inserting the plug.
These switches may open an insert loop in a
circuit, change the input routing of the signal or
serve other functions. Mackie uses switches in the
channel insert and bus insert jacks, input jacks
and AUX returns. We also use these switches to
ground the line-level inputs when nothing is
plugged into them.
In most cases, the plug must be inserted
fully to activate the switch. Mackie takes
advantage of this in some circuits, specifying
circumstances where you are to insert the plug
only partially. See
Special Mackie
Connections
, later in this section.
