Studio reference

Audio Connector Wiring

Connector views, pin numbers and common studio wiring conventions.

Safety: Use at your own risk. Verify all wiring before use; AC mains wiring should be performed only by qualified persons with power disconnected.

Analog audio

Unbalanced analog

RCA / Phono

Center — Signal / hot
Shell — Shield / ground

Unbalanced instrument / line

1/4-inch TS

Tip — Signal / hot
Sleeve — Shield / ground

Balanced mono / stereo

1/4-inch TRS

Balanced: Tip hot (+), Ring cold (−), Sleeve shield
Stereo: Tip left, Ring right, Sleeve common

Stereo headphones / consumer line

3.5 mm TRS

Tip — Left
Ring — Right
Sleeve — Common

Professional headphone connection

1/4-inch Stereo Headphones

Tip — Left
Ring — Right
Sleeve — Common / return

Headset / mobile audio

3.5 mm TRRS

CTIA and OMTP standards differ
Verify microphone and ground contacts before wiring

Balanced audio — mating face

XLR 3-pin Male

Pin 1 — Shield / ground
Pin 2 — Hot (+)
Pin 3 — Cold (−)

Balanced audio — mating face

XLR 3-pin Female

Pin 1 — Shield / ground
Pin 2 — Hot (+)
Pin 3 — Cold (−)
Female physical layout mirrors male when viewed from mating face

Professional patchbay

Bantam / TT

Tip — Hot (+)
Ring — Cold (−)
Sleeve — Shield / ground

Console insert — common convention

TRS Insert

Tip — Send
Ring — Return
Sleeve — Common
Some equipment reverses send and return

Digital audio, data & control

110-ohm balanced digital audio

AES3 / AES-EBU XLR

Pin 1 — Shield
Pin 2 — Data +
Pin 3 — Data −

75-ohm coaxial digital audio

RCA S/PDIF

Center — Signal
Shell — Return / shield

Word clock / AES3id

BNC

Center — Signal
Shell — Return / shield
Use 75-ohm cable and proper termination where required

Optical S/PDIF / ADAT

TOSLINK

Optical connection — no electrical pinout
Commonly carries S/PDIF or ADAT Lightpipe depending on equipment

MIDI current-loop interface

MIDI 5-pin DIN

Pins 4 and 5 — MIDI signal current path
Pin 2 — Shield on MIDI OUT under standard practice
Pins 1 and 3 normally unused for classic MIDI

Audio networking / Ethernet

EtherCON / RJ45

Uses standard Ethernet twisted-pair wiring
T568B is common; T568A is also standards-compliant
Dante and AES67 do not use a special connector pinout

USB host / legacy computer connection

USB Type A

Pin 1 — VBUS
Pins 2/3 — USB 2.0 data − / data +
Pin 4 — Ground

Traditional audio-interface peripheral connector

USB Type B

Pin 1 — VBUS
Pins 2/3 — USB 2.0 data − / data +
Pin 4 — Ground

Modern USB audio / data / power

USB-C

24-contact reversible connector
USB-C describes the connector, not guaranteed speed, power or protocol
Cable capabilities vary; use a cable specified for the required audio/data function

Legacy IEEE 1394a audio interface

FireWire 400

Common 6-pin powered and 4-pin unpowered variants
Legacy reference — verify device and cable before connection

Legacy IEEE 1394b audio interface

FireWire 800

9-pin connector used by many later professional audio interfaces
Adapters do not make FireWire equivalent to USB or Thunderbolt

Speakers & power

Loudspeaker connection

Speakon NL2

1+ — Positive
1− — Negative

Bi-amp / multiway loudspeaker

Speakon NL4

1+ / 1− — Channel 1
2+ / 2− — Channel 2

Common professional DC power

4-pin XLR DC

A frequent convention is Pin 1 negative and Pin 4 positive
Not universal — voltage and pinout must be verified before connection

Common rack-equipment AC mains

IEC C13 / C14

L — Line / live
N — Neutral
PE — Protective earth
Observe connector-side orientation; follow molded L, N and earth markings

Higher-current equipment AC mains

IEC C19 / C20

L — Line / live
N — Neutral
PE — Protective earth
Common on higher-power amplifiers, UPS units and distribution equipment

Locking professional AC mains

powerCON

Line, neutral and protective-earth contacts
Legacy blue/gray powerCON and newer TRUE1 families differ
Do not assume different powerCON families are interchangeable

AC mains wiring

NEMA 5-15 / common 120 V

USA / Canada — 3-wire

Black — Hot / Line (L)
White — Neutral (N)
Green or green/yellow — Equipment ground (PE)
Brass screw — Hot; silver screw — Neutral; green screw — Ground

Polarized 2-wire cord

USA / Canada — 2-wire

Black — Hot / Line (L)
White — Neutral (N)
Narrow blade — Hot; wide blade — Neutral
No equipment grounding conductor

Current IEC harmonized flexible-cord colors

IEC / Europe / UK / Australia

Brown — Line / Live (L)
Blue — Neutral (N)
Green/yellow — Protective earth (PE)
These colors are widely used in Europe, UK, Australia/New Zealand and IEC-based equipment

Older UK wiring — reference only

UK — legacy colors

Red — Live
Black — Neutral
Green or green/yellow — Earth
Do not assume age or compliance from color alone

Older AU/NZ wiring — reference only

Australia / New Zealand — legacy

Red — Active / Line
Black — Neutral
Green — Earth
Modern equipment generally follows brown / blue / green-yellow IEC colors

Multipin & legacy

8-channel balanced analog — TASCAM convention

DB25 / D-sub

Eight balanced channels use hot, cold and ground conductors
Common on modern multichannel interfaces and outboard gear
Other DB25 standards exist — verify equipment

Stereo / dual-channel / control

XLR 5-pin

Audio convention often uses Pin 1 shield, 2/3 channel 1, 4/5 channel 2
Also used for DMX and other applications — verify before connecting

Tube microphones / proprietary multipin audio

XLR 7-pin

Frequently used between tube microphones and power supplies
There is no universal tube-microphone 7-pin assignment
Use the microphone manufacturer exact documentation

Vintage European audio

DIN / Tuchel

Tuchel describes several connector families and pin counts
No single universal audio pinout exists
Identify the exact connector and equipment standard before wiring

Common Cable Wiring

XLR ↔ XLR balanced

1 → 1 shield/ground 2 → 2 hot (+) 3 → 3 cold (−)

XLR ↔ TRS balanced

XLR 1 → Sleeve shield XLR 2 → Tip hot (+) XLR 3 → Ring cold (−)

TRS ↔ TRS balanced

Tip → Tip hot Ring → Ring cold Sleeve → Sleeve shield

TS ↔ TS instrument

Tip → Tip signal Sleeve → Sleeve shield/return

TRS insert → 2 × TS

Common convention: TRS Tip → Send TS Tip; TRS Ring → Return TS Tip; sleeves common. Verify the console manual.

RCA ↔ RCA

Center → Center signal Shell → Shell shield/return

Speakon ↔ Speakon

Wire corresponding contacts end-to-end: 1+ → 1+, 1− → 1−; NL4 adds 2+ and 2− as required.

MIDI DIN ↔ DIN

Use a correctly wired MIDI cable with corresponding DIN contacts. MIDI signal current uses pins 4 and 5; pin 2 is used for shield at MIDI OUT under standard practice.

Ethernet T568B ↔ T568B

1 white/orange · 2 orange · 3 white/green · 4 blue · 5 white/blue · 6 green · 7 white/brown · 8 brown.

Interconnection Notes

Balanced → unbalanced

There is no single wiring rule appropriate for every output topology. Transformer-balanced, electronically balanced and impedance-balanced outputs can require different treatment of the cold conductor. Check the equipment documentation before tying pin 3/ring to ground.

AES3 XLR ↔ AES3id BNC

AES3 balanced XLR is nominally 110 Ω; AES3id coaxial BNC is 75 Ω. A physical XLR-to-BNC adapter does not provide the required impedance conversion. Use the appropriate transformer/interface.

ADAT vs. optical S/PDIF

Both can use a TOSLINK optical connector, but they are different digital formats. Identical connectors do not imply protocol compatibility.

Word clock

WORD CLOCK OUT75 Ω coaxDEVICE IN/THRU75 Ω coaxLAST DEVICE
75 Ω TERMINATION

Terminate the end of a daisy chain at 75 Ω unless the final device provides switchable or automatic termination. Do not double-terminate.

Patchbay Normaling

Full-normal

TOP / SOURCE↓ NORMAL ↓BOTTOM / DESTINATION

With no plugs inserted, top feeds bottom. Inserting a plug into either jack breaks the normal connection.

Half-normal

TOP / SOURCE↓ NORMAL + MULT ↓BOTTOM / DESTINATION

Plugging into the top jack can mult the source without breaking the normal path; inserting into the bottom normally breaks it.

Thru / non-normal

Before you solder

Connector view matters. Each connector is shown from both the soldering side and the connection/mating side. Those views are mirror images where the physical contact layout requires it. Follow the pin numbers or terminal markings molded into the actual connector.

AC mains safety: conductor colors and connector diagrams are references, not a substitute for testing or applicable electrical codes. Flexible-cord colors can differ from fixed-building wiring, especially by country and installation age. Disconnect mains power before opening or wiring a connector; when in doubt, use a qualified electrician or technician.

Balanced analog: modern XLR convention is pin 2 hot. TRS balanced wiring uses tip hot, ring cold and sleeve shield.

Legacy and multipin equipment: Tuchel/DIN, DB25, inserts and DC-power connectors are particularly likely to vary by manufacturer. Connector shape alone does not establish electrical compatibility.

Digital cabling: use the specified cable impedance. An RCA or BNC plug fitting physically does not make ordinary analog patch cable appropriate for a 75-ohm digital link.