connectors
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published: Nov-30-2025
most common audio connectors for analog mono/stereo signals
Below the most common connectors used in home stereo and studio used for analog audio signals.
The 4.4mm TRRRS (Pentaconn) is getting more common and mostly used for balanced headphone connections.
Tip= L+, Ring1= L-, Ring2= R+, Ring3= R-, Sleeve= common/ground
The TRRS connector is found in 2.5mm and 3.5mm diameters.
The 2.5mm TRRS is intended for balanced connections.
Tip= R-, Ring= R+, Ring2= L+, Sleeve= L-
The 3.5mm TRRS is NOT intended for balanced connections but rather for single ended stereo + one for microphone/remote (often microphone and remotre are combined).
There are 2 different standards here Apple uses CTIA (Cellular Telecommunications and Internet Association) and others use OMTP (Open Mobile Terminal Platform)
CTIA: Tip= L, Ring1= R, Ring2= ground, Sleeve= mic/remote
OMTP: Tip= L, Ring1 = R, Ring2= mic/remote, Sleeve= ground
As these 2 standards have the ground and mic/remote switched on can encounter incorrect operation/sound.
Below a few possible pinning configurations of gear using 4 pin TRRS plugs.
As most of these aren’t specifically for headphones below a listing of the 4 main configurations of this TRRS plug.
You need to find out what pinning is the correct one for the headphone AND is present on the amplifier/source.
To make things worse the 3.5mm TRRS (as well as 2.5mm TRRS) are also used in headphone cups themselves along with other (proprietary) connectors.
The 3.5mm TRS connectors allows these headphones to use a single cable entry for both channels and still be able to use the headphone balanced. Sometimes 4-pin mini XLR is used or some proprietary connector.
There are no real standards here so manufacturers can connect them the way they see fit.
The TRS connector is found in 2.5mm, 3.5mm and 6.3mm variants.
The 6.3mm TRS connector is used in stereo but also in balanced mono in professional gear but also for effects.
Fortunately these are wired in the same way; tip to tip, ring to ring and sleeve to sleeve.
These cables are universal in that sense.
Stereo TRS connector: Tip= L, Ring= R, Sleeve= ground
Pro usage:
Balanced mono (6.3mm) TRS jack: Tip= signal +, Ring= signal –, Sleeve= ground
Inserts (6.3mm TRS): Tip= send(out), Ring= return(in), Sleeve= ground
In some rare (portable mono) situations the same config is used with 3.5mm TRS jack.
The TS plug is found in 2.5mm, 3.5mm and 6.3mm diameters.
They are always used for mono signals and sometimes as switch.
TS plug: Tip= signal, Sleeve= ground or is used as a switch contact.
There is also a so-called airplane adapter using 2x 3.5mm TS jack at a fixed distance where L and R have their own pin.
For interlinks the most common connectors are RCA connectors (also called tulip or phono connectors) and 3-pin XLR connectors. One connector for each channel.
On some devices XLR-3 sockets are combined with 6.3mm TRS jack as shown on the right.
The XLR connectors are big but have a better contact and make ground connection before the signal pins.
XLR connectors can be used balanced and single-ended and is found in professional gear (just like the 6.3mm jack) but also on the ‘better’ (read more expensive) home audio equipment.
The RCA are only single ended and have the annoying property that in most cases the signal wire is connected before the ground. This can cause a momentary (very loud) hum when inserting or disconnecting the connector. Also the screen contact can be problematic.
Often RCA connectors for stereo are color coded.
Right is usually red. For left most used is white, black and even blue. Video = yellow, SPDIF = orange.
Alas … it is so common it is hard to get rid of.
RCA connectors are also used for digital (SPDIF) and video signals.
RCA: pin= signal, Shield= ground.
XLR 3-pin: 1 = ground, 2 = signal + (hot), 3 = signal – (cold)
The XLR 4-pin is used for balanced (differential) and SE headphone outputs.
balanced: 1= L+, 2= L-, 3= R+, 4= R-
single ended: 1= L, 2= ground, 3= R, 4= ground
The XLR 4 pin is also used for other purposes, below the pinning for these.
converters/adapters
There are all kinds of converters/cables.
Some of them can indeed be used in certain circumstances and others really should not be used.
For headphone cables one can use simple rules for using converter:
Mostly O.K. Single ended outputs (3.5mm, 6.3mm TRS) > balanced headphone cable connectors (4.4mm Pentaconn, XLR 4-pin).
NOT O.K. Balanced headphone outputs (4.4mm Pentaconn, XLR 4-pin) to TRS headphone connectors this is because that ‘converter cable’ can short the L- and R- outputs of the amplifier possibly resulting in damage to the amplifier.
For interlinks one can go from XLR to RCA and also go from RCA to XLR but these require different cables with different wiring.
DIY-Audio-Heaven 