tonistry.

Connections & formats

3.5mm

Also called 3.5mm jack, 1/8 inch, mini jack

The 3.5mm jack is the small round analog audio connector on phones, laptops and many portable players and headphones. It carries a stereo signal on a single plug.

3.5mm TRS · single-endedTRSshared returnRight driverR−R+Left driverL−L+
A 3.5mm TRS plug has three contacts: the tip carries the left signal, the ring the right signal, and the sleeve is a return shared by both drivers.

The plug has a tip, ring and sleeve for left, right and ground. Some versions add a fourth contact for a microphone, which is why a headset plug may not work in a headphone-only socket, and the other way around.

It is almost always single-ended, so it is not the same as a Balanced vs single-ended connection such as a 4.4mm plug. Many headphones ship with a 3.5mm cable for portable use and a 6.35mm adapter, or a second cable, for a desktop amplifier.

Many phones have dropped the socket in favor of USB or Bluetooth, so a small adapter with its own DAC is a common way to keep using wired headphones.

Where you’ll see this on tonistry.

  • 3.5mm is one of the connection types members pick when they draw a signal chain.

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