Connections to balanced and un-balanced inputs. XLR, 1/4", phono

The illustrations below show the connection between balanced and un-balanced outputs on different connector types (XLR / Cannon, 14", phono/RCA/cinch) to balanced inputs on XLR and 1/4" connectors.

We are assuming that XLR pin 2 is positive and that the tip of the 1/4" plug is also positive. Check that your devices are not wired differently. 1/4" three-contact connectors are often referred to as TRS (Tip-Ring-Sleeve), as opposed to two-contact TS (Tip-Sleeve) connectors.

Balanced to balanced

In case of hum when connecting balanced outputs to balanced inputs, it is common practice to lift (disconnect) the shield (ground) at the input connector.

Unbalanced to balanced

In general, to connect an unbalanced source to a balanced input, two of the cable conductors are joined (negative/cold and sleeve).