The following description shows the balanced analog audio input connection to external unbalanced and/or stereo audio sources.

An unbalanced source can be a chinch or a jack plug.

In some cases ground loops can generate humming noise. In this case use audio transformer to electrically isolate the digital audio matrix from the external device.

Connect an unbalanced analog audio source to a balanced analog audio input

Connect

To

Unbalanced analog audio source

Balanced analog audio input

GND

'Audio in –' (3) and GND (2)

'Signal'

'Audio in +' (1)

Connect an unbalanced stereo analog audio source to a balanced analog audio input

Connect

To

Unbalanced analog audio stereo source

Balanced analog audio input

GND R and GND L in parallel

'Audio in –' (3) and GND (2)

Signal ‘R+' and signal 'L+' via 2 resistors in parallel

'Audio in +' (1)

The value of the resistor 'R' depends on the internal resistance of the analog audio source and is typically 10k or 47k.

Connect a balanced stereo analog audio source to a balanced analog audio input

Connect

To

Balanced analog audio stereo source

Balanced analog audio input

GND R and GND L in parallel

GND (2)

Signal ‘R-' and signal 'L-' via 2 resistors in parallel

'Audio in -' (1)

Signal ‘R+' and signal 'L+' via 2 resistors in parallel

'Audio in +' (3)

The value of the resistor 'R' depends on the internal resistance of the analog audio source and is typically 10k or 47k.