Sound card

As amplifiers don't know anything about PC audio, the audio stream must be converted to an output suitable for a amplifier.

This can be is analogue (RCA or XLR) or digital by wire (S/PDIF, AES/EBU) or optical (Toslink).

The conversion to analogue is done by a DAC.

In PC speak it is done by a sound card.

Of course there is a DAC chip on board but often sound cards also offer recording facilities (the reverse, AD conversion)