I'm basing this section around my Intel based Linux system which is running Redhat 5.2, but should be reasonably distribution neutral. I'll be working on the Sparc platform version shortly. Naturally a reasonable prerequisite is a working soundcard. Setting up for Analogue Audio Capture. Firstly, set up your audio.
Most audio devices have a Line output sockets.
Line level is a standard that specifies what voltage and current the audio device will send out. If I remember correctly it is 500mA for domestic and Semi Pro devices, and 750mA for Pro audio devices. I would guess that the standard set for most soundcards will be 500mA, but some of the newer Pro audio may be to the higher standard It shouldn't make too much difference unless you are recording at very high levels. Turntables can be more of a problem, see below for more information. You could capture audio from VCR's as well.