How To Hook Your Sound Card Up To Play Through Your
Hi-Fi

Consumer PC Sound cards typically put out a signal of 1 volt when playing an audio file that is recorded at full scale per the AC 97 standard. Some cards can put out 2 volts. This is sufficient to drive most Hi Fi equipment given that most CD players put out about 2 volts, and are among the loudest of all audio equipment. PC Sound cards, even when not designed to drive speakers still present a low source impedance in the 32 to 150 ohm range. Therefore they can drive relatively long lines without treble losses.

Professional PC sound cards can generally be adjusted to deliver signals that correspond to the -10  or +4 standard. They generally deliver a signal that is about 10 dB above the standard level when playing an audio file that is recorded at full scale.  It is not unusual for PC sound cards to have balanced output connectors, but be impedance balanced. In other words, one of the two balanced outputs (tip or pin 2) is active, and the other (ring or pin 3) is connected to ground via a resistor of about 150 ohms.

Here is a general procedure:

1. Obtain a cord from a retailer that has appropriate plugs on both ends. 

You may need to extend a standard adaptor cord with standard cable unions and long standard cables. Standard shielded audio wire or coax is usually appropriate for all connections of this kind. Nonstandard cables and booster amplifiers are generally only  needed  for runs that are well in excess of several hundred feet.

If you have problems with unusual combinations of connectors or inputs or outputs please see http://www.rane.com/note110.html  . 

If you need to solder connectors  and don't know how, please see http://www.allsands.com/HowTo/howtosolder_cc_gn.htm .

2. Set the volume on your Hi Fi to minimum.

3. Select the correct input and play some typical sound file on your PC.

4. Adjust the volume as desired. If the sound is too high or too low on the stereo with desired volume settings at the stereo,  use the Windows Mixer or sound card vendor-provided program to adjust levels to suit.

5. If you want to drive PC speakers and a Hi Fi at the same time the simplest approach is to use a splitter cable. Because of the levels and impedance involved this will probably not cause problems with sound quality. You may have to adjust the volume controls at the PC speakers to suit your use of the PC speakers after you have adjusted the level controls in the PC to suit your use of the HiFi.

6. If there is hum or noise, its probably due to a ground loop. Please use  the following references for assistance in resolving the ground loop:

http://www.securityaudio.com/groundloops.htm

http://www.epanorama.net/documents/groundloop/index.html

Good luck!