Digital optical AUDIO connection between S.Blaster Live! and a MiniDisc drive

How to make digital optical AUDIO connection between Sound Blaster Live! and a MiniDisc drive. Find out how easy you can do it yourself. If you have SBLive or any other card with digital SPDIF output, you can copy CD or record MP3 to your MD recorder. You can make copies of CD, even if you do not have any sound card. In the latter case, your CD-drive must have digital audio output, which is quite common nowadays. All you need is 250 rubles (less than 10 euro), three hours of your work, and some minor skills in soldering. You do not need open your computer!

If you want to record from SBLive to MiniDisc, here is The LIST:

1. Toshiba optical transmitter TOTX173 or TOTX176 (additionaly has a mounting hole) - 6 euro,
2. Two resistors: 8.2 KOhm and 4.7 Ohm,
3. Capacitor 100 nF,
4. A board to solder everything on,
5. 1.0 meter of thin shielded wire,
6. D15 male connector for MIDI-port (if you want to connect everything externaly),
7. Digital DIN jack: 9-pin male connector for S/PDIF port (if externaly).

If you also want to record from MiniDisc to SBLive, you need additionally

1. Toshiba optical receiver TORX173 or TORX176 (additionaly has a mounting hole) - 6 euro,
2. Inductance 0.047 mH,
3. Capacitor 100 nF,

The S/PDIF signal, which is later converted to the optical signal, is taken from the Digital DIN jack on the digital I/O card, the daughter card of SB Live. It is a 9-pin connector, described in SBLive Specifications. You need pins 1 or 2 (Ground) and pin 8 (SPDIF Out #0). The advantage of using this connector instead of RCA is that DIN jack provides the signal of TTL level (5 Volts) suitable for TOTX173 transmitter, while RCA has standard 0.5 V signal.The MIDI/joystick port is used as a power supply. Pin 8 is +5V, and pin 4 is Ground. For specifications on Joystick/MIDI adapter see midi.org. The MIDI port on the MAIN board must be used, as the MIDI ports on the daughter card are protected with 210 Ohm resistors.

The electric circuit is very simple: CIRCUIT.GIF. Sorry for the hand written graph. Instead of pin1, pin8 of SPDIF connector, input of TOTX173 can be connected to the digital audio out of a CD-ROM drive, but NOT simultaneously CD and SPDIF. You can see my 2-pin connector on some pictures below. I actually use CD digital out, when I copy CDs, because I can watch TV on my PC in the meantime. Just in case, digital audio out is a 2-pin connector, next to the 4-pin analog audio out connector on the back side of your CD-ROM drive. Shielded wire can be used both for signal connections and for power supply. Connect the shield to the ground and the central wire to the SPDIF or +5V, respectively.I fixed the board to the metal plate from old network card, in order to put it inside computer, but it is a matter of taste.

How does it look like?
Pictures 1, 2, 3, 4, 5, 6, 7, 8.

If you have comments or suggestions, email me at info.mdtrade@libero.it