The Digital Sound Board 2 Demystified (DSB2)

I get asked many questions about arcade hardware but nothing seams to be less understood then the Digital Sound Board 2. So in this post, I will explain a bit of what I know about the DSB2 boards.

First of all, this board is ONLY used in the following games:

Top Skater (Sega Model 2 game)
Sega Rally 2
Daytona 2
Star Wars Trilogy
Spikeout Digital Battle Online
Spikeout Final Edition (Slightly patched version of the above)
Lost World Special (Full scale attraction version of the game)

As you can see, other then Top Skater, all of the games that need this board are Sega Model 3 games. Keep in mind, if you try to run one of these games without a DSB2, it will work perfectly fine, it will just not have background music, only sound effects. Another thing to know is, a DSB2 board is 100% universal and will work with any listed game, the only thing you must have done is installed the proper sound roms for the game you are working it with. I have received many DSB2 boards, One had Sega Rally 2 roms in it and the other had Star Wars Trilogy roms in it. I got my trusted rom burner guy to make me some Spikeout Digital Battle Online sound roms that I needed.

The Next thing to talk about is the confusion about caged vs uncaged DSB2 boards. The pcb is a fairly small board (as seen below) with multiple sockets for sound roms and many headers for I/O. Some people tend to run the pcb as just a bare board mounted inside their arcade cabinet with pcb feet. While the boards often came from Sega in a small metal cage similar to many of Sega's boards at the time. These cages not only protected the DSB2 but also made it easier to mount or stack if the board was used outside a cabinet. The biggest problem with the filter board on the DSB2 cage is that it reverses the pin headers on most of the inputs. So if you have a 6 pin header where pin 1 on the board was +5, if you have this DSB2 is in a cage, that +5 is now on pin 6 of that input on the filter board.


A DSB2 without cage with wires


Caged DSB2 board

As I had mentioned above, the sound effects are generated by the arcade board itself, but the music is generated by the DSB2. This is achieved by connecting the Model 3 (I have no knowledge of Top Skater's pinout) to the DSB2 via the 7 pin CN9 connector on the far right side of the Model 3's filter board. If your model 3 lacks this connector, you will need to source a filter board with CN7, CN8 and CN9 with populated pins as this will not work without those connectors. From my understanding the sound effects come out of CN7 just like any normal Model 3. CN7 and CN8 will both be used for sound effects if surround sound mode is enabled. If you are using a normal 2 speaker setup, all you need to worry about is CN7. The cable from CN9 on the Model 3 will connect to the CN6 on the DSB2. This connects the 2 boards and lets them send data back and forth. If the boards are running, the lights on the DSB2 should be blinking indicating data transmission. CN8 on the DSB2 filter is for power. The ground, +12v and +5v will need power on this connector or your sound board will do nothing at all. CN9 and CN10 on the DSB2 filter are used for music Output. Both of these (like CN7 & CN8 from the Model 3) would be used if you were using surround sound, only CN9 is needed if you are only using 2 speakers. Basically from here you just need to feed CN7 from the Model 3 and CN9 from the DSB2 filter board into a Mixer and then from the mixer to amp and unamplified speakers or directly from the mixer if you are using amplified speakers. There are many types of mixer boards from ones mainly used in arcade setups to ones used in audio/visual setups. Basically any mixer should do the trick.

The hardest part of of this whole thing is getting the DSB2 and Model 3 boards working properly and talking to each other. Once the lights on the DSB2 are blinking, you can test your CN9 and see if music is playing, and worry about your mixer from there. Of course having proper roms on the DSB2 is needed as well as this whole thing will not work at all if either you have the wrong roms or the roms are burned improperly as the first roms I received for this were burned on the wrong size chips and did not work. If you have any more questions about this whole crazy setup, feel free to contact me and I will try to help you.