Snark Barker MCA Adds Sound Blaster Support to PS/2 Computers

Adding digital sound to a PS/2 computer just became easy and affordable, thanks to vintage computer enthusiast Eric Schlaepfer. He adapted his Snark Barker ISA card to provide a Sound Blaster 1.0 compatible card for Micro Channel systems. Snark Barker adds FM-synthesized sound, MIDI support, and a joystick port to an MCA-based system without spending a fortune.

The IBM PS/2 computer introduced many improvements to the original PC architecture. While many of those became standard in the industry, one was not so popular. The, then, new Micro Channel Architecture (MCA) slots were high-performance replacements for the original PC's Industry Standard Architecture (ISA) slots. Eventually, the more open Peripheral Component Interconnect (PCI) bus superseded MCA. For a detailed look at Micro Channel, check out Schlaepfer's MCA tutorial.

Despite the hardware improvements, the PS/2 still only included a simple piezo buzzer. To add digital sound or music, PC users needed a soundcard like the Sound Blaster. Creative created a version of their popular card that worked with MCA. You can sometimes find them today, but they fetch ridiculously high-prices on auction sites. These high prices are what make an MCA version of the Snark Barker so appealing.

A Yamaha YM3812 sound chip provides Snark Barker's FM-synthesis, just like the original Sound Blaster. Acquiring these chips is tricky since they are no longer in production. If you use grey-market providers, Schlaepfer recommends purchasing a couple at a time to increase the likelihood of receiving a functional IC! Additionally, the design also needs a NE558 quad timer, which also comes from dubious sources today. The rest of the design uses readily available parts — for example, a Xilinx CPLD interfaces between the Micro Channel Bus and the card's onboard logic.

Even after getting a board produced, populated, and the EEPROMs programmed, you'll need to think about the mechanicals. Nobody manufactures MCA brackets. There are three options to add the appropriate bracket: removing them from existing cards, 3d print one, or use the card without one. STL files are available for printing front and rear brackets. You will need to use a few (metal) screws as fasteners.

So far, Schlaepfer confirmed that the Snark Barker MCA works in an IBM PS/2 Model 50Z, Model 95, and an NCR System 3400. Though, he warns that a PS/2 Model 80 with memory expansion may result in erratic behavior. Those of us familiar with MCA's legacy are no stranger to weird configuration problems.

If you're ready to use the business-oriented system to play games, then head over to the Snark Barker MCA GitHub repository. There you can find build notes, complete bill-of-materials, schematics, and KiCad board files. Schlaepfer's website also has a detailed write-up on the original ISA Snark Blaster covering how it operates.