LABS' BlasterBoard Uses an ATmega328, OPL2 to Offer Sound Blaster 2.0 Support to Any ISA-Capable PC

Vintage computing enthusiast LABS has launched an eight-bit sound card for the Industry Standard Architecture (ISA) bus, dubbed the BlasterBoard and designed to replace now hard-to-find Sound Blaster 2.0 parts.

"My initial idea was to create a sound card using discrete off-the-shelf components to play some games from the past on my ancient 486 PC," LABS writes of the project's inspiration. "I did not power up the machine since early '90s, it was just collecting dust at the attic. But after watching some retro gaming videos the nostalgic inspiration grew and I decided to give it a try."

"The machine was thoroughly cleaned, powered up and booted into MS-DOS perfectly. Some games were still installed on its hard drive, but there was a problem — the machine lacked a sound card. Buying one was not the way I wanted to go, but making one myself from scratch was a real dive into retro computing, so I got to work immediately."

The project is centred around two key components: A Microchip ATmega328P microcontroller provides PCM and ADPCM waveform playback via an MCP4901 digital-to-analog converter (DAC), while an original Yamaha OPL2 chip offers FM synthesis. The design also includes an input for CD audio, complete with noise cancellation circuit, another input for the internal PC speaker, a built-in analog mixer with dedicated volume knobs for each source, and line-level plus amplified headphone outputs."

"I followed [Creative] Sound Blaster 2.0 compatibility for its widest support of DOS games and simple design," LABS continues. "To make it even simpler I dropped useless sound recording ability and a game port of the original card, but added CD audio and PC speaker inputs, so the card could support any DOS game that produce any sound at all."

"It took about a month of intensive work before I was able to hear a legible PCM sound coming from the speakers. Despite it was just a heap of breadboards and wires, the excitement of hearing an explosion sound of Duke 3D logo was over the top! Two more months I was struggling with noise reduction, solving compatibility issues, prototyping and polishing software and hardware. But persistence did its job. Windows 98 finally detected the card automatically upon install and named it officially 'Sound Blaster or compatible.'"

While the design was built for personal use, it is being made available as a limited-run kit which includes a PCB, all components, ISA mounting bracket, connection wires, and a printed assembly manual; for those who would prefer to go plug-and-play, assembled versions are also available.

The BlasterBoard is now available from LABS' Tindie store, alongside a wealth of technical documentation, priced at $99 in kit form or $149 assembled; board layouts and firmware files can be found on GitHub.