David Larsson's Latest Sound Blaster Replica Puts a Feature-Packed Sound Card on IBM's MCA Bus
Offering full Sound Blaster and Adlib compatibility, this replica card makes full use of the MCA audio-routing capability.
Vintage electronics enthusiast David Larsson has designed a Creative Sound Blaster replica with a difference: it's compatible with IBM's short-lived Micro Channel Architecture (MCA), as found in selected IBM personal computer models.
"Original Sound Blaster cards for the Micro Channel bus are quite hard to come by these days," Larsson explains of the reasoning behind his design, which is a second-generation improvement on earlier work for both the MCA bus and the more common ISA bus. "It seems that most sound cards for the MCA bus has line level output only. Quite a few people have asked before for it to be louder, so here it is. I also added a volume control pot in the back."
Launched by IBM in 1987 for the PS/2 family, the Micro Channel Architecture was designed to replace the Industry Standard Architecture (ISA) — primarily, though not exclusively, because of the threat "IBM compatible" clones posed to the company's nascent personal computing business. While MCA addressed many of the shortcomings of the ISA bus, it was also entirely proprietary — and abandoned by all when the more open Peripheral Component Interconnect (PCI) standard came along in 1993.
Owing to its short lifespan, MCA hardware is thin on the ground — which is where Larsson's Sound Blaster clone comes in, standing in for the original with some handy quality-of-life improvements. Perhaps the biggest: the ability to route audio to the PC's internal speaker. "[That] is something cool that the Micro Channel bus allows but the ISA bus does not: the ability to route the output of the sound card to the internal PC speaker (and even between cards, if you want one card to record the output of another, for example)," Larsson explains. "The internal audio is amplified and thus controlled by the volume pot in the back."
Other features of the card include full Sound Blaster compatibility, Adlib OPL2 support, a gameport for joysticks with MIDI support, and a three CD-ROM audio connectors. A plastic bracket ensures solid mounting in an MCA-compatible case, while Larsson has written that metal brackets are planned as a $25 upgrade in the near future.
The MCA sound card is now available to order on Larsson's Tindie store, priced at $125. More information on the design, and the maker's other vintage card recreations, is available on Larsson's website.