- Published on
Beavis Ultrasound PnP ISA Sound Card Replica
- Authors
- Name
- DeepHorus
The Beavis Ultrasound PnP, an open-source replica of the Gravis Ultrasound PnP ISA sound card, has been released to the public. This project aims to preserve the legacy of one of the most iconic sound cards of the 1990s, which was renowned for its high-quality audio output and hardware-based mixing capabilities. The replica is designed to be a faithful recreation, with the entire schematic and reverse-engineered source code of the programmable logic device (GAL) made available.
The Gravis Ultrasound PnP was a popular choice among PC gamers and musicians during the early multimedia era, but original cards have become increasingly scarce and expensive. The Beavis Ultrasound PnP seeks to fill this gap by providing a modern, buildable alternative. The design centers around the AMD InterWave chip (AM78C201), which integrates most of the sound card's functionality, making the board relatively simple in construction.
The board measures 8.2 by 4.2 inches and uses a four-layer PCB design. It requires an AMD InterWave chip, a sample ROM (typically the IW78C21M1, but a 27C800 EPROM with downloaded samples can be substituted), and a 93C66 EEPROM for plug-and-play configuration. The creator has provided the necessary binary files and programming utilities, such as the 'pnp_reverse.py' script for custom configurations, though standard programming can be done using a TL866 programmer.
One notable aspect is that the design includes a GAL chip (U14) that handles ISA-to-IDE buffering and address decoding, enabling CD-ROM IDE functionality. However, if this feature is not needed, the GAL can be omitted. The creator also notes that the ferrite beads for voltage regulation can be replaced with zero-ohm resistors or wire, and the dual op-amps (LM833 or JRC5532) can be substituted.
As of now, the Beavis Ultrasound PnP has not been fabricated or tested. The creator explicitly states that the board is built at the user's own risk, as no fabrication package has been generated. This cautious approach reflects the complexities of retro hardware reproduction, where even minor errors can render a board non-functional.
The implications of this project are significant for the retro computing community. It provides a low-cost, open-source alternative to expensive original cards, allowing enthusiasts to experience authentic GUS audio in vintage systems. The release of the GAL source code also enables further experimentation and potential improvements, such as customizing the ISA timing or adding new features.
Reactions from the vintage PC community are expected to be positive, given the passionate interest in preserving classic hardware. However, the lack of testing means that early adopters may face challenges, and the project's success will depend on community debugging and validation. Future developments could include a revised version after testing, or derivative designs that incorporate additional features like OPL3 synthesis.
In conclusion, the Beavis Ultrasound PnP represents a valuable contribution to retro computing preservation. While it remains untested, its open-source nature invites collaboration and iteration. If successfully fabricated, it could become a staple for enthusiasts seeking to build authentic DOS gaming machines. The project also highlights the growing trend of open-source hardware clones that keep vintage technology alive.
