schlae/beavisultrasound

Beavis Ultrasound PnP is an open source hardware replica of an old sound card called the Gravis Ultrasound PnP, a piece of audio hardware from the early days of PC gaming. This is not software you install and run, it is a full circuit board design you can actually build yourself, including the schematic and the reverse engineered logic for one of the original chips on the board. To build the card, you need a specific chip called the AMD InterWave, part number AM78C201, since almost all of the sound card function lives inside that one chip. The author is upfront that they have not yet fabricated or tested this exact board, so building it is at your own risk. The repository includes a schematic PDF, and the finished board design is 8.2 by 4.2 inches across four layers. The README walks through assembly in detail. Some parts, like the dual op amps, can be swapped for compatible alternatives if the exact listed part is hard to find. Some components, like certain ferrite beads, do not have confirmed values and can be replaced with plain wire or a zero ohm resistor. A couple of jumper positions are left unpopulated because they were only useful for testing signal isolation during the original design process. Two chips need to be programmed before the card will work. One is a sample ROM containing built in sounds, which you may need to find and burn yourself if the original chip is unavailable. The other is an EEPROM holding the plug and play configuration, which you program using a device programmer and a provided binary file. A small Python script is included that reverses the bit order of that configuration data, mainly for people who want to experiment with custom settings rather than for the standard setup. The README does not mention a license for this hardware design.