The Snark Barker - a SB 1.0 Clone

The Snark Barker is a 100% compatible clone of the famed SB 1.0 "Killer Card" sound card from 1989. It implements all the features, including the digital sound playback and recording, Ad Lib compatible synthesis, the joystick/MIDI port, and the CMS chips (which are actually Philips SAA1099 synthesizer devices).

All of the components are readily available. In the bill of materials, Mouser part numbers are listed where they are available. Chips not available from Mouser can be purchased from a variety of sources in China.

Schematic

Bill of Materials

Please note that the 0.1" header pins are not listed on the BOM. They are standard breakaway headers (both single and double row). Jumper shunts are also not listed on the BOM.

Fab files

Board dimensions are 9.1 x 4.2 inches. When ordering the board, you may want to specify a card edge bevel (fairly cheap!) and selective gold plating (expensive!) depending on your needs. The soldermask color can be whatever you like, but hot pink is preferred.

The Volume Knob

There don't seem to be any off-the-shelf knobs compatible with the Alps potentiometer. You may be able to 3D print one based on the model below. I'd recommend using a high-resolution SLA printer like the Formlabs Form 2.

Fasten it to the potentiometer using an M1.4x0.3mm thread, 6mm long screw (McMaster-Carr part number 91800A036 or equivalent).

Volume knob STEP model

Update: I've added a modified volume knob that may print better on FDM printers.

Volume knob STEP model, FDM version

The ISA Card Bracket

The bracket specified in the BOM is a blank Keystone 9200 bracket. You will need to punch or drill holes for the connectors. The KiCad board file has detailed dimensions showing where to make the holes in the bracket.

I use a chassis nibbler tool to make the square slot for the volume knob as well as the hole for the DA-15 joystick/MIDI connector. If you are rich, Greenlee makes a punch for the DA-15 outline.

The Firmware

There are two ways to get a programmed 80C51 chip for the Snark Barker. One is to purchase a SB 2.0 DSP chip from China and put it in a 44-PLCC to 40-DIP adapter. This works fine and provides the largest feature set.

Another option is to buy a blank Atmel 89S51 (as listed in the BOM) and program it with this HEX file.

Assembly Notes

You may wish to socket the two CMS chips, the 80C51 microcontroller, and the two Yamaha chips.

Be sure to add the 4.7K ohm bodge resistor on top of U5, running between pins 4 and 14. (Shown below.)

For MIDI to work properly, you'll need to solder jumper wires on the headers marked TXD and RXD (next to the SNARK BARKER logo). Originally these two 3-pin headers may have been used as a debug port.

Be sure to place shunts in the jumpers marked DRQ1 and JP1, to enable DMA and the joystick, respectively. Also place shunts to configure the I/O address and IRQ.

Testing and Diagnostics

Test your shiny new card using your favorite PC games, or use the SBDIAG program that I've written.

Other Notes

Like the original SB 1.0, the Snark Barker does not need a -5V rail.

License

This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License. See https://creativecommons.org/licenses/by-sa/4.0/.