Russ built this vintage DIY beauty 25 years ago to demonstrate the abilities of a now classic/rare chip -
Handmade SN94281-based synth I made back in 1983. The device won the Grand Champion prize at the York County Science and Engineering fair — I was 12 years old at the time. Last year at this time, I decided to restore it to working order for its 25th birthday. It is basically a “breakout box” for the Texas Instruments SN94281 Complex Sound Generator chip. All features of the chip are available as front panel knobs or multi-position switches.
The chip is showing signs of its age — the power audio amplifier no longer works correctly, but the output signal can still be amplified if driving a high impedance load.
Those are definitely the greatest rotary(?) switches I’ve laid eyes on – and you seldom see that classic label-gun anymore. You can hear samples of the box at work on Russ’ site.
The SN94281 is a simpler version of the SN76477 chip used for sound synthesis in many older arcade machines. Nowadays the chips are often sought out for use in homebrew synth designs such as Thomas Henry’s SN-Voice board.