After updating my nanoloop 1.6 cart, and putting shitwave in slot-A, I decided to load nanovoice into slot-B. I didn't have much luck, but that's a whole 'nother story. I'm here to post the links to both demo ROMs for your enjoyment.
To my knowledge, this version was never released as an official cartridge. It varies slightly from the version produced on cartridges (below) in that, while holding down A (after selecting a tone) and pressing left or, right, it generates a sequence of tones from highest to lowest. It's a feature I wish he'd included in the carts he produced a few years later.
This is the version released on official cartridges a few years back.