Additive Synthesis Module
The tELHARMONIC is a Multi-Voice, Multi-Algorithm synthesizer module coded by Tom Erbe with the goal of presenting three historically important pioneering electronic music tone generation techniques less often implemented within the modular synthesizer.
The module is named for the music hall where the first Telharmonium concerts were held.
http://www.makenoisemusic.com/telharmonic.html
No info about availability.
$349