This isn’t really related to the Optigan, but it’s a fascinating article folks might find interesting. The Birotron was a cheaper version of the Melotron, only instead of tape banks, the Birotron used 8-track tapes. The last part of the story turns sad though, when the author reveals the frightening financial state that had befallen the inventor, Dave Biro.

Ker-Chunk! — A Hit-Making Keyboard Made of 8-Track Car Stereos? Meet Rock’s Rarest Instrument
The Believer (June/July, 2007)
http://www.believermag.com