Boy, I didn’t mean to kill this thread – I hope I haven’t, really. I’m surprised that no one has added any items.
In any event, to extend my hijack slightly – although there may not be any recordings of the Telharmonium, there is one of a competitor and relative, the Choralcelo, which was also huge (but not as big), and which apparently used sine wheels to electro-mechanically generate its tones.
I’m disappointed. With all that awesome synthetic capability you’d think that they would have created new and interesting waveforms, a la the Moog. But the Choralcelo sounds disappointingly like an ordinary organ:
