Generally thought to be the first electronic music instrument, the first Telharmonium was built by Thaddeus Cahill in 1897. The instrument was conceptually similar to, although much more complex than, a Hammond organ. It used a bank of tone generators, which probably output a waveform close to but not quite a sine wave, and a set of mixing controls to synthesize different waveforms; as such, it can be considered an additive synthesis instrument. Note that at the time, de Forest had yet to invent the triode tube, and so there was no such thing as an audio amplifer. That meant that the Telharmonium's tone generators had to generate enough power for the waveform to drive a loudspeaker directly. As a result, the tone generators were in fact high-voltage electrical generators, geared to run at