Yes, thats right. The TS-23 uses TUBES, not transistors. It is the worlds first tube voltage-controlled oscillator. It uses two thyratron tubes, giving two VCO pitches simultaneously. Range is approximately 4 octaves, following a V/Hz control voltage response.
TS-23 is compatible with all existing solid-state analog synthesizers. This circuit gives a unique waveform--a distorted exponential sawtooth, unique to thyratron tubes and reminiscent of the vintage (and rare) Mixturtrautonium electronic instrument of the 1930s.
And, the TS-23 contains a 6BN6 tube acting as a waveform clipper. This obscure and special tube was used in FM radios as a detector. Its highly nonlinear characteristic gives a very soft wave clipping effect, which is unique in electronics, previously unknown in audio design, and not available in software simulators or in solid-state devices.