Trogotronic has you covered. The sounds from these units are fairly interesting, but I am not really sure as to how the the tubes are used. My guess in some unorthodox way, however I am confident this builder knows what they are doing granted they built a huge Tube Mixer for themselves. I will say that the sounds are different from just a basic 555 oscillator, but they are similar none to less. Also these units must use low power tubes because the cases would never fit an entire power stage safely. The blue joystick box is apparently a switcher for patching signals in and out based on the direction of the stick. [Thanks to Housepig for the link]