kilo-Hertz was sound-barrier territory even in the in the 1930s ;) E.g. Z1 was running at 1Hz, Z2 at 5Hz and Z3 at 5..10Hz. https://en.wikipedia.org/wiki/Z1_(

kilo-Hertz was sound-barrier territory even in the in the 1930s ;) E.g. Z1 was running at 1Hz, Z2 at 5Hz and Z3 at 5..10Hz. https://en.wikipedia.org/wiki/Z1_(computer) https://en.wikipedia.org/wiki/Z1_(computer) https://en.wikipedia.org/wiki/Z2_(computer) https://en.wikipedia.org/wiki/Z2_(computer) https://en.wikipedia.org/wiki/Z3_(computer) https://en.wikipedia.org/wiki/Z3_(computer)