Sombrerero

Hi! Sorry if this was posted elsewhere but I really cant find it anywhere. Which are de specs of the headphone out of the Toneport Ux1? Y found the recomendations for headphones are between 150 and 600 Ohm but which is the actual impedance of the headphone out itself? I find tonal variations between this and other sources when using low impedance headphones (32 or lower) and I suspect is related to this and maybe is really high. Thanks!