Distortion vs impedance

[Natural Sound]

Quick question. I was wondering what happens to distortion vs impedance. For argument sake let's use the S.E.X. Amp as an example with high impedance headphones around 300 ohm. What happens to distortion when using the output transformers wired for 8 ohm vs 32 ohm?

 

[Doc B]

If you were asking 8 ohms vs 300 ohms output impedance there would be a slight increase in distortion at higher volume at the 300 ohms setting vs the 8 ohm setting, and probably a sense of fuller bass at the 300 ohm setting. With 300 ohm cans the difference between 8 ohms and 32 ohms output impedance will be pretty tiny with respect to perceived distortion levels. But where the 8 ohm setting will shine is in having a better S/N ratio and a more quiet noise floor for a given listening level compared to the 32 ohm setting.