Don & Paul,

Almost all mic-inputs are 'low impedance' these days and I expect the 6.3mm jack-inputs to be UNbalanced.
I agree with Don saying the 6.3mm jack is toyish and not a good connector for mic-signals :
The tip, ring and housing get dirty because people touch the metal parts......(salty body fluids etc) and this causes signal loss / bad contacts.

I prefer hiQ XLR's with goldplated-contacts AND a 'lock' mechanism to keep it in place.
The contacts are hard to touch because they are protected by the XLR body.

The PRO and SD1 both have XLR inputs but I'm not 100% sure they are BALANCED inputs.
(XLR's are no guarantee for this)

Roel