iternabe NV10S and NV12 has the grand action. That would be #1 reason for me to pick over K500.
... so it's only handicap is the upright action..
You addressed a very good point: Upright vs Grand action:
AFAIK, the grand action provides double escapement, while the upright does not. I am not sure, but actually a grand action should be easier to construct than an upright action, because the physics move the hammer weight very naturally away from the strings (after the hammer hit). On an upright, there is more mechanical overhead needed to compensate for that.
But because the grand action could have a simpler design, there is also room for more improvements like the double escapement. Something that is too complicated/expensive/errorprone for an upright.
Is my theory correct, why a grand features double escapement while an upright doesn't?
Or are there exceptions out there (upright with double escapement / grand without)?
And how exactly does a grand action play different to an upright? Is this only the repetition speed? Or is there more, like the option to retrigger a key again, without the need to release it completely? (Retrigger while dampers are lifted)
And how does an upright action compares to a good digital? Like NV5 vs CA901 – does the CA901 have the same advantages over the NV5 like a grand has? (But also feel less real than the NV5, on the other hand)
