[Elecraft] CW-Pitch 600 Hz or 700 Hz or what?

[Karsten Eppert(DK4AS)]

Hi everybody,
my K2 is #4764.
I am in doubt about the optimum CW-pitch. I think I remember from the 
old days, that the human ear has the best "built in" filter around 1000 
Hz, so I thought, CW-crystal filters should have a pitch around 1000 Hz. 
Many commercial units seem to have 800 Hz, the standard K2 has a 
suggested pitch of 600 Hz.

1. why is that so?

2. I have set my K2 to 700 Hz but live with the very personal (not 
supported by spectrogram) impression that the overall 
selectivity-response is broader than it could be. Is it possible, that 
the NF-path is optimised for a 600 Hz-response? If so, I would go 
through the entire re-alignement procedure and reset everything to 600 
Hz. Or is it all stupid personal impression?
73
Karsten