>And they all use true class D PAs. Somehow most of the active CW stations do 
>not have a "clean"
>signal and those who have a clean signal are not QRV :-)

Hello Stefan,

with a class D PA key clicks are an issue when the drive signal is keyed. 
Soft-keying the PA itself will solve the problem.
If you have to key the drive signal I have the inmpression that a current mode 
class D PA behaves a bit better in regard with key-clicks (compared to voltage 
mode).

73, Rik  ON7YD - OR7T