Klipschorns are very difficult Loudspeakers because they have an impedence curve from 1-30 (!!) Ohm and are at the same time very sensitive with 104dB/W. I have tried a lot of different amps: class A, 300B tube SET amp, AB, JFET Mosfet etcetc. Finaly with the Purifi amps everything is knitted together and the KHorns really sing. They need timealignment and Dirac but these amps make all the difference. Really happy!
Audiophonics input board make it possible to bypass the opamps. Can't hear much difference though so that's also testament for a fine configuration. It is also dead silent.
BTW it is fascinating how many countries worked together to get this done. Start counting.