I've used the Kora Design 30 amp and found it to have strengths and weaknesses.
The triode tube Kora is very transparent, has a midrange that is full-bodied, palpable and 3-D.The bass of the Kora is respectable for a tube amplifier and the sonic presentation exhibited by this French amp is so gentle that it lends itself to consecutive hours of listening.Conversely, the Design 30 does have some faults; the dynamic range is significantly limited (i.e. compressed) and the tempo of music is noticeable slowed. If your musical taste is fast tempo music that is wrought with dynamic swing,then the Kora will bore you.However, if you're a fan of Bach funeral marches, then the Design 30 will engulf your ears in a sea of rich harmonic texture (the Kora is really wonderful for this type of music).Overall, the Design 30 is a great amp!!