I bought my K4 for use with keyboards as one of several configurations of Sound Reinforcement systems. I've used it alone and with two powered 8" monitors on the wing (it facillitates this very nicely in case you need more coverage). Since I quit gigging, I use it for my E-drum kit (DM10 Pro) where it sounds terrific. The guitarist that I most often work with absolutely loves it and thinks it works extremely well as a guitar amp (he loves the sound with the tube channel).

I'm not promoting it as an 'end all' solution for keyboard amplification as I personally prefer my SXa250 powered 15's. On gigs I always used an organ/Leslie (3300) combo so I'm mostly talking rehearsal and practice with the other sound stuff. Still, the K4 is a largly unknown, unhearlded little Jewell IMO. Heavy as hell but sounds great.

chas