In my experience, keyboard amp will not work. I had a Roland xxx300? Keyboard amp. Killer amp but just did not sound like my bass amps. Just did not have big enough sound. It was loud, but struggled compared to my bass amps.
IMHO...A KC300 should work fine for bass. Whether you like the sound or not is another matter. I do, and you don't.
@Hogman99 Since you already have a keyboard amp, IMHO give it a try and judge for yourself.
