I just posted with a somewhat similar question. Although I haven't tried the K4, I would suspect that having the left and right speakers so close together in one cabinet wouldn't allow adequate separation to get a good stereo image. I tried one of Roland's earlier stereo keyboard amps and didn't think it did a very good job.

But the K4 is a Traynor, so perhaps their design expertise would make a difference. IF it were to work properly, I suspect you'd need to center the amp directly behind your head, or in front, so that each ear hears one side of the stereo image. My two cents.

Michael

Has anybody tried K4 with acoustic piano sound (PTQ or any other)? It's giving some kind of stereo image which is crucial with acoustic piano sounds.

Few years ago I tested some of those keyboard amps like Roland KC-series, but they were terrible... Is K4 any better on stage? Right now I'm using two TC Helicon's VSM 300 XTs which are mainly made for singers but I like them with piano monitoring (they are small and powerful, but of course you need two to make it stereo).

One more thing I'm curious is the placing of those keyboard amps. Where to put it (K4 for example) to make it sound as good as possible...?