Solid state amps have come a long way since the KSA series. If you want to keep it as your main amp, you are going to have to live with its limitations. You can try using other components that are known to be strong in the image/soundstage department, but it doesn't always work. Sometimes when you have a restrictive component in certain areas, it doesn't allow other components to do their job either.
A good example is my old Rowland 112. It has no depth. Nothing at all; its completely flat. I've tried all different kinds of components but I always get the same result, no depth. The odd thing is that I've spoken to other people who have the same amp and some of them have the same exact problem I have, and some don't. They have no idea what I'm talking about when I mention it.
I hope that helps some.
A good example is my old Rowland 112. It has no depth. Nothing at all; its completely flat. I've tried all different kinds of components but I always get the same result, no depth. The odd thing is that I've spoken to other people who have the same amp and some of them have the same exact problem I have, and some don't. They have no idea what I'm talking about when I mention it.
I hope that helps some.