I suppose the Why, is to be able to build something that is owned by its builder. That is, I know why I did these things, and I know its limits and strengths. So, with this knowlege and experience, I might discover a new way of doing IT( and I am *NOT* referring to that silly ebay ad, though cheap salvaged bits will be available there...:).

Let's pull back the curtain and reveal how easy it is to realize a good design. There is still blank space on the tube circuits canvas, waiting for motivated folks to pick up a pen or brush...

So, put a choke in place of a SS current regulating circuit. Remove or add a bypass capacitor ____, and see how it sounds. Some will turn out well and some will take up time in the lab. All of them will teach *SOMETHING* useful. If it is only to trust your own engineering, I'll be smiling...
cheers,
Douglas