I think the actual chip used has a lot to do with it too. As time goes on, hobbyists are finding out which chips are preferred over other ones. Like the 3116, 3118, 7297 as opposed to the earlier 3886.
Check out the Fleawatts by Derek Sanderson. They sound amazing at a much lower cost than many others
Check out the Fleawatts by Derek Sanderson. They sound amazing at a much lower cost than many others