These are raw ideas, circuits with theory only, or ideas that have received little or no testing. In some cases (the SS OPT) testing was performed and the circuit was deemed “not ready for prime time” (it blew up a lot). If one of these circuits is developed further and thoroughly tested it will be moved to the Proven Circuits page. PowerDrive is an example of this, it began as a “Super Tube?” experiment. It worked so well that I have used it in many of my amplifier designs. Other people have used it with great success also.