It seems a lot of the folks on this forum have played with the Ruby circuit, so I thought it was something I should build so I'd have that shared experience. I had every intention of following the schematic exactly, so I ordered some SMD J201s and the adapters. I'm sorry, but I had no idea how delicate a job that would be. I didn't even try. I had a bunch of LND150 MOSFETs around so I messed around on LTSpice with the Ruby Circuit and came up with something that looked like the buffer portion would have about the same amount of gain as Ruby, pretty close to unity. I breadboarded the amp and trialed the circuit using a small 6.5-inch woofer but I wasn't very impressed. The components sat on the breadboard for over a month and I was going to take it apart when I tried it with an old Chrylser 6x9 speaker. It sounded much better so I decided to throw together a case from scrap wood, mainly for the reason of actually completing something I started. As everyone knows, the ruby controls are very interactive. This means that when you dial in a sound you like, the volume is going to be fixed at that point. In my mind, it could use one more amplification stage but then you'd lose the simplicity and the ability to run off a 9-volt battery. It would also be like making a silk purse out of a sow's ear. At any rate, it's finished and it works. The DC supply is built from a multi-tap air conditioning control transformer. There's a 10 Ohm power resister between the filter caps to drop it down to around 16. I'm not sure the LND150 buffer would work well in a circuit powered by much less.