First of all, apologies for the multiple-part question. I don't know if that's allowed. Anyway: This is the power supply for the following amplifier circuit: I've circled all of the parts which I'm confused about, which, unfortunately is most of it. Is such a complicated power supply really necessary? My assumption is that the green section is the power supply for the tube heaters, and the blue section is for supplying power to the tube cathodes? The first part of the question: Look at the red section. Is that a 3-way transformer? What does that mean? Is some voltage being taken off at one of the secondary coils, and a different amount taken off at the other secondary? Are they both called secondary here? How would I make such a transformer? The second part: Look at the blue section. What on earth could all these passive components be doing? Why not just have one capacitor? They're for filtering the signal, right? To get a flatter DC signal from the AC input? The third part: How's that LM338K working? It just looks like a jumble of components scattered around it. The last part: I want to make a tube amp, I'm not interested in making a power supply. Is there any way to buy a component which essentially is one of these power supplies?