The Rust Rod emulates the sludgy sustain of a circa 1973-4 rams head (and I apologize that the only clip posted is by the Gilmourish guy who can make anything sound like Gilmour, really). The General Pig emulates the cutting transparency of a circa 1976 rams head (aka the "Gilmour" sound as heard on both Animals, played with a Tele, and The Wall, played with a Strat). Previously, the closest I've gotten to this sound was with my Giant Meat Pie BC239 edition, which required the use of tropical fish capacitors (to round out the thin tone of those transistors). So you can understand my excitement that I managed to get very nearly the same effect by merely changing out the transistor in my Mayo circuit (using multilayer ceramic capacitors) and modding its tone stack to the 1976 spec. The new transistor is clear but not as thin sounding as a BC239, and its gain is right down the middle of what a vintage BMP circuit likes to see. So zero extra filtering or negative feedback was required to get "that" sound, making it more transparent and less "processed" sounding than the P19. Which is precisely why I retired the P19 in favor of this new model.