This layout is the legendary Klon Centaur, but without the charge pump. The charge pump is present in the original to keep the 2nd opamp from clipping. But since there are diodes before signal even reaches that IC, it may not matter. Check out this thread on FSB for more info and schematic. Without the charge pump, the circuit was much easier to layout for a smaller footprint. Still a fairly large board, but should still fit in a 1590B.
