Craig Anderton Tremolo

To say Craig Anderton's body of work is vast is probably an understatement. But within that body are several DIY classics, and this tremolo is no exception. This is a modified/updated version, specifically in the power section with a +/- 9v charge pump. The vactrol in the original is VTL5C1, but some combination of home rolled LDR/LED combo will probably work (you'll just have to experiment a bit). Schematic here. It'll be snug, but it should fit in a 1590B.