Here’s an interesting and fairly simple noise gate circuit sent to me by Stanik Nupel from a Polish electronics book. Schematic and Stanik’s original layout can be found here. The switch isn’t in his original layout, so it may not be all that necessary. It’ll be a tight squeeze in a 1590B, but should fit especially if you’re using low profile jacks. Otherwise it’ll fit nicely in a 125B with top mounted jacks.
