Is the Danelectro reverb unit one of those 'spring line' units? I recall that reverb used to be produced using a spring mounted inside a box, with a transponder at one end and a pick-up attached to a loop in the spring near the opposite end. I believe reverb could be adjusted by selecting different pickups attached to different loops. Made a racket if you dropped the unit while it was connected! Better leave it in the attic.

Mike