In the early Tangerine Dream albums, well not the really early ones, but the ones from the first half of the 1980’, I saw a reference to a device called Roland SDD-320 or Dimension-D.
This device is basically a very rich and warm chorus effect that creates a unique spatial effect like no other, subtle yet rich and distinct.
Lately I saw a PCB design by a person by the name of Jurgen Haible that essentially recreates the same effect. The project name is “Subtle Chorus” and more details can be found here.
My implementation is a double Dim-D (2 PCBs behind a single faceplate) and since the board is populated, it should be finished very soon.