Here is a very interesting and not overly complicated PT2399 based circuit from Bluff Chill Devices. It is an "envelope modulated delay" which sort of emulates a worn out tape delay.
This layout is for V1 only but there is two layouts; one for stock 2 knob version and one modified 4 knob version. See details for the latter further down of this post
First up the schematic and a writeup about possible mods at the Bluff Chill blog.
And the modified version with added Mix and Realese controls. Note that pot values and lug connections isn't mentioned in the blog post so some tweaking is necessary to get satisfying results. I added the values that "should" work...
*Edit* Jordan verified the modified layout bellow and tested pot values and tapers.
Later versions also had a feedback control and an improved blend circuit but there is no schematic avaiable for it on the web...
