The Multiplex is a tape-echo simulator, using two PT2399 delay lines. It has a momentary footswitch that does some subtle pitch bending (up while holding, down after you've let go) for a cool, unusual style of modulation. Josh McClarren at 1776 Effects did an especially fantastic job on the dry path and repeats filtering (progressive bass loss!), and I think it's the best PT2399 delay I've played. I highly recommend building one. (Pick up some of Josh's other projects and his 3PDT boards while you're at it -- all are well-designed.) I also get a little bit of the Rub-a-Dub Reverb (long brick) in near the end for some Space Echo shenanigans.
Gear used:
Don Quixotecaster (with Reilander Vintage Strat pickups)
Tone King Imperial (rhythm/blackface channel)
Multiplex
1776 Effects Multiplex
1776 Effects Rub-a-Dub Reverb
George L's, One Spot, and fingers.