For a plate reverb the secret sauce is matching a speaker driver (the hardware that is) to the plate material. Some are too weak, some too forceful.
I see no reason why the Doepfer circuit wouldn’t work though you will need to up the gain to get the signal moving. The fun part is matching the signal to the combination of the speaker driver and the mass and resonance of the plate. For the return a piezoelectric pickup works almost as well as a stripped down speaker as a microphone.
There are several dedicated drivers (the speaker hardware) out there being punted for flat speaker systems that are just ridiculously over priced. As I’m old school I’ll be down the scrapyard to hustle a few car stereo speakers; remove the paper cone and you have reasonable driver. For the proof of concept set up I mentioned the driver was just hot glued to the sheet. I took a metal frame I was given by a pal which was the transport frame for his new washing machine and tried suspending different sheet materials to see the effect. In some cases I put the metal sheets under surface tension (beating out the surface with a hammer much like a guitar resonator or older cymbals.
The one I’m looking forward to play with is using a pane of double glazing as glass has a number of frequency sweet spots, though some frequency/amplitude combos may shatter the pane which is cool.
One reverb id like to play with is a design using a laser as the pick-up, much like a galvanometer, to add the sheet movement to the original sound. The displacement of the sheet is an analogue to the reverb effect.
A DIY plate reverb won’t ever match the quality of the big studios systems but I guarantee no other musician will have the individual nuance of your own plate. I know many producers that swear by some seriously hinky kit for ‘their sound’ and refuse to use other gear.
I have yet to make a final version for myself but I’ve been part of a few DIY reverb projects for producer friends. I think I mentioned a couple on the forum here.
And the to-do pile it ever grows.