In article , says...

First one I've come across, anyone know what is inside? too big to be
bucket-brigade and regulator and a couple of opamps.
i don;t believe this supposed schematic
http://blogs.yahoo.co.jp/clubman501/60421206.html
7 pins to the outside world and pic is correct of this "Digi-log reverb"

I have a vague recollection of coming across a reverb unit in the 1970s
which had one of more long springs inside. Worked a bit like those
ancient mercury delay line computer stores. It was certainly big!

Mike.