The Reverb 35B uses a large 17 inch 3 spring Accutronics tank with long 3 second decay. The Wet/dry mix is voltage controlled using a dual low noise VCA cross-fader circuit. A wet only output is available for pseudo stereo effects. An additional feed back control feeds the reverb signal back into itself for longer decay and weird drone effects.

http://modcan.com/bmodules/reverb.html