Nice link. These guys make great tanks: >In the spring tank there is a second transducer at the opposite end of the spring that you can think of as the ear in

Nice link. These guys make great tanks: >In the spring tank there is a second transducer at the opposite end of the spring that you can think of as the ear in a room. Instead of a signal coming in to manipulate the springs through this transducer, it works in the exact opposite way. The wave passed through the spring from the first transducer affects the magnet suspended in the gap of the second transducer. The moving field of this magnet interacts with the coil of the transducer to create an electric signal that is carried through the wires to the RCA jack labeled OUT. Not much differently than a magnetic guitar pickup or a crankshaft position sensor which are all properly included as Hall sensors. Interestingly, the reverb input transducer is the one acting like a solenoid and the output transducer is employed as the Hall sensor. And I'm sure you see how both transducers are built very similarly and look almost identical. Different impedances in the windings of their coils though.