Several years ago I received a telephone call from a man named Johan VanLeer. VanLeer designed reverb systems for Hammond many many decades ago, and later developed a very rare spring system for Quad Eight. He sent me some interesting information regard the Quad Eight system; click here to read that earlier post. VanLeer is still developing new spring reverb approaches to-this-day. Here is a bit of of info on his latest project.
“Still tinkering with spring (4) reverberation systems, I thought updating you. Due to the 17″ rack width dimensions, the DELAY TIME is limited to the spring length, which has to be less than about 13”.
To double the DELAY TIME I constructed a few systems by using and updating the 1964 US Patent No: 3,159,713 by W.C. (Bill) Laube, Jr., like me, a Hammond Organ Co. Engineer.
In the so called “single ended system” both the receive- and send transducer are on the same side and the other side has the spring-ends firmly anchored.
So, the send-signal bounces back doubling the delay time before it reaches the receiving transducer.
To avoid cross-talk from the sender (1 coil), the 2 coils of the receiving transducer are connected out-off-phase.