Old School Spring Reverb.

  • Based on a circuit from Ray Wilson and MFOS
  • Fully analog reverb, with CV attenuation of the input signal
  • +/- 12VDC operation

The spring reverb has been around since late 1939 when Laurens Hammond first Patented it. In the 1940s they were used by foley artists on the radio and installed into almost every Hammond organ to provide reverberation effects and give the organ an ‘echo’ or  concert hall effect. They are extremely simple to build, but hard to control and minimize distortion.  Basically, you take a long spring, place a transducer at one end, (the input), and an electric or magnetic pickup at the other (the output). The signal passing through the spring causing it to vibrate and produce additional, but delayed near copies of the signal. Most echo effects or reverb units are digital by nature and many guitar effects pedal use the PT2399 integrated circuit to do this.

This is one of Ray Wilson’s last designs he was working on when he became ill so there is not a Printed Circuit Board (PCB) available for this circuit. You can visit Ray’s site HERE to get more information in building one. I built mine out of scrap wood laying around. The basic idea is it just hangs on the wall and you can plug in CV and signals from your modular or portable synth to obtain the desired effects.


Here are images of the build:

  • SR-6
  • SR-2
  • SR-4
  • SR-7