Thursday, 21 February 2013

Rotary Speaker mkII

This is my new improved rotary speaker - with foot pedal speed control. The foot control simply turns a potentiometer that's connected to a PWM circuit driving the motor speed.

This approach is similar to the treble horn of a Leslie speaker.

Rotary Speaker mkII

A piece of PVC duct pipe bend is rotated above the speaker. There's a paper cup (with bottom removed) wedged into the pipe to give more 'fling' to the sound.

early test

Here's what's inside - a motor and belt which are enclosed in the box. You can see the speaker below.

Rotary Speaker motor box

Foot Controller.

foot controller mechanism

This is the mechanism in prototype.

foot control construction

And the finished pedal.

foot controller

As usual I'm using a Ruby amp to drive the speaker:

Here's a video of it in action with guitar and then keyboards -no other effects.


  1. you have inspired me to build one similar.

  2. I'm trying to build a DIY MIDI expression pedal, where can I find the parts for the pedal part of this?