Build an experimental echo pedal

!ATTENTION!
I have made some changes to the schematic I posted this morning. The schematic posted below reflects these changes.
-C1 has been assigned a value of 47uF
-R19 has been removed.
-An unmarked resistor at pin 5 of the op amp has been removed.

This crazy echo circuit is the design I’ve been using in my EchoBender pedal. Check out some videos of the circuit in action.

The heart of this circuit is the PT2399 echo IC. View the data sheet here. They can be found pretty cheaply from various distributors.

The fun starts when you push the IC beyond it’s intended parameters. Drastically lowering the pitch uncovers digital noise and strange blipping effects. I’ve also included a fun audio feedback feature which can be used to create intense distortion as well as interesting octave and pitch tracking effects.

Thanks to Dan Wagoner for sending in a parts list!

More:

Collin’s Lab: Guitar pedal modding with Arduino