Introduction

This circuit is my take on a delay unit based on the PT2399 chip.

The circuit

There are only some minor tweaks to the schematic from the datasheet, first of all I lowered the 100nF capacitors in the Delta Encoders and Decoders, this gives the unit a higer bandwidth. So I also had to change the filters to accomodate for that. At longer delay settings the circuit might therefore have somewhat more noise, while at shorter settings it has more bandwidth. Since I didn't like the clipping of the chip, and to make the response more like an analog (tape) delay I added a softclipper before the digital delay core. So the delay allows going softly into selfregeneration, with feedback even stronger than 1. The pots permit setting the amount of regeneration and the relative amplitudes of the dry and delayed signal.