PT Delay

PT Delay is our very own design in a compact 125B enclosure. We've designed it specifically to teach beginner soldering workshops. It's easy to build and sounds delightful!

If you would like to do one of our workshops, check out this page: Upcoming Workshops

The pedal goes all the way from clean, reverb-like slapback to noisy and crunchy repeats on longer time setting. The mix knob range is full dry to full wet. It does not self-oscillate when running regular level signals into it, but can be pushed over the edge by putting an overdrive or compressor in front.

PT Delay is based on a ubiquitous lo-fi delay chip originally designed for karaoke systems by Princeton Technology Corp. That chip is a strange beast. It is digital in nature, but it's not a microcontroller, not something you can program. It's designed to do one thing only: sample the incoming signal, store the samples on chip and reproduce them after some time.

Download the schematic here

The core of the pedal (Sheet 2 "pt" of the schematic) is an echo circuit from the PT2399 datasheet with just a few values changed. The current sink and the anti-latchup circuits are taken from the fantastic article by Electrosmash. The input signal goes through an opamp-based buffer into both the delay core and the mix circuit (Sheet 3 "io").