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Category: BBDs+Delays

Designing a Slapback Echo pedal

Posted on July 27, 2024February 19, 2025

I recently saw an advert for the new EHX Slapback Echo reissue pedal and thought it was a cool little thing and would make a nice project. The original pedal came out in 1978 and was about as simple as it could get. There was one “Blend” knob to mix the straight and delayed signal, and […]

Posted in BBDs+Delays, Projects, Stompbox stuff   7 Comments on Designing a Slapback Echo pedal

Two StompLFO projects: Mod Delay

Posted on August 5, 2022September 17, 2023

I’d like to share a couple of things I’ve had kicking around on my desk for a long while. The first one was a simple optical tremolo, and for this second StompLFO project, we’re going to use the StompLFO to apply modulation to a PT2399 delay. This is actually very simple to do! PTWobble, StompLFO […]

Posted in BBDs+Delays, Projects, Stompbox stuff, Uncategorized   7 Comments on Two StompLFO projects: Mod Delay

Building the Electric Druid pedals

Posted on November 20, 2019November 20, 2019

  This page collects together just the information you need if you’re intending to build one of the Electric Druid effects pedal/stompbox projects. For each pedal, you only really need the construction guide, which includes the full bill of materials (BOM) and a wiring diagram for the PCB in the enclosure. We also provide a […]

Posted in BBDs+Delays, Distortion, Overdrive, and Fuzz, Flanger, Stompbox stuff, Wah, Autowah, and Filters   Leave a Comment on Building the Electric Druid pedals

Digitech PDS-1550 Programmable Distortion pedal analysis

Posted on November 22, 2018October 5, 2020

The Digitech DOD PDS-1550 was a member of the 1980’s Digitech “Dual pedal” range. It’s a pretty weird thing, and that’s partly why I’d like to take a closer look at it here. During my analysis of this pedal, I’ve discovered its dirty secret. Let’s get one thing out of the way early on though […]

Posted in BBDs+Delays, Distortion, Overdrive, and Fuzz, Stompbox stuff   33 Comments on Digitech PDS-1550 Programmable Distortion pedal analysis

Flangelicious – A super-dooper flanger (Now in 2 versions!)

Posted on May 24, 2016July 14, 2021

Flangers are generally regarded as one of the most complicated pedals to build. A typical design has tons of chips and lots of circuit elements. Flangelicious isn’t like that. By using a microprocessor to generate an LFO-modulated clock signal directly, we can get rid of a lot of the non-signal path stuff and add features whilst we’re about it. […]

Posted in BBDs+Delays, Flanger, Projects, Stompbox stuff   130 Comments on Flangelicious – A super-dooper flanger (Now in 2 versions!)

DIY 4 Second Digital Delay

Posted on May 9, 2016June 4, 2017

Recently I’ve been working on a four second digital delay with tap tempo and delay trails. There are lots of digital delay projects already, but the vast majority of them are based on the PT2399, which limits both the length of the delay and the sound quality.   A quick summary of the features: 0 […]

Posted in BBDs+Delays, Projects, Stompbox stuff   262 Comments on DIY 4 Second Digital Delay

Noise Reduction with Companders

Posted on January 4, 2016January 18, 2016

What’s a “compander”? It’s a simple way to make your circuit quieter! So how does it work? Let’s say we’ve got a fairly noisy effect, like a BBD. The basic idea is that you make quiet signals louder before you put them through the effect, and then you make them quiet again after the effect, […]

Posted in BBDs+Delays, Chorus, Flanger, Projects, Stompbox stuff   21 Comments on Noise Reduction with Companders

Investigations into what a BBD Chorus unit *really* does

Posted on June 13, 2015October 31, 2018

I’ve been curious about Chorus for a while, since I’ve been working on and off with chorus design myself. There were a few things I didn’t understand, like what the relationshp is between the modulation LFO’s waveshape and the frequency modulation of signals going through the chorus. You’d think that if you use a sinewave […]

Posted in BBDs+Delays, Chorus, Flanger, Stompbox stuff, Synth DIY   18 Comments on Investigations into what a BBD Chorus unit *really* does

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Personal use

Druid code and schematics are released under a CC BY-NC-SA 4.0 license, so feel free to download and use Electric Druid code in your personal synth, pedal, or sonic blastertron 2000. Grab a copy of the schematics and tweak away to your heart’s content. If you don’t have a PIC programmer, you can order a chip from the shop. Check the legal stuff for more details.

Commercial use

Electric Druid code and schematics are released under a CC BY-NC-SA 4.0 license. Please check the legal stuff for more details. If you’d like to use Electric Druid chips, code, or circuits in your commercial product, we’d ask that you buy chips from us to help support the development of further projects. We can supply programmed, labelled chips in whatever quantities you need. If this isn’t suitable, please contact us to discuss your requirements. Thanks!