The Mad Blue Delay is a natural-sounding digital/analog delay, with the analog direct signal path. Inspired by the Deep Blue Delay by Mad Professor, this unit has about the same bandwidth as the classic tape echo units, and it can be used in front of an amplifier or amplifier effects loops.
Featuring an internal Feedback control trimmer, allowing you infinite repeats at the maximum setting.
The Mad Blue Delay is an easy delay project designed for all of the ones who are looking for a warmth analog-sounding delay.
Based on Mad professor’s famous Deep Blue Delay, this circuit has roots in one of the most famous delays in the DIY community, the Rebote by Tonepad, as many of the others pt2399 based delays nowadays. For this board’s development, we took hours analyzing both schematics and experimenting with different values to create the perfect ultimate Blue Delay.
This project is powered by a PT2399 digital delay chip through, but thanks to the analog signal path, it doesn’t have the sterile sound characteristics associated with modern digital delays but is instead much warmer and analog-voiced.
The direct signal path is short and made with analog amplifiers with no filtering. The echo signal has a tuned filtering to allow extreme settings without interference. There should be no distortion or tone coloration as long as the input level is in the range below the maximum allowed.
The delay is specially designed to work well with distorted tone, as this is the most critical application, where delays often fail.
Definitely the starting point for everyone who wants to jump into delays and modulation projects, and totally a must on your board!
For further analysis on this circuit take a look at this thread on Free Stomp Boxes Forum.
For any technical questions regarding this build don’t forget to check out our Facebook Group and our forum at Free Stomp Boxes.
Mad Blue Delay – Building Docs
Mad Blue Delay – Drilling Template
This is 3of3 my projects i did with PCB GM.
As i adore to manipulate with sound – i have immediately replaces a trim pot for feedback control – that is the feature i needed in proper delay/shoegaze machine.
One problem i have faced: pin 4 of PT2399 i had to connect additionally with ground (to avoid latching)- as assembled – effect passed a clean signal but (initially) did delayed. After this mod all works fine. Great delay machine.