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Hi there, welcome to my blog - La Revolution Deux. It's an odd name - but I like it! Here you will find all the info on my various DIY Guitar effects builds, amplifiers and guitars. Everything from a humble Ibanez tubescreamer to the holiest KLON Overdrive.

You may also find a few effects builds that I am looking to move on - usually in exchange for other effects/gear/cash. You can always check my ebay account to see what I've got up for grabs.

Have fun, enjoy the blog - Fred Briggs :-)


Feel free to get in contact with me about anything you see on this blog or with any general questions about guitars, amplifiers and effects, I'll be happy to answer! Just click the button above to email me directly or alternately my email address is fredbriggs2007 [at] googlemail [dot] com

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Monday, 9 January 2012

Mad Professor - Deep Blue Delay

Here is another Mad Professor pedal, one of the designs which has garnered the most interest around it. Well, it's been gutted and reverse engineered. Unfortunately there is nothing new in the design - it's a pretty standard PT2399 design based off the Rebote Delay 2.5 but it does sound very good.

Here is the schematic and project file (http://www.madbeanpedals.com)

Here is the ProGuitarShop youtube demo of the Deep Blue Delay;

If you fancy a challenge here's a vero layout by Nocentelli, go on - have a pop!

Here is the thread at freestompboxes.org - http://www.freestompboxes.org/viewtopic.php?f=7&t=713


  1. If it is a pretty standard design but does sound very good, any idea what makes that standard design sound so good?

    1. It just works - the PT2399 is a decent delay chip, using the op amp buffers and some low pass filtering keeps the circuit simple yet functional; pretty much the basis of all decent sounding circuit designs..

    2. Is the low pass filtering you speak of occurring between pins 14 and 15 in the PT2399 feed back circuit? It's a little different than the data sheet example.

  2. Layout seems interesting (the transfer plate), but no information is tested. I saw that the four pin diagram shows a grounding pin 3 and the layout does not show it, but that the four pin connects directly to the delay, being open when the volume is turned down. You got to ride it to see if it works?

  3. Would it be difficult to add a tone knob for the delays? Or a switch between the default and a "darker" value? This would be my second build.

    Great site by the way! /J

    1. Methinks "Mix 3"? Cap-pot-ground is easy. Switch would be cap-switch-res-ground.

  4. how can i resize the pcb so i can print it?

  5. Hi.. I understand that with rpts on max it should oscilate, right? Here's what mine sounds like, with all the pots maxed out - https://dl.dropboxusercontent.com/u/1767893/seaurchindelaytest01.mp3
    it sounds overly dark and just not enough repeats and no oscillation.. thoughts?
    Any idea of which resistors I could change to fix it?

  6. I bread boarded it, and it didn't oscillate either.

  7. I made this pedal more so it works when I reset the shot and Pt 2399 can someone help me ?


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