Welcome to the Revolution

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, 2 March 2009

Fred Briggs - Hummingbird Overdrive

I've been working on this pedal for around two months now. From conception to completion it is the longest I've ever spent on a stompbox project. I think it's paid off. Prepare yourself for some "mojo" chatter, here it goes -

The original idea was to create something a little like the BJF Honeybee Overdrive - a slew rate limited overdrive pedal which produces lovely soft overdrive tones (Slew rate is the rate at which a device can react to changes in a signal's amplitude - if you limit the slew rate the audible effect is a softening of the higher frequencies). Unlike the Honeybee though I wanted to keep the highend of my signal intact, unlike the roll off produced when you "dig in" to the Honeybee (created by what I believe is a feedback capacitor from diodes that clip to ground to the - input of an op amp chip, confirmation will be coming VERY shortly :-).

I started out looking at how slew rate limiting was achieved. Mostly it involved the use of an op amp chip such as the LM301 or CA3130 (Keep this chip in your head - I'm sure we'll be seeing more of it in the very near future! ;-) and an external compensation capacitor. I didn't want to use a chip in my design so I decided to go discrete! I started by taking the discrete op amp circuit from the boss blues driver circuit, well know for it's dynamic response to playing styles. This was my starting block. From there I made significant circuit modifications, firstly to induce considerable slewrate limiting and secondly to create a soft, dynamic overdrive that can be stacked very nicely with other gain pedals. After I had my basic sound I then fine tuned each individual section of the build, hand selected parts and tuned values to their optimum tonal values. I settled on a mixture of Metal Film and Carbon Composition resistors with a combination of Paper in Oil, Silver Mica, Metal Film and Tantalum capacitors. 

This rampant, unaffected parts selection ended up with a bill that was not too cheap but definitely worth it; this is, without a doubt, my favorite overdrive pedal. It is as dynamic as the Fulltone OCD while being much softer and playable at higher volumes. The high end is tamed and efficient, it'll still be there even with the gain maxed and volume low and it's always soft and syrupy with a chewy texture that allows notes to melt out from the fretboard. The "Nectar" control I incorporated allows a steady increase in low-end response meaning that you can lower the bass content for bass heavy amps while paying through humbuckers or twin the Hummingbird with brighter, single coil equipped guitars such as the telecaster without any compromise in playability.

I'm so happy with this design that I'm building myself another - the Hummingbird De-Luxe with two extra controls for "Sag" (Which you can see on the gut shot as a small black trim pot) and "Shimmer" (A treble boost/cut control). Check out the shots below!


  1. Hi! Sounds like a very cool pedal. Can you post the schematics?

  2. Cheers, the initial schematic is over at freestompboxes.org, I need to make some revisions before I post it up here :-)

  3. Thanks for the fast reply. Please post a comment when you are finished.

  4. What Is the finish on that pedal? What type of paint?

  5. It's Gold Hammerite base with black and white enamel over the top plus a layer of clear laquer. It takes about a week to cure but it's tough as hell once it's done.

  6. HI:

    Amazing job!
    can you send me the schematic of LONDON FUZZ please...

    My mail is:

    I very much appreciate that..


  7. Amazing! Do you plan on selling PCB's of this project?

  8. Hey Fred, the way you describe this pedal makes it sound pretty cool.

    I got a question for ya, because I know you've tried out a few more designs than I have. I'm looking for a "JTM/Plexi on 5" sound (i.e., Angus's sound on ACDC's latest two albums, Stiff Upper Lip or Black Ice), but people only seem to want to design "Plexi on 10" pedals. Any suggestions for designs I might want to check out?

  9. Hi Fred,

    Dude, your site has been an inspiration for a lot of my builds (Eternity, Klon, etc). Haven't designed anything original yet, but I'll get around to that.

    I would be so obliged if you will post a revised version of this Hummingbird, preferably with the exact parts you used - seems a lot of the stuff you have on there looks somewhat exotic. Please.

    Thank you very much!


Comments are welcome on Revolution Deux. However, please do not spam links to unrelated sites - these comments will be removed! Thanks - Briggs.