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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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Tuesday, 29 January 2008

KLOWN Centaur

*UPDATE* For fully up to date schematics and layouts of the original Klon we, at freestompboxes.org, bought to reverse engineer please check out freestompboxes.org . Thanks to Soulsonic we have a great project on the way too :-)

Demo Video;

The KLON Centaur, one of the rarest and most sought after overdrive pedals currently available. With current production models costing in excess of $320 and ebay prices in the $500 range the Klon Centaur was a great candidate for reverse engineering. The schematic has been available for some time in closed circles but many are reluctant to share the information about the Klon Centaur freely until recently when a few guys got together and really made things happen. Great work and many thanks guys, you all know who you are!

So, what did I think of the Klon Centaur when I first saw the schematic? Well, it certainly isn't a tubescreamer or other common overdrive clone. It truly is an original circuit which utilizes some great ideas.

The Klon basically splits the signal into 3 parts - highs, mids and lows - the mid and low sections are "eq"ed and the highs are run through an overdrive circuit before the three parts are mixed back together again with an opamp mixer section - which is run off a charge pump supplying a dual polarity supply to stop any further clipping taking place. As the gain is increased the level of mids and lows present in the final mix is reduced, this is controlled via a dual taper pot which simultaneously increases the overdrive gain and reduces the level of the mid and low sections. The tone control is an active treble boost/cut allowing the level of the highs to be adjusted to taste.

Here you can see the copper clad PCB board after I printed the PCB trace onto "glossy" paper (Taken from a magazine I found lying around!) using a laser toner printer. I then ironed the print out onto the copper board until it was firmly stuck down. Next I soaked PCB board with attached paper in water until I could easily rub the paper away with my finger. As you can see this leaves the PCB trace attached to the copper board.

Here is the PCB before it is trimmed down and placed in the Ferric Chloride etching solution. You can see some small fills that I made with a permanent marker.

Here's the PCB in the Ferric Chloride. Etching away! This can take from 15 minutes to an hour, depending on the strength and temperature of the etching solution.

The finished PCB, cleaned with steel wool, trimmed and drilled. Now it's ready for population!

The PCB being populated. I need a box to put this thing in. I wonder what it should look like?

A nice Hammond BB Sized enclosure - marked out and drilled. It looks boring - I need some graphics!

I applied the graphics in the same way that I did the PCB toner transfer. Here it is ironed on and soaking through ready for the glossy paper to be removed.

Here's the enclosure with the graphic applied. A nice centaur image - just to keep the theme going!

So, enclosure drilled, graphics applied, PCB etched and populated and wiring done. I've got myself a Klon Centaur! See the finished unit below :-)

For your comparison here are some images of a real Klon Centaur. I really do like the look of these things. Nice and simple!

So there you have it. A DIY construction of the rare and famous Klon Centaur Overdrive. How does it sound? Just like a real Klon Centaur, nice booster - OK overdrive. I think to be a really great booster and overdrive it needs a few mods. In the near future I will be constructing my own version of the Klon circuit with these mods:

  • Separate Gain and Blend pots (The original uses a "dual ganged" pot instead of two individual pots to control the mix of clean signal and overdriven signal.
  • Improve the overdrive circuit - that overdrive section could easily be made to sound a little sweeter and a little less "thin" - this is a complaint which I have heard from many Klon Centaur users.
  • Diode blend pot - to allow you to blend between two distinct overdrive sounds. It just increases the versatility of the original unit.
  • Use a different OPAMP for the buffer/overdrive section. Why use that TL072 for the overdrive section? Why, why, why? I've been using a LF353 and it sounds better already! True Bypass?
The schematic below was produced by fully reverse engineering a true Klon, that we bought at freestompboxes and then butchered (By our very own Soulsonic)...

Here's a vero layout;

Here is Madbean's great project (schematic and PCB layout): http://www.madbeanpedals.com/projects/Sunking/docs/Sunking_ver.3.pdf
I've built quite a few from this layout and they sound great.

For more info on this project or to buy one of the 100,000 Klown Centaur pedals I have since made please email me. You can find my address at the top of the page... Again; thanks to everyone who has made this build possible - you know who you are, especially MM and MC ;-)


  1. This so cool that you've got these up and running that I'll gladly buy yer versh instead of building it.
    I mean I've never heard the "other" one so why not let you give me your impression and I'll eventually be able to compare the two.
    I appreciate the work you share so freely, Noel Grassy.

  2. great work here, those mods seem like they'd accompany the klown beautifully...do you think you could post a pcb or perfboard layout for the klown...that would be much appreciated.

  3. Hi there Erik. Check out freestompboxes.org for vero/pcb layouts for both the SOCJOD and klon and many others. I would strongly recommend "bajamans" mini klon project, that is what my klowns are based upon with just a few component changes. The values in bajamans pcb layout are identical to an original klon. For the SOCJOD pedal check out deaj's post on the CJOD lite, there is a pcb layout for it there, that circuit is almost identical to what I came up with for my design....

  4. Noel - I'll be doing a new version soon. I've been playing with a circuit we got from a fully reversed Klon (If anyone remembers when this thing started on FSB.org, we bought a new Klon to disembowl - we've finally done it!) Sounds great :-)

  5. Briggs, That's great news! I wondered what became of that pedal you guys bought.
    Keep me informed when you start building the new version. I'll gladly pre-pay you or whatever way you'ld like to work it.
    TIA, Noel Grassy

  6. Hey, great work! Still curious about the sound difference between the two. By the way, you wouldn't mind mailing me your PCB trace? (benjamin.niklasson@hotmail.com)


  7. Hi there ben. Check out freestompboxes.org for a fully upto date version of the PCB layout and scheme :-) It's in the K.L.O.N.E.D section.

  8. looks great... Just an idea for extra mods - to do a dual klon, so that one can be like a booster type?

  9. Hey buddy, love what your doing here...

    Ive been toying with getting one of these for years, but the price has always put me off, i'm definatley interested. I sent you an email but I dont think it got through...

    Please hit me up i'd love to have one...



  11. Do you still sell your version of the Klon pedal? I would like to purchase one if you do. Thanks.

  12. Do you still sell your version of the Klon pedal? I would like to purchase one if you do. Thanks.

  13. Clone all you like, but in the end,
    the old saying still holds true:
    "Imitation is the highest form of

    Rock on Mr. Finigan!


  14. When it comes to pesimists who think it is wrong to recreate the wheel and pass along knowledge to young up and comers who hopefully keep the music industry energetic and excited about something new or old recreated it must be because their lives are in the bottle or pipe or they are recovering from it and life sucks to be them. I for one beleive in my heart 100% whats happening here is a gift, I started hanging out at the music store when I was 6 years old and the amp tech there at the time was the guy that worked at Baggies recording studio with Hendrix and was a pioneer audiophile engineer for what todays industry is all about and it fascinated me and its why I still am at it. A soldering iron, a lamp, and my bench, nobody but god can tell me that what I do there is wrong. Amps, guitars, effects, speakers, ect. Obviously the prick whos whining has no talent, or may'be he's a Lawyer? or should have been. Anyway if you do not like what go's on here then go where you are wanted. This is a place where the Monks of the industry pray together. Sincerely, Big B

  15. I think it is perfectly good to clone, he should up his game and make the Klon better. If it was me Id be reading the forums for things I hadnt thought about, possibly done a Klon 2 with mods.

    And the sand cast enclosure is just pointless and over engineered. Its the sound that counts!!! If he's that good of a design engineer and market savvy I agree a larger range of fx pedals should have been made and a sensible price put on them. All he is doing by its scarsity is providing a means for people to profiteer.

    Foolish even if he is a purist!

  16. Well I think that the only way it would not be OK to clone something is if the designer has a patent. It could make the selling of such item actually illegal; now, if Joe-Schmoe wanted to just open it up, make some clones and "gift" them to friends, that is a different story. In the life time of the patent, either the patent holder officially licenses the circuit design for a cut, or gives his blessing for copies to be made, at which point the patent would become really irrelevant anyhow. IMHO, the designer and builder should be responsible for protecting his/her own intellectual property.

  17. Did you ever work out a modded version of your Super Klown?

  18. Hi! Nice work!
    Why does it have to he 7660CPA? I didn't understand if it was some joke or real matters.

  19. fwiw, i'm grateful for the knowledge gained messing with this circuit. i don't believe cloning something for personal use is wrong...particularly something out of production.
    that said, i didn't stick strictly to the project when i built it, took some libertys with values, and made something based on the most excellent pedal devised by mr. finnigan, but different. can i call it a klon? nope. it is what it is..based on it, but not an original. i am as grateful to bill as i am the guys at fsb (and other places that had also done the same thing...great minds)for the opportunity to see, build, and ultimately understand a truly unique circuit. if the day ever comes where i can afford an original, i would contact klon directly, not pay some inflated ebay hyped price...i've seen them with "buy it nows" approaching 2 grande!!!! is this ethical? do these scumbags selling shit this high give bill any money? apples and oranges in the end i think. it's a great device, perfect for somethings, lame for some others, but intrinsically cool to check out. that said...thanks to all.

  20. Great work. Is there a soure where I can buy all the components as a package for Klown Version 3 ?


  21. Hello! Any chance you would sell me a PCB? I have no way to etch in my tiny apartment ;(


  22. This comment has been removed by the author.

  23. Why not TL072? What don't you like about in a drive circuit?

  24. I know it has been about 18 years since the last original post but, does this klon still exist or available? Tkx

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