Klon Centaur

Here’s a layout I did for the Klon Centaur overdrive based on a schematic by soulsonic.

Update (28.02.2011): I finally got around to boxing the Centaur. This time I felt brave and decided to try an artwork technique courtesy of “frequencycentral” over at freestompboxes.org (described in this thread). I thought I gave it a good go being the first time and all, but needless to say from looking at the picture my only option was to leave it to dry outside in -20 degrees Celsius (that’s -4F for you Americans) and the result was less than optimal. Looking forward to spring and my next attempt.

Update (18.03.2012): I’ve had several requests for voltage readings from my build and here goes:

Battery at approx. +8.90v and all pots at zero.

1  +4.43V  +4.6V  +8.84V
2  +4.44V  +4.43V  +4.52V
3  +3.45V  +4.43V  0V
4  0V  -8.44V  -4.13V
5  +4.43V  +4.42V  -8.42V
6  +4.43V  +4.43V  +3.97V
7  +4.41V  +4.26V  +5.29V
8  +8.87V  +15.92V  +8.82V

I don’t know whether these are the “correct” voltages, but mine sounds good so…

Update (21.06.2012): Fixed an error on the layout where gain lugs #1 and #3 were swapped. Thanks to Dieter Brenner for pointing this out!

Updated: 12 April, 2013 — 15:31


Add a Comment
  1. Thanks for the reply, looks you were right 🙂 Got it working now by replacing C3 and the 1M pulldown resistor, which i measured only 170 kohms instead of 1M. Finally boxed: https://s31.postimg.org/6mt3pe4bv/99myths.jpg

    Made a little mod with the clipping stage and the 3.9nF-cap, so different diode types can be switched, and the different caps from 3.3 to 20nF for the bass/mid-tone response. awesome device.

    Thanks again, great site, Harald!

  2. Hi john,
    Sorry to hear it’s not working as it should. Not too much I can do to help either, I’m afraid. Could the pops be due to a poor ground connection or faulty input/output caps?

  3. Great layout, thanks Harald!

    Sounds awesome, just one thing, I have pretty loud pops when engaging, also when I switch off. I have checked the circuit several tims, but I didn’t find any mistakes.

  4. Hi Jonathan,
    I have to admit I’m not totally understanding what is happening here. I’m thinking you’ve built the whole circuit horizontally mirrored, but you have to correct me if I’m wrong. Maybe it’s a case of different perspectives?
    All my layouts are drawn as if the board is lying copper/strip side down, and with components mounted on the non-conducting side facing upwards. The copper strips and trace cuts can be seen on the layout as if the board material was translucent. I.e. when preparing the vero board you should flip it around, copper side up, and add the trace cuts mirrored.
    Am I making any sense or is this a different issue altogether?

  5. I’d like to make a comment based on my main mistake with this build..
    When doing all of the layout and cuts, I had the trace side of the vero board facing me, and copied the whole layout but stuffing the components in from the rear, including the IC sockets! In doing so, the pinouts of the ICs were horizontally reversed.
    So if you’re getting ridiculous voltages and 8.x vdc on pin1, your IC sockets need to be on the reverse side of the board.
    Just an error I hadn’t seen anyone else mention.

  6. Hi Spencer,
    I have to disappoint you I’m afraid. I’m not sure what the problem might be. Have you checked your IC voltage readings against the ones I posted?

  7. Harald,

    Great layout – I built this and it sounds fantastic!

    Except –

    When the output is higher than about 50% and I move the gain to about 75% or higher, there is an underlying static or noise like it’s driven too hard or I’m getting noise from somewhere. Any ideas?

    I’ve changed out the IC’s (all three of them) to no avail and now I’m tracing all the components.

    If you have any direction for me on where to look, I would appreciate it.

    Thanks, man – Great schematic!

  8. Rodney, maybe this will help a little.


  9. Hi Harald
    If I use a 3pdt stomp switch do I ignore the middle row (4,5,6) or the row to the right (7,8,9)?

  10. Rodney, see answer under the request page.

  11. R5/R10, both 27k, should set the bias voltage (approx. half your supply voltage) that’s going to be used a lot of places, including IC1 pin #3. R9 is responsible for raising pin #3 DC voltage to this bias voltage.
    You should read roughly +4.5V DC at strip “b”, left side (where “Gain 3” also connects). If it’s not you might have a related component shorted or something similar; solve that.

  12. Any possible way to get a good diagram/picture from any of the successful builds? I’m having trouble with wiring the board to the hardware,gain pot, board to switch etc. Any help would be greatly appreciated. I have gone thru the board meticulously. It’s exactly as the diagram. Just need help wiring it up. Thanks!

  13. Can somebody point out what are the components that could affect IC1 pin3 voltage? It´s kind of frustrating to randomly swap components in hope to find the suspect. Every component is in the right place, all resistors are measured, cap values checked visually and different IC´s tested.

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