Thursday, 15 March 2012

Klon Centaur - Bare Bones - True Bypass

[Updated 4th July 2014 - correction to treble control resistors] 

And an even simpler version using true bypass switching, and so omitting the buffer components.  Verified.


43 comments:

  1. I am having a ton of trouble with this layout. Built it twice, first time with an older version, and this time with this one. Both times the same thing happened, no signal passed at all. I am getting voltage at all the correct pins in my IC's, and a little bit at the diodes (more at the 1n4742), but no signal is being passed. Let me know if you have any ideas about what could be wrong, I have checked my wiring and tried a few footswitch schemes and nothing worked, so I am assuming that something is awry on the board.

    ReplyDelete
    Replies
    1. Hi Will, I'll go over it later today and see if I can spot anything. Thanks for the feedback.

      Delete
    2. I've just been over it and can't see anything, it appears to match the schematic with the exception of the buffer components which I removed. Can you take a front and back pic and post the links so I can have a look?

      Delete
  2. Here is the top: http://i138.photobucket.com/albums/q258/willbjorndahl/IMG_0935.jpg

    And the bottom: http://i138.photobucket.com/albums/q258/willbjorndahl/IMG_0936.jpg
    I had to create an extra row at the bottom, but I think I did it correctly.
    Thanks a lot for your help Mark!

    ReplyDelete
  3. Hey Mark.
    Found a few solder bridges on my build, fixed them and now it works just fine.
    Consider this verified.

    ReplyDelete
    Replies
    1. Excellent, I had this setup to build because I couldn't see anything obvious with yours so thought I should try it myself to see how it ended up. Glad you got it going.
      Have you used an original Klon, or a complete clone? If so I wondered how you thought they compared to the 9V true bypass version? Thanks for verifying!

      Delete
  4. I have never tried any version of a real Klon, decided to build this one to try it out.
    So far it feels a little bit weird (spongy feeling compared to my usual Tube Screamer) but I can dig it.
    Im sure its comprable (at the least) to the real deal Klon.

    ReplyDelete
  5. So I built one using your layout and I'm having a few issues and I was wondering if you had any pointers. First of all, the build works, but I find that the output is greatly diminished compared to my other Klon builds that include a charge pump. This build seems to be unusable as a clean boost and while it does have a bit of boost, the gain knob must be nearly dimed.
    As well, if the gain pot is at zero (or close to it) the pedal cuts out and pops slightly, regardless of the levels of the treble/volume knobs. It seems that the lower portion of the gain knob is not getting along with the circuit. Any advice as to what could be causing this?
    Thanks!

    ReplyDelete
    Replies
    1. I haven't built this yet so don't know from my own experiences, but I did read in the original thread on FSB that the output was lower than the complete Klon(e). Yours does seem to be more extreme than they described though, maybe Will can offer some info about how his compares to your description?

      Delete
  6. How does this compare to the circuit used in the real Klon Centaur?

    ReplyDelete
  7. How does this compare to the circuit used in the real Klon Centaur?

    ReplyDelete
    Replies
    1. I deleted my original reply, I thought this was the full Klon thread. This version is designed for true bypass switching and so removes the buffer components and it also omits the charge pump and instead both ICs run at 9V. If you're a member of FSB, read earthtonesaudio's post here:

      http://freestompboxes.org/viewtopic.php?f=13&t=7526

      That explains his theory behind it and why he suggests the end results will be comparable.

      Delete
  8. Anyone know a cheap (to the UK) source for the TLC2262? - or is there an equivalent which wont sound noticeably different?

    Thanks,

    Ian

    ReplyDelete
    Replies
    1. I've got mine through ebay - those chips aren't particularly cheap though. May be worth noting that i didn't notice anything different soundwise when comparing TLC2262 and TL072. I was to build any klon again, i would probably go with NE5532 or AD712.
      +m

      Delete
  9. Hi Mark...is there a kit available for this version too??

    ReplyDelete
  10. Can this be ran at 18V also, or is this strictly 9V. I already tried slowly raising the voltage to 15V but didn't dare to go further as the current consumption seemed to go up as well.

    ReplyDelete
  11. Just finished this build and got it working after I re-reamed one of the cuts Am getting decent output with the volume dimed and am satisfied with the sound. For the diodes, I used 2 NTE 109s which are supposed to be equivalent to OA92s. The only issue I am having is that I cannot get the LED to light up. Hooked up the + side to the LED+ wire and negative end to the switch. I am assuming that the on board 3.9K resistor eliminates the need for any other resistors for the LED. Any ideas why the LED is not working? Swapped it out with another one with no luck.

    ReplyDelete
    Replies
    1. Found the problem. Forgot to connect the ground wire on the 3PDT switch. Unit is working great now and I am getting plenty of output from it. Originally built this for a friend but am going to have to build another one to add to my pedal board.

      Delete
  12. This circuit could also really use an additional filter cap for the supply voltage. I put a 220uf in, and it helped the hum from a wall-wart significantly.
    Also, the 100k resistor on the bottom right of the board can be increases a little to get a bit more output, right?

    ReplyDelete
  13. Hi,

    can I use 1n270 instead of 1n277 ?
    or even 1n34a?...
    thanks

    ReplyDelete
  14. Hey just trying to recall for the life of me what width vero will fit in a 1590B? Is it 21 columns/rows with the edges filed?

    ReplyDelete
    Replies
    1. 22 will fit in with the edges filed down

      Delete
  15. D3 1n4742 = 12v Zener diode? Can I run this pedal @18v with such a diode in D3?

    ReplyDelete
    Replies
    1. The zener will drop the voltage so yes if you want to run it at 18V don't bother with it. Make sure the ICs you're using can handle it though, I have shown a TLC2262 here which has a maximum voltage of 16V which is why I kept the zener in the layout.

      Delete
    2. Thank you for the hint ;-)

      Delete
  16. Okay I hate to sound like I have no clue what I'm doing, but I don't think I do. So the Input goes to the middle pin on the switch? Where is the output? off of the volume pot?

    ReplyDelete
    Replies
    1. The layout drawing shows the input between the 9v and the LED leads. The last note on the drawing reads "Volume 2 to output". The rest of what you need is here-> http://tagboardeffects.blogspot.com/2012/02/offboard-wiring.html

      Delete
  17. I'm going crazy with this build....
    I am a novice, I just copy what i see and am learning every build. Most of the builds work perfectly.
    With the klon I started with the simplified trua bypass, didn't work.

    Then the one with the one with the icl7660S true bypass, nothing again.

    For the 390N I used two paralel caps. for the 422k resistor I just user a 430K.
    For the zener I used a 12V 1,3 W Could that be the problem????
    The parts list says a 12V 500mW.... A 1n4742 is not available where I live.
    I

    ReplyDelete
    Replies
    1. The zener doesn't matter, in fact you could snip it out and it wouldn't change anything. Post all the IC voltages to see if that gives us any clues

      Delete
  18. any sutable subs for the tlc2262 ? ... can't find them locally and kind of in a hurry so ordering them isn't an option (for now) ... mirosol said he "didn't notice anything different soundwise when comparing TLC2262 and TL072" ... but is this with both ic's beeing the same? I can find the normal bunch around here - 072, 082, 4558, 4559, 4580.

    ReplyDelete
  19. Can anyone help me with this build? Signal is good fot a couple of seconds when power connected but then futzes down to a rasp and then quiet clean signal. The gain pot then seems to die off about half way towards maximum gain. Can't find any shorts or bridges in the circuit. Shorting out one of the 47uF electrolytics momentarily restores gain but I'm note entirely sure where to go with that.

    ReplyDelete
    Replies
    1. Update on this, I'm using a TLC2262CP for IC2, is there another 2262 variant I should be using instead (2262AIP?) voltages are all over the place:

      IC2
      Pin 1: 0-47.5mV (so far, gradually rising),
      Pin 2: 2.81V
      Pin 3: oscillating really fast
      Pin 4: 0v
      Pin 5: 0-175mV (and rising...)
      Pin 6: 0-1.87V (and rising...)
      Pin 7: 0-3.5V (and rising...)
      Pin 8: 9.48V

      Also, IC2 seems really wide open to interference - hovering a finger anywhere near it produces a loud hum.

      Here are my IC1 readings, if useful...
      1: 4.12V
      2: 4.12V
      3: 3.32V
      4: 0V
      5: 3.14V
      6: 3.82V
      7: 1.31V
      8: 9.48V

      Delete
    2. Forgot to say, thanks for a great blog!

      Delete
    3. IC1 looks ok apart from maybe pin 7 being a little low, but IC2 is wrong on so many levels. Pins 3 and 5 are connected to vref via a link and so should be at half the supply voltage, which is provided by the 2 x 27K resistors that connect from vref to supply and ground, making a voltage divider. You're getting different readings at pins 3 and 5, and that just can't happen if the links are connected as shown. Have you put the double link where it is shown next to D3? What voltage are you getting between Gain 1 lug 2 and ground?

      Delete
    4. This comment has been removed by the author.

      Delete
  20. Thanks for the reply. IC2 escaped down the gap between the floorboards yesterday so rather than pull the floor up i'm going to order another one in. Any 2262 variant I should be aiming towards?

    Double-checked that double link and the upper part of it had no continuity with the lower part, resoldered the connection adjacent to teh 47u cap and now seem to be getting consistent voltages across the IC2 socket.

    Voltage between gain lug 2 and ground (both channels) is 4.72v

    Thanks for the tip off, really helpd a newbie narrow things down.

    ReplyDelete
  21. I'm a little unsure on two things:
    1. For D1 and D2, I can' really tell from the way it's phrased. Do you mean to say D1 and D2 both be either a OA91 or a 1N277? Or is D1 a OA91 and D2 a 1N277?

    2. For Gain 1 and Gain 2 (representing the dual gang pot), which row is Gain 1? Gain 2?

    ReplyDelete
  22. Hi _

    In most schematics and layouts they use a matching pair. So D1 and D2 are both OA91 or 1N277. No one is 100% sure what diodes are in the original but Mark is suggesting these two varieties come very close. You can stick in whatever combo you want though. Some people swear BAT41s are even better or 1N34A or a mix of any.

    I'm no dual gang aficionado but if a dual gang pot is really just two normal pots together I doubt it makes any difference which row you use for which as long as you get lugs 3-2-1 correct on each pot. Dual gangs are often used for L and R stereo functions so each pot needs to work identical even though it's one giant pot. Happy to be corrected cos all of this statement is a guesstimate.

    :)




    ReplyDelete
  23. I built this one today and it fired up first try but it's very dark sounding and there doesn't seem to be much of a tonal sweep when turning the treble control. Fully CC is slightly more bassy, fully CW is slightly brighter, but the difference is barely audible, and the full sweep is much muddier than the bypassed signal. Gain sweep seems normal. Not much volume on tap... I understand that this one is not as loud as the charge pump version but even dimed there's only a slight boost from unity volume. Any ideas?

    ReplyDelete
  24. Hey Jon Webster or anyone, figured out the low volume output or gain pot cutting out a little past half way?

    ReplyDelete
    Replies
    1. I was able to fix the gain rotation cutting out completely by snipping the 3k9 CLR resistor. I opted to connect the LED the traditional way (off board wiring FAQ), rather than connect the + LED leg to the board itself.

      After I removed that, it worked great, and sounds great too! Just like my Aion Electronics Klon KTR clone! (minus some available output volume)

      Delete