Tuesday, 5 August 2014

EHX Big Muff Pi with Tone Wicker

Thanks to Miro for his great work with the trace for this one.  This is more an adaptation than a verbatim clone, but will give you the same results.  The original used a CD4066 quad bilateral switch to do the Tone Wicker switching which seems very much like an unnecessary inclusion when you consider all it is doing is bypassing the 470p base collector capacitors, so it seemed that instead of using a DPDT switch and CD4066 with the associated increase in required board space, it makes much more sense to simply use a 3PDT toggle for exactly the same results.

Info about the original from Electro Harmonix:
The Big Muff Pi with Tone Wicker taps into the sonic power of the legendary Big Muff Pi, but creates new tonal possibilities at the flick of a switch -- or two. Use the Wicker switch to open up three high-frequency filters for raspy, sustaining distortion with top-end bite, or flick on the Tone switch to bypass the tone control for unabated tonal slam. Want the original Big Muff sound? Just switch off the Wicker and turn on the Tone. The ability to create your own personal Big Muff sound is what truly makes this the Wicked Wicker.








33 comments:

  1. Great!!
    Is the original schematic of this post in the "usual" places?

    ReplyDelete
    Replies
    1. Is the 'tone wicker' 3pdt the second 3pdt including the on/off 3pdt or does the one pictured do double duty?

      Delete
    2. the tone wicker is a 3pdt toggle switch.
      for the on/off you'll need the normal 3pdt foot switch.

      Delete
  2. I used a resistor instead of a jumper between lug 1 and 4 on the tone bypass switch to help even out the massive volume boost that accompanies the tone bypass. A 100-140k should approximate the loss of the tonestack. A small (100-470p) cap from lug 1 to ground will also remove the massive hiss but still leave lots of extra treble.

    ReplyDelete
  3. damn you miro, another big muff?!?!?! i just finally built the 78 Dual Op Amp version, and already built a green russian, and rams head. i swear its going to take me forever to build all of them. but you can never have too many muffs. i guess i'll have to just put the muff at the top of my list today, got to go back to the cave and fire up the soldering iron....

    ReplyDelete
  4. Woot!
    Another to add to the growing list... I like this one A-LOT!
    Thank you mirosol!

    ReplyDelete
  5. Miro - No, I haven't built this particular BMP, they were general comments about muffs with a tonestack bypass that I have built.

    ReplyDelete
    Replies
    1. Ah! Good thing i asked. I was nearly hitting the big red Verified button already :)
      +m

      Delete
  6. You can add this one as verified.

    Thanks for adding this version I defiantly think this one is worth adding another muff to everyones collection. The wicker is cool it is subtle but adds clarity to chording. The tone on/off is a nice touch too. Beware though it is a huge volume jump when you switch it off. I didn't add the resistor between 1 and 4 like mentioned in post above I think having the massive headroom on tap is a plus. With tone off it is a very open sound nice change to my USA muff.

    I will add a video on my days off this week stay tuned :)

    Pic of my build right before I boxed it up. ... and added one more cap I missed doh!
    http://instagram.com/p/rg23l1hTVD/

    ReplyDelete
    Replies
    1. Excellent, thanks for verifying Ryan, I look forward to the vid

      Delete
  7. I was wondering if anyone had the layout for the Wampler Velvet Fuzz? I've got the schematic, but I've never translated it to tagboard before..

    ReplyDelete
    Replies
    1. There is a add-on board layout in the forum contribution section for Plexi-Drive.
      +m

      Delete
  8. Drake: I did an all-in-one veroboard for the Velvet fuzz here -

    http://i80.photobucket.com/albums/j190/Leeroyfunk/velvetfuzz_nocentelli_vero2_zpse76501b1.gif

    ReplyDelete
  9. I appreciate the information, both of you.

    ReplyDelete
  10. I'm not sure why, but my wicker doesn't appear to working. In the video he hits that wicker and he can roll back the sustain and still have distortion. With mine in either setting, if I roll the sustain under 3/4 there is no distortion at all. Maybe I have something else screwed up too. Any thoughts?

    ReplyDelete
    Replies
    1. measure your transistor voltages and let us know them

      Delete
    2. Top Left Top Right
      E - .33 E - .02
      B - .86 B - .58
      C - 7.87 C - 7.41
      Bottom Left Bottom Right
      C - 7.39 C - 7.39
      B - .58 B - .58
      E - .03 E - .03

      Delete
  11. what would I omit from this schematic to have the tone pot omitted and the wicker on permanently?

    ReplyDelete
  12. Firstly, thank you so much for this fantastic site and wealth of information
    I have built 2 previous pedals from this site with fantastic results!

    I am having some issue swith this build.
    I get very faint and muffled sound with alot of background noise.
    The tone and wicker switches cause intermittent behaviour.

    I have checked for any bridges and bad joints and don't see any issues.
    I have tried various BC550 trannies and get the same results.

    Any pointers or ideas would be greatly appreciated.

    Voltages as follows:

    Q1: C: 4.18V B: 0.67V E: 0.056V
    Q2: C: 4.19V B: 0.67V E: 0.056V
    Q3: C: 4.17V B: 0.67V E: 0.056V
    Q4: C: 6.50V B: 1.08V E: 0.51V

    ReplyDelete
  13. Hi,
    can i replace the 27pf by 22pf and the 430 by a 500 pf ?

    Franck

    ReplyDelete
    Replies
    1. i don't see why not. it may change the effect of the tonewicker, but you may end up liking that more then what it was stock. what you can do is socket those caps and try the 22pF and 500pf and see how you like it. if you don't change them.

      Delete
    2. Ok Thanks for the fast answer !
      i never remember put a socket for try an electronic component ! thanks for the idea…
      i let you know !
      Franck

      Delete
    3. awesome. since those caps are part of the tonewicker switch, and i've build many other muffs, just haven't gotten around to this one, i'm not sure what it will change. if it causes an issue, just get the caps you need, im sure if you just needed the two caps i'm sure someone would have 2 to spare and send them to you. can't wait to hear how it turns out.

      Delete
  14. hi
    just to be sure…
    the studs 3/6/9 of the tone wicker are free of wire ?

    ReplyDelete
    Replies
    1. correct. i don't see it listed that any wires connect to those lugs, so they should be empty.

      Delete
  15. Hello everybody !
    is somebody have a pcb layout of this marvelous pedal ?

    Franck

    ReplyDelete
  16. This comment has been removed by the author.

    ReplyDelete