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.








Posted by at 17:29
Tags: , , ,

40 comments:

  1. zedsnotdead5 August 2014 at 18:47

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

    ReplyDelete
    Replies
    1. mirosol5 August 2014 at 18:49

      Try FSB.
      +m

      Delete
    2. Unknown6 August 2014 at 13:41

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

      Delete
    3. ξεναγός νεκρόπολης6 August 2014 at 13:57

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

      Delete
  2. nocentelli6 August 2014 at 16:15

    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.

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  3. Zach6 August 2014 at 20:02

    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. Jimijam6 August 2014 at 23:32

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

    ReplyDelete
  5. nocentelli7 August 2014 at 08:51

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

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    Replies
    1. mirosol7 August 2014 at 17:08

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

      Delete
  6. Unknown10 August 2014 at 11:05

    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. IvIark10 August 2014 at 11:56

      Excellent, thanks for verifying Ryan, I look forward to the vid

      Delete
  7. Drake Bowman12 August 2014 at 08:22

    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. mirosol12 August 2014 at 09:48

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

      Delete
  8. nocentelli12 August 2014 at 19:10

    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
    Replies
    1. Piergiorgio30 May 2015 at 15:54

      Sorry, is the IC 386 the LM386N?
      Thank you

      Delete
  9. Drake Bowman17 August 2014 at 04:26

    I appreciate the information, both of you.

    ReplyDelete
  10. kirshman10 September 2014 at 22:51

    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. IvIark11 September 2014 at 08:04

      measure your transistor voltages and let us know them

      Delete
    2. kirshman11 September 2014 at 17:47

      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
    3. kirshman11 September 2014 at 17:59

      that was with wicker on

      Delete
    4. kirshman15 September 2014 at 16:52

      same numbers with it off

      Delete
  11. Johnathan27 February 2015 at 00:20

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

    ReplyDelete
  12. Unknown22 May 2015 at 15:13

    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. Unknown20 June 2015 at 13:43

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

    Franck

    ReplyDelete
    Replies
    1. Zach21 June 2015 at 02:04

      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. Unknown21 June 2015 at 12:15

      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. Zach21 June 2015 at 21:31

      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. Unknown24 June 2015 at 21:08

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

    ReplyDelete
    Replies
    1. Zach24 June 2015 at 21:56

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

      Delete
  15. Unknown29 February 2016 at 20:28

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

    Franck

    ReplyDelete
  16. Unknown19 June 2016 at 22:06

    This comment has been removed by the author.

    ReplyDelete
  17. ΑΘΑΝΑΣΙΟΣ ΚΑΣΒΙΚΗΣ18 September 2016 at 16:51

    This comment has been removed by the author.

    ReplyDelete
  18. Unknown30 January 2017 at 06:54

    Hello, is this the only schematic around by mirosol?

    http://mirosol.kapsi.fi/wp-content/uploads/2014/07/EHX-BMPwTW.jpg

    I just completed the build in my own custom PCB and it's working just fine, the problem is there is a lot of noise with the tone wicker in the (ON?) position (switch connects no wires) i realise it has to do with the first stage (tested it touching with my fingers and i guess maybe the wires are a bit long? (5cm) is there any remedy to this? i've read all about metal film resistors, BC550C vs 2N5089 and these won't solve the problem... this all is really affected on high sustain settings, any ideas how to make the noise a bit less?

    thank you!

    ReplyDelete
    Replies
    1. Unknown7 August 2017 at 01:26

      I have the same problem with my wicker switch. Every-time I touch it the noise gets worse then it goes away.

      Delete
    2. Unknown1 October 2017 at 12:21

      Grounding issue cuzzin'

      Delete
    3. Unknown1 August 2018 at 15:14

      Can you say something more about this issues? I have the same problem and i cant find any solution to fix this

      Delete
  19. Chance31 July 2017 at 12:05

    Built this with matched Q1 & Q2, also matched Q3 & Q4 BC550C's, can't remember the HFE values. Sounds awesome, similar to the demo. Thank you for the layout!

    ReplyDelete
  20. Unknown1 October 2017 at 12:20

    Built

    ReplyDelete
  21. Schmoll8 July 2020 at 00:22

    I built this pedal a while ago, I absolutely love it, I love it, I love it, I'd sleep with it <3

    More seriously, I used a 3pdt toggle switch on the tone bypass to be able to put on a LED. Originally I planned on putting it to the tone wicker but, it seems that I can't, but it's fine.
    The tone wicker seems kinda useless, I mean, you can notice it if you pay real attention but it's not that obvious.

    Anyway many thanks, very cool stuff !!

    ReplyDelete

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