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Tuesday, 25 February 2014

EHX Germanium4 Big Muff Pi

Ok. This has absolutely nothing in common with all the other 14 different versions of Big Muff Pi. As the effect has two individual sides, one for distortion and other for overdrive, i thought i'd draw the sides as a separate layouts. You can, of course, use one 16 x 31 board to have both effects on a single board.  Or tweak one of them to your liking and fit it in 1590B. With eight pots and two stomp switches, i don't see even Javi fitting all of this in 1590B :)





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17 comments:

  1. IvIark25 February 2014 at 13:29

    > With eight pots and two stomp switches, i don't see even Javi fitting all of this in 1590B :)
    Ha ha, oh you had to challenge him didn't you! :o)

    This is a bit of cheating from EHX to add NKT275 mojo and then end up using them as clipping diodes in the distortion side.

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    1. mirosol25 February 2014 at 15:26

      I sure would like to see him succeed! :P

      Design is pretty non-standard, which is nice. I'd still say it's a waste of NKT275s though...
      +m

      Delete
    2. JaviCAP25 February 2014 at 20:32

      Sadly, I have to admit that this one is imposible in a 1590B.... maybe in a 125 :) If I build this one will be in a Retex RM6, it wuld fit perfectly, but I find two problems for building this effect:

      - I think too that this is a waste of germaniums
      - You can get this effect used in great shape for about 50-60 euros.

      J.

      Delete
    3. mirosol25 February 2014 at 21:25

      You could use some cheaper germs than NKT275s. I think it could even sound better with silicon transistors..

      Used ones seem to go for 60-70€ here, but still pretty cheap. Main reason for drawing this was that either of the circuits could be tweaked and used separately.

      But of course i needed to tease you Javi! You have done quite a few impossible squeezing ins in the past :)
      +m

      Delete
  2. Unknown25 February 2014 at 14:18

    I had the original and it was a fairly decent pedal, quite fun to tweak. Might revisit via DIY. Thanks!

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  3. Zach28 February 2014 at 04:51

    Silly questions, but are the nkt's are being used for clipping in both circuits? Cause I was thinking if they are, then wouldn't this be a great use for those low gain, leaky Ge's we may have laying around? From all the Russian Ge's I've started hording there are a few in the 20-30HFE range, and have been looking form good uses for them. I was also thinking this would be a good canvas to tweak for more low end retention, maybe even add a blend control to for a great bass fuzz/od/distortion..

    Also, as a side not, I've been on the lookout for one of these used for awhile, and either people want close to the new price for them, or they're all new.

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    1. drdFX28 February 2014 at 06:54

      Only on the distortion side, there you can even use Ge diodes if you want.

      Delete
  4. mirosol1 March 2014 at 19:08

    There's obvious error on the dist side layout. I'll be updating it soon...
    +m

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    1. mirosol1 March 2014 at 20:14

      Now fixed...
      +m

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    2. Zach2 March 2014 at 05:05

      awesome miro. i haven't had any time to build anything for awhile, so i can't check to verify either layout. hopefully someone else can soon, would love to play with these when i can build again. also, any idea of approx. HFE for the nkt's for the od side?

      Delete
  5. Claudio23 August 2017 at 16:41

    if I wat to eliminate te Volt pot and leave at max volt, I just eliminate the 6.2k resistor and remove pot putting bridge from volt 2 to volt 1?

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    1. mirosol23 August 2017 at 20:08

      Leave 6k2 out and link volt 2 to volt 3.
      +m

      Delete
    2. Claudio31 August 2017 at 20:18

      thanks, will be my next project to use some germs (even though is for clipping)

      Delete
  6. Claudio15 September 2017 at 16:03

    Since ntk275 are for clipping, hfe is important? I have some 30-50 hfe PNP Germ around there

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    1. mirosol15 September 2017 at 22:06

      Nope. Those otherwise useless devices will work fine here.
      +m

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    2. Claudio7 August 2018 at 21:09

      I guess the stripboard is not right, actually I built and didnt work, I found this schematic and found some differences, can you check it out http://guitar-fx-layouts.42897.x6.nabble.com/file/n4366/ge4bigmuffdistorsion.png

      Delete
  7. Claudio20 September 2017 at 13:21

    i guess this is not verify following this schem seems to be lots of differences on tl072 connection http://freestompboxes.org/viewtopic.php?f=1&t=20612

    ReplyDelete