This is a library of perfboard and single-sided PCB effect layouts for guitar and bass. I'm not an electrical engineer by any stretch of the imagination, just a DIY'er who likes drawing layouts. It is meant for the hobbyist (so commercial use of any of these layout is not allowed without permission) and as a way to give back to the online DIY community.

Thursday, January 8, 2015

EHX Big Muff - Green Russian

With the exception of the IC BMP ('77, '78) you can theoretically build just about any version of the Big Muff on any other version's layouts, but the values listed in this one are for the Tall Font Green Russian version. This one is smaller than the BMP layout I did with on board pots and you should be able to fit it in a 1590B if you shave down the sides of the board a little.

One of the better sounding versions of the Big Muff (IMHO anyway) and sounds great on both guitar and bass.



And if you want to cut through the mix a little better, here's the Green Russian with a modified tone stack, adding a mids control. Pinkjimiphoton over on FSB suggests using a higher value pot for the mids control (250k-1M) than the normal 100k that's listed. 


Update 3/16/15:
Modeffected pointed out that these 2 layouts were missing the 12k resistor from the power rail to the collector of Q3. Both layouts have been updated and should be correct now.

25 comments:

  1. what's the dimension of pcb? i want to make one pair of pcb of your's page but i don't know the size, sorry for my english . thank's :)

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    1. It's 2.3 x 1.3 inches or 58.5 x 33 mm. Good luck with the build and let me know if it works for you.

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  2. on the stock green pcb layout is a missing resistor that should go from the power rail to the collector of the third tranny from the left.
    i put it under the board as i was troubleshooting and it work as it should.

    when i look at the layout with the mids add-on, the same resistor is missing.

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  3. Thanks for catching that. Updated the layouts.

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  4. Verified (mids control version). Very Nice tone!!

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  5. i have to say this is the best version of big muff out there. also, verified.

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  6. Dumb question, where is the "out" pin in these two boards?

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    1. It's in the notes on the bottom left. Output comes off the 2nd lug of the Volume pot.

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    2. Thx! I don't know how i missed that, as i said, dumb question :)

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  7. I'm into this one!
    The "mids" knob add in parallel the 47nf cap to the 3.9nf one, am I right?
    So, I can play with that value

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    1. They're not really in parallel, as the Mids pot is really before the 47n cap, but yes, that 47n value can be tweaked for the mids.

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  8. Built this, and it passed signal right away. All the pots work, except it barely distorts. When I pull the first transistor, nothing happens with the sound, could this mean I have short? Possibly the 500p is bad?

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    1. Yeah, something is definitely shorting. Time to pull out the multimeter.

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  9. Can 470pF capacitors be used instead of 500pF?

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    1. I'm trying to debug my build.

      Voltage readings are:
      Q1: C=7,49V; B=0,62V; E=0,047V
      Q2: 7,42V; 0,62V; 0,049V
      Q3: 7,30V; 0,58V; 0,011V
      Q4: 7,68V; 0,96V; 0,386V

      I assume Collector voltages should be around 3-4V.
      Any ideas what might be wrong?

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  10. I've checked everything multiple times. There's just clean sound of the bass guitar and high pitch noise. No fuzz at all. I used C549B transistors. Please help. :)

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    1. If you're using the BC549B you probably need to use higher gain transistors (like the BC549C). I'm guessing the clipping stages aren't being amplified enough to create distortion.

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    2. Turns out I soldered the transistors backwards... :|
      Now there's fuzz and all but also some of that high pitch noise...

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    3. Been there. Glad you got that sorted. Try throwing a 10-100n cap from voltage to ground and see if that helps with the noise.

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    4. I've cleaned traces a little bit and the noise is gone.O_O Thank you for your help. Great project.

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  11. Just put one together w/ mids control and sockets for the transistors inside the carcass of a destroyed Little Big Muff Pi. Initially using MPSA18. Sounds huge. Thanks!

    http://imgur.com/vC9KFpj

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  12. I think the third emitting resistor is 300 Ohm, not 100 Ohm, as it shown in the layout. Am I right?

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    1. You're right, it should be 390Ω. I probably just copy and pasted that resistor and forgot to change the value.

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    2. I guess it isn't too critical: maybe a bit more of imperceptible gain?

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