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.

Monday, December 8, 2014

Electro Harmonix Ram's Head Big Muff

There are a lot of versions and subversions of the Big Muff. Many consider the Violet Ram's Head to be the best, though many consider the Triangle, or IC, or Green Russian, etc. the best. YMMV

This one has the pots hard mounted to the board, though depending on the enclosure you use, it may be best to wire them off-board. This layout is heavily inspired by the original Ram's Head circuit board, just resized for more typical sized components. I've also added a polarity protection diode, power filtering cap, and an LED resistor.


EHX also used this same circuit for the Guild Foxey Lady (3-knob) as well as several other OEM pedals EHX produced. 

31 comments:

  1. very good muff, its pink floyd in a box, but im going crazy here as im making a 3 in one with this, the green russian and the triangle...im just wondering if i will put a buffer in there or an SHO ....i might finnally get to use those super large boxes a friend gave me !

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    1. Buffer would probably serve better than a SHO. Plenty of gain on tap in a BMP, let alone 3 in one box! Sounds like a cool project.

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  2. Pedal enclosure is wild cherry wood. It looks like this:

    http://www.upslike.net/imgdb/Untitled-1-e807a5.jpg
    all done by my hands!

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  3. Wow i have to give you an big thanks to all your work here. THANKS THANKS.
    I have to ask if you can make an version of http://www.bigmuffpage.com/images/KR_1973_V2_No%203%20Schematic.jpg that one?
    Sorry when i ask that. and its only a point of changing resistors or so.
    Iam total new to this kind of thing
    Greetings and all the best to you

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  4. Hi, thanks a lot for you contribution. Any chance you could provide the .gbr file for this?

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    1. I don't do gerbers as DIYLC has no way of exporting them. You could redraw it in Eagle if you want gerbers, or have someone else etch you a board if you're not able to do one yourself.

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  5. Isn't a linear pot better in sustain control?

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    1. That's really just a matter of personal taste. EHX used whatever they had on hand pretty much, so both tapers have been used. Use what you got/what works best for you.

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  6. Hi, thank You!
    I've finished it last night, it works fine. Just a little tip: the Tone Pot would have to be reversed, in the way it is mounted in the layout, at the minimum position the sound is full of treble, at the maximum full of bass. I think that the correct way is to have bass at min and trebble at max.
    Thank You so much!
    Regards!

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    Replies
    1. This layout is based on the original Ram's Head circuit board, which I think (it's be a while since I did this one) had the tone control reversed.

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  7. Built this, straight forwards and good looks layout that lead me step inside this circuit during assembly, really enjoy the experience, thanks for the neat layout~ share my board: http://i1244.photobucket.com/albums/gg569/pakkee66/DIY%20PEDAL/RamsHead%20cb2_zpsvwoiya82.jpg

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  8. Which enclosure would this fit best in for an inexperienced builder?

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  9. thanks for the quick reply and great website

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  10. I just built it. Everything works great except the sustain pot. Its basically another volume pot. It sounds great when its all the way up but the volume/gain decrease when I turn it down. Its almost silent when sustain is at noon.

    Any suggestions?

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    1. Its my first build without using a kit. I googled it, noticed others have had similar issues with bmp builds, but I couldn't find a solution.

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    2. The Sustain pot is the gain control of this circuit. I'm guessing you used a B100k (linear taper) pot there. Try using an A100k pot (log taper). Should give you a better sweep.

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    3. I just realized this an hour ago. Everything works just fine and this thing sounds great!thank you!

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  11. Hi, i make this pedal and it doesn't work but dc voltage arrive only at tone pot, is it normal ? Can Someone help me my email is frarob1990@gmail.com , please Who already did this pedal help me thanks

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  12. Works like a charm and sounding great. Does require a silent power supply however. Using a battery at the moment. I used 5088, boxed type film caps, and metal film resistors. Could the sound be improved using more vintage tropical fish caps, carbon resistors etc?

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    Replies
    1. Using mojo components could change the tone a little, but whether or not it changes for the better is in the ear of the beholder. In my experience/opinion mojo parts act more as a placebo than anything else.

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    2. In that case i'll leave the pcb as built. Only have to c-type reverse-log the sustain and volume for the more logical right=louder operation. Thanks a lot for this great layout!

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  13. I've built it and it works, but it sounds more like an overdrive, not as dirty as the original. I looks like it lacks some gain. I've replaced 3.9nF with 4.6nF (couldn't find 3.9nF anywhere). Do you think this can be the reason?

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    1. That wouldn't do it. What transistors and diodes did you use?

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    2. Instead of 1N4001 I mounted 1N4007
      Q1-4: BC550B
      D1-4: 1N914F
      Thank you for your help!

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    3. The transistors may be the culprit. The BC550B typical HFE is around 250 I think. You generally want something higher, like 500 (which is typical in the BC550C).

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    4. Today I replaced transistors to BC550C eventually. Now it sounds lovely! Big, big thanks!

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