Big Muff Pi (Triangle Version)

by gaussmarkov

Big Muff Pi (Triangle Version)

This is an NPN Triangle Big Muff Pi circuit that I started working on because Dragonfly was looking for verification help with his own layout. I was trying to make something that would fit in a 1590B. It may not be possible, with the three pots and all. 😉 I took the schematic from

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42 Responses to “Big Muff Pi (Triangle Version)”

  1. scott said:


    Posted 21.08.2007 at 4:25 pm

  2. gaussmarkov said:

    i suggest that you make your first build a kit from the chances for success are highest and that’s important for building interest and confidence. my recommendation is the replica of the electroharmonix LPB2. this is a classic and relatively simple circuit.

    good luck! gm

    Posted 22.08.2007 at 11:17 am

  3. dfx said:

    do you have a pnp version of this fx? i got a couple of ac188 pnp germanium and would like to tinker with them.


    Posted 16.09.2007 at 8:31 pm

  4. gaussmarkov said:

    hi dfx,

    no, i don’t have a pnp version. but you can convert the npn version by reversing the polarity of the battery. if you had any polarized electrolytic capacitors, you would need to reverse their polarity as well. but there’s nothing in this circuit that requires an electrolytic.

    all the best, gm

    Posted 17.09.2007 at 5:05 pm

  5. canbaz said:

    Really nice work. I searched and studied on it really much and find that your schematic is the best, and most reliable.

    I wonder, what are the differences between SYLOD988(The originals), 1N4148, 1N914 diodes. And you dont use a ceramic capacitor for C8. A reason? Is there any diffrence between
    ceramic and film caps?
    There is a PCB pattern here which i noticed some differences and the schematic at this site isnt true can you draw me the schematic of this pattern?

    And i want a sound sample just to hear it before build, please.

    Thanks really much. Well done.

    Posted 23.11.2007 at 3:40 pm

  6. canbaz said:

    Also its better to use linear pots for tone control.100KB pot for tone, 100KA pots for volume and sustain. Dont miss it.

    Posted 23.11.2007 at 3:48 pm

  7. canbaz said:

    Come on… I think the pattern isnt correct too. Can you please just look to the picture that shows inside the pedal which it writes “more detail”. And then tell me which schem is reliable.

    Posted 23.11.2007 at 3:56 pm

  8. canbaz said:

    Ok. After studying on it i undestood that your schematic is perrfect :). But still need answers about caps and diodes, asked above.

    Posted 23.11.2007 at 5:40 pm

  9. gaussmarkov said:

    Hi canbaz,

    I have not been online. I just found all of your messages. I am glad that you figured things out. 🙂

    The 1N914 and 1N4148 diodes are virtually identical. Have a look at their datasheets and you will see this. The Fairchild datasheet for these two diodes is even the same datasheet.

    I do not know how the 1N914/1N4148 compare with the diode that you mention.

    Regarding C8, a ceramic capacitor would also be a good choice. I think capacitor selection depends a lot on personal taste and perception. So I do not give strong advice about the type to use.

    All the best, gaussmarkov

    Posted 23.11.2007 at 6:10 pm

  10. Joe said:

    I’m looking for a bigmuff schematic 3003 It’s an old pedal and i’m very new at this thanks

    Posted 06.12.2007 at 12:02 am

  11. gaussmarkov said:

    Hi Joe,

    I do not know about schematic 3003. I think has a file with several versions of the BMP schematic in it. That is a good starting place. And I bet there is someone out there who has a site with detailed comparisons of the various versions. I just don’t happen to know of one off-hand.

    And this is a good question for Aron’s forum. You may not have joined that yet, so I recommend you check it out:

    Good luck, gm

    Posted 06.12.2007 at 7:35 am

  12. Chris said:

    Hi there,
    I was thinking of using this layout and substituting in the “Swollen Pickle” values as I heard that was essentially what Way Huge did. After comparing schematics between this and the Pickle, I noticed that the Pickle has a battery protection diode and what appears to be a filtering cap on the 9v. Are these items necessary for this build?
    What are your thoughts?

    Posted 06.12.2007 at 12:36 pm

  13. gaussmarkov said:

    Hey Chris,

    My feeling, and I picked this up from MartyMart on the forum at, is that every build should have these features. So if they aren’t in the original design then I add them on a separate, small board or directly on the DC power supply jack.


    Posted 06.12.2007 at 2:33 pm

  14. Chris said:

    Wow, I had never thought about using the DC jack. Great idea!

    Posted 06.12.2007 at 2:42 pm

  15. gaussmarkov: diy fx » Nordic’s Big Muff Pi Triangle Revision said:

    […] sent us a revision of the Big Muff Pi Triangle layout. He added his own artistic touches and created something that differs from most of our layouts in […]

    Posted 31.05.2008 at 2:06 pm

  16. Thaxt said:


    I’m the (very happy) owner of a 1970-71, triangle-era BMP. The trannies are the SPT 87-103 originals, as are the GY819 diodes. All caps are ceramics. (class III?)

    I spent a good deal of time recently (re) scoping out all the componentage, & have built a 2N5088- based close approximation of its (yep-remarkable) sound.

    While some resistor specs are off a bit, & there are components that make it bassier, (mods commonly found on GGG site, etc & others),I think that it’s notable sound derives mainly (tho not enitrely) from those SPT trannies & GY diodes. No one seems to be able to locate the SPTs, & EH is not talking, so I can;t tell their saturation characteristics…there is a whomping 8+ volts on Q3, (the better to really drive that tonestack, I guess). Q1 reads out around 4.3 V, Q2 about 4 V, & Q4 reads around 6.8 V + @ the output.

    The tonestack features a low-cap of .012uf, & the common .004 for a hi-cap.

    The characteristic sonic mojo here is a tough educated guess…I’ve A/Bed it w my mods, & I can see why this thing is so prized.

    Would I put actual mods oton the original board ?

    Lol – I had to hem & haw about just putting in the true bypass switch (silly,but…) & a 9V adapter plug on the soft aluminum side!

    Posted 17.06.2008 at 2:36 pm

  17. Thaxt said:

    Does anyone know if those GY819 diodes might be Shottkys? Or just some silicon variation? EH was likely picking from lg, EZ ily found, grab bag lots of parts, I’d say. Whoever was making these & the trannies, they’re long gone. 🙁

    The IN914s come pretty close to replicating the exact characteristic, Triangle BMP sound envelope ,but, there is a great compressive impact (?) that I think does not come entirely from the 500pf (ceramic) feedback loop caps.

    Posted 17.06.2008 at 2:44 pm

  18. Thaxt said:

    The secret of this pedal is getting that (wide-parameter) tone control into just the right sweet spot for whatever you’re doing.

    While chords & double stops are mindblowing w this (original) thing – smoothly ascending double stops can sound almost like flanger regeneration a bit – any good tweaking & modding can get you into that zone effectively.

    I can’t wait to get a hold of a 14 pin, 3904 transistor array chip, so I can Pickle-ize the Triangle (interpret unexpected metaphor any way u like)

    Posted 17.06.2008 at 2:52 pm

  19. gaussmarkov said:


    Thanks for all the sharing.

    8V on Q3’s collector is presumably producing quite a bit of asymmetrical clipping at that stage. Did you bias your 2N5088 approximation the same? What resistor values did you use?

    Cheers, gaussmarkov

    Posted 17.06.2008 at 8:16 pm

  20. Thaxt said:

    Yes – tho, the voltages on my mod are puny compared to BMP originalis.

    Q3 has a 33K resistor on its collector, 120K on the base to gnd, & 150 ohms from emitter to gnd.

    I did find the (or a) secret to getting IN914 diodes close to the original GY819 ones: just double them in both feedback loops, for a grand total of 8 1N914s – this will give much more impact, sustain, & overtones reminiscent of the 1970 BMP.

    If you triple them (3 on ea side of the to feedback loop on Q2 & Q3, you’ll get one heck of a sustaining superbuzz – albeit with noise + buzz when & if you turn the sustain control up.

    The large 220 + uf cap from V+ to gnd mod didn’t help w this, but, the 3X IN914 diode-in-ea-direction tweak is an awesome mod for some players (or bands’) purposes, & I suggest people just try it out. Maybe some NR in your recordings can tame that extra buzz (not too bad) out.

    The again, some bands would dig that liveness, & hypersensitivity!

    Posted 05.07.2008 at 6:04 pm

  21. Thaxt said:

    As general guide to tweaks, modders should try misbiasing this pedal all over the place – just small resistive changes can yield amazing results.

    I guess the same holds for the deliberate misbiasing of any trannies on just about any classic pedal that uses them. Small increments @ a time, subbing pots into circuits,& truning them a bit @ a time, playing your axe thru the breadboaded circuit, can be really productive.

    I sliced a small RS project box in half, mounted a 1/4″ phono jack into a hole drilled each, & mounted these on either side of my breadboad layout,one side going in, one out. Hence, I can just route my axe into the circuit, make changes, & just play to check out what each sounds like as I’m modding.

    I’ve ended up using 6-position rotary switches – or extra pots – to make certain misbias-resultant uniquenesses onboard into some mods.

    Posted 05.07.2008 at 6:15 pm

  22. Thaxt said:

    Further BMP adventures:

    I’ve started using MPSA13’s for all trannie positions on my current breadboard mod. They certainly yield gain – a transient impact reminiscent of the original. As well, I’ve bounced trannie types ‘back & forth’ , A/B’ing them by ear, asa well as voltage/gain.

    2N3904s actually are pretty good. I can see why the S Pickle makes use of them successfully. 5088s are noisy, 5089s, less so. The 5133’s sound very clear,but, somewhat lacking in gain…& possibly (by ear), bass. I might try some resistor bias modding w them. The MPSA13s, so far, are coming closest to early BMP sound-level.

    Hum is a problem w the MPSA13 setup. I’m currently trying JD Sleep’s type of mod of , placing a 2.2M *& other) resistors between then input point & gnd. This helps a bit. Much of the hum & noise on my mods seems to originate @ the input & Q1 stage.

    Anyway, after (too much) breadbd’ing, I had to go back & listen to the original to get a EAR reference point as to what makes it so distinct. I discern that a major plus/distinguishing trait is the prominent bassy impact on initial transients – almost like a compressor is put in front of the pedal!

    To add: this bass impact exists when using the utmost treble setting on the tone control. And, @ low vol levels, too.

    Musing along, I’m still thinking about the (SPT 87-103) transistors, but, also the GY 819 or 618 diodes. Can anyone tell me about the ability of minor Si diode differences to create this tonal effect? Hmm..Got to search for them.

    If I knew the SPT tranny gain specs, & the GY diode specs, I ‘d be ahead of the game.

    I’m now back to using IN4148 diodes, btw – I recommend them for early Traingle-Era authenticators…there is a definite diffrence w them, more like the ’71 BMP’s sound.

    Posted 21.09.2008 at 3:05 am

  23. Kim said:

    Hi, just built this, it was my first electronic project ever 🙂 No problems, the sound seems to be great, the tone pot doesn’t have such a drastic effect though… A little bit of hum, but I guess distrtion pedals always have some? Haven’t tried with synth sounds yet (I’m not a guitarist…).
    Substituted the 2N5088 transistors with BC550. Our teacher said they should be close enough. Also some of the caps were a tad different.

    Can’t wait to get home today and try this with some VST synths 😀 Gonna integrate this straight to my EnergyXT 😀

    Posted 26.01.2009 at 5:32 am

  24. direx said:

    hey great site gaussmarkov,try to use bc327-40, no noise- maybe need to rebias.

    Posted 27.02.2009 at 4:04 pm

  25. Thaxt said:

    Steve Daniels – of Small Bear Electronics – now markets a transistor designated as SE4010, indicates it is used by some for vintage BMP builds.
    It has an epoxy-dot case.

    I’m thinking more & more now in the direction of lower gain trannies for a BMP build.

    The Whisker Biscuit is a nice way of replicating a BMP. Looks very tweakable.

    Posted 27.02.2009 at 8:33 pm

  26. JohnnyWonder said:

    FS36999 were used in some early triangle Muff Pi’s they were just medium gain batch lot transistors that varied in beta from one end to the other. EH was known for using bulk parts with large tolerences ~20%. So there is quite a lot of variation. Playing the the bias is a great way to waveshape the Muff circuit.

    Posted 11.04.2009 at 7:54 am

  27. direx said:

    hi,i built this muff today and wow sound like the original triangle 1 version.i use c6 and c9 47n and 2n2222a transistors very close to fs36999.thanks

    Posted 11.04.2009 at 5:03 pm

  28. travlinman said:

    I’m wondering if you actually traced a known good triangle BMP instead of looking at schematics off the net since what I have seen doesn’t always end up like the schematics say in terms of the real values. The tolerences can be off as much as 20%+ even with their age these tolerences will become further apart also. It’s important to measure the values out of circuit.

    Posted 21.04.2009 at 2:12 pm

  29. gaussmarkov said:

    You are right. The source of the schem is really important. So I always give a reference and it is in the documents as well as in the blurb below the layout shown at the top

    Posted 21.04.2009 at 2:50 pm

  30. Thaxt said:

    I recommend visiting Runoff Groove’s Whisker Biscuit circuit. It’s a great takeoff point for modding a very effective Vintage BMP sound.

    Just tweak biases, caps, tonestack, & diode types by ear, & to individual taste. You can come up w a very individualized pedal sound w this one.

    There is, (to my ear,anyway) a very distinct difference in sound between 1N914 & 1N4148 diodes as clippers. From my A/B ing, the 4148s are dirtier, & edgier, & closer to the original BMP. There seems to be more intermodulation FX & intermod-type sonic artifacts w them. Harsher.

    1N914s sound cleaner, more ’rounded’. I ‘hear’ a bit more 2nd harmonic oriented, tubelike roundness w their use, a cleaner report. In just about any clipping circuit – trannie or op amp.

    While 1N34a’s yield a compressed sound w higher drive & gain, they also can carry a neat, uniquely characteristic static-y ‘spike’ in many builds – when you don’t drive them too hard. The Univox Superfuzz, Fender Blender, & (various) 1N34a laden Octavia-type builds sound this way.

    It’s only when you really push them that you come up w those very compressed , smoothed out ,less clipped sounds.

    Posted 17.09.2009 at 4:35 am

  31. Thaxt said:

    That BMP tonestack form is proving do do great things in adding tuneable midscoop sounds to my bass, btw. This is part of why bassists always enjoyed using BMPs for bass distortion.

    Taking off from the fact that the BMP tone control was bass friendly to begin with,I wnet looking for a clean bass tone control, minus the distortion. &, sure ’nuff, I ‘ve tweaked some good mods for adding a clean, tuneable, midscoop-to-pure lows bass tone control onto my bass. Doesn’t even need any compensating clean boost actually – I just turn up the amp or mixer volume.

    Posted 17.09.2009 at 4:44 am

  32. Frank said:

    Can you confirm you used a 100k pot????

    I bought them and they’re arriving but in other site I see the pot are 10k!

    Posted 23.10.2009 at 6:44 am

  33. gaussmarkov said:

    Yes, 100K. Good luck!

    Posted 23.10.2009 at 1:04 pm

  34. azeph said:

    Hi !

    I’m a bassist, and I really want to do a Big Muff. But this is a guitar version. Have you any idea for changing this circuit to make a Big Muff Bass version ? I think I must change some capacitors (and maybe some resistors too), but I don’t have any idea on which I have to use.

    Any idea ?

    Posted 11.06.2010 at 10:15 am

  35. Thaxt said:

    Hi, azeph,

    For a great bass tonestack, a la BMP, (using the schematic available on this site) , change R17 & 23 to anywhere between 5.6K – 15K. Vary & tweak this # to taste, of course. I started with 5.6Ks.

    Change C11 to .22uf. Then, change C10 to anywhere from .0068 – .01uf. An .0086uf cap here seems pretty good for me so far.

    Raising R17 & R23 in tandem seems to yield more ‘edge’ to the bass sound – lowering down to 5.6K resistors takes off edge, & makes for a round, lowpass bass tone, interactive w the TONE pot, as you’ll notice. This change is very interactive w tone pot’s position.

    I use a 10K, dual-gang pot in series w the 5.6K resistors, & this gives me a neatly variable ‘edge’ control for this tonestack as adapted to bass.

    For the TONE pot, use the usual 100K/L one, but, place a 47K resistor between either end lug, & where you connect the tonepot to the normal spots on the BMP circuit.

    Since I use this tonestack as an isolated bass tone control, I found that placing a very simple, 1 FET (or 1 MOSFET) low-gain, low distortion, clean boost preamp here, with a large electrolytic cap output – like, 10uf – 100uf, compensates for the signal loss the tonestack can produce. (or, just turn your bass amp up)

    Posted 24.06.2010 at 4:58 am

  36. Karter2000 said:

    Hi Thaxt,

    I love the idea for your tonestack, but I’m having a hard time visualizing it. Where does the dual gang pot and the usual tone pot go in relation to the circuit?

    Posted 04.10.2010 at 10:08 am

  37. Thaxt said:

    Hi, Karter –

    (wow, almost yr ago – sorry ; I haven;t visited here that much this past year)

    The 10K/L dual gang pots just increase the resistors that go to either end lug of the standard 100K BMP tonestack pot. So, the 5.6Ks & each of the lug pairs (2 & 3) on the dual gang are just in series w the 5.6Ks

    You’re altering the tonestack’s resistors 2 @ a time – equally, in tandem, using one control.

    I’ve found a neat tonestack for my Jack Casady bass as well, using the 500 oh,. I bridge a 330 pf cap across the circuit, placing a 56K resistor coming off either end of the 330 pf cap. The , I run each side (lugs 2 & 3A & 2 & 3B) of a 100K dual gang pot, w the 2 sides of the dual gang (meaning lug 2A & 1B) connecting at a midpoint.

    This middle point goes to a .15 to .18 cap, which in turn is sent to ground w a 5K/A pot. This pot acts to bring back in (or take out) mids. Rotating the 100K dual pot will give profound changes in bass tone, ranging from pure low end bass to treble laden highpass sounds & everything in between. Using the Casady Bass’ 500 ohm setting, this circuit makes for a way to imitate lots of bass types.

    You might have to tweak the values to conform to altering your own type of bass’s sound.

    Posted 10.03.2011 at 1:39 am

  38. Thaxt said:

    Hi –

    I have a question for gaussmarkov re: the 8V on Q3 of my BMP. Can you explain how this biasing yields the great asymmetrical clipping you speak of?

    It is a very overdriveable sounding Muff. that’s for sure. I was just playing some power chords w it, & w some added 3 way EQ on my mixer, it really can yield the hardest-hitting sounds of a huge, driven stack when set right. Even @ 9 o’clock Sustain settings.

    How can I go about duplicating this setup (voltage, etc) when breadboarding a muff duplicate mod?

    Posted 10.03.2011 at 1:48 am

  39. Karter2000 said:

    No problem! Thanks for your reply!

    Posted 31.05.2011 at 12:33 am

  40. Fs36999 transistors | Auctivastoreen said:

    […] gaussmarkov: diy fx » Big Muff Pi (Triangle Version)FS36999 were used in some early triangle Muff Pi’s they were just medium gain batch lot transistors that varied in beta from one end to the other. EH was known … Address: « Cifelli sandro Trackbackno comment untill now […]

    Posted 02.04.2012 at 7:50 am

  41. eugene said:

    hi, im having problems with my take on this project. it seems like i get a volume kind of effect when turning the tone knob. is this normal? i always turn the vol knob down when turning the tone knob up. could anyone explain or help me out with this (problem)?

    Posted 12.08.2012 at 11:10 am

  42. Canucker said:

    so this is the same version/parts as the dragonfly version? I may have missed the answer to that in my skimming of the comments….I built that one and must have flubbed something on the pcb (though countless double checks aren’t helping) so I think i’ll give this one a go! Time to etch!

    Posted 21.11.2012 at 11:05 pm