As a guitarist I'm always chasing "tone"... looking for those elusive sounds that makes the hair on the back of your neck stand up. Through the years I've been in many bands, notably a few Pink Floyd tribute bands, and during my tenure in these bands I struggled to achieve the sounds I was searching for, I got close, but there was always something missing. As you can imagine, playing lead guitar for a Floyd band is no mean feat, and takes a lot of planning. Each song is crafted, and moulded from many different effects, and colours... Back in the day I struggled to achieve these sounds by using run of the mill effects processors which for the uninitiated are very powerful digital effects units that have many different sounds that can be programmed and stored in any combination. For example, I could program reverb, delay and distortion into a preset in the unit. During a performance I would tap a button with my foot which would call up that preset number, and in turn all those effects would come on at the same time..... That's layman's terms. Effects processors are great, I still use one but I miss the old days of "stomp boxes" as they give you the true sound of what David Gilmour did back in the day, there is a marked difference between a proper analogue pedal and a digital "copy" for want of a better word. Where digital gives you a super clear signal and digital clarity that can't be put into question, true analogue pedals give you the warmth and dynamics that digital just can't give you. When you're playing Floyd you really need both as through the years David Gilmour has embraced both old technology and new technology (just looking at his enormous guitar rig demonstrates this) and that was my issue back in the old days....... I didn't have both, I just had the digital processor. 3 years ago I made the decision to turn my back on music.... I sold all my equipment except my guitars, and decided that I'd retire from playing in bands, my wife said I was mad and would regret it, needless to say I said "No i won't".... How wrong I was.


3 Years later, at the end of 2016 I was climbing the wall as I was missing playing. I realised that i was wrong and she was right. I now think I was just in a rut, and needed a break. Anyhow, I decided to replace all the equipment, but this time do it properly. I've now rebuilt my whole stage rig to incorporate both modern technology with the digital effects processor, but also have an elaborate switching system so that I can run old school effects pedals with the digital stuff simultaneously. I can now stretch my legs and build these pedals that should nail the sounds I've been chasing for so long... So far I've been happy with the results and as these blogs go on the builds will get ever more complex. I've started off easy with the fuzz face and the power boost which were fun pedals to build, and later on I'll be getting into the realms of modulation pedals like the Uni-Vibe the Phase 90 and the Electric Mistress. All 3 of these pedals (With maybe the exception of the Phase 90) will be a challenge as they are technically far more difficult than most out there, but I'm sure with your support and guidance i'll succeed and we'll have fun along the way. I still need that damned Oscilloscope!


Back in the seventies when Pink Floyd were pretty much turning everything they touched into gold, David Gilmour's guitar technician Phil Taylor presented David with a pedal that would forever shape Gilmour's sound from 1977 onwards..... This pedal was the Big Muff Pi manufactured by Electro Harmonix (EHX).


Up until then David had been using the Fuzz Face on pretty much everything from when he joined the band in 1968 (he used a Germanium Fuzz Face at this time), and then moving onto the Silicon Fuzz Face in the early 70's due to the instability issues with Germanium transistors. The Fuzz Face helped sculpt his sound throughout this period, and when Phil Taylor joined the band as Gilmours guitar technician in 1974 he started making suggestions to David as to possible improvements to his sound. Phil Acquired a 1973 version 2 Big Muff for David in 1974, however he didn't use it straight away, and it was shelved until around 1976 when Pink Floyd started writing and recording what would become the Animals album. He then tried it, and used it to huge effect on the Animals album, and the accompanying "In The Flesh" tour.


When i started this venture of pedal building, I had my sights set on building the two "Holy Grail" pedals, the Electro Harmonix Electric Mistress which hopefully will be the subject of another build in the future, and the Electro Harmonix Big Muff Pi. For me this pedal signifies everything about David Gilmours sound from 1977 to the present day. Used in conjunction with a Colorsound Power Boost and a bit of delay the sound is huge, and for guitar solos just sounds epic.


There have been many different permutations of the Muff since it was first released... Far too many to be honest. They started in 1969 with the "Triangle" Big Muff so called because of the shape the controls were in, this pedal started out being made totally by hand point to point soldered on perf board, they then introduced "proper" PCB of sorts, the triangle had at least 5 circuit variations between 1969 and 1973, that was followed by the "Rams Head" Big Muff, so called because of the little picture on the front of the enclosure looks apparently like a sheep... Then you have what I call the "Modern" NYC Big Muff..... All these share the same basic circuit and PCB, however due to availability of components, values were changed, substitutions made and the sound therefore changed between versions, and indeed in the same run of pedals. Basically, with vintage Big Muffs you can have 2 that were built on the same day, and they can sound different.


You can learn more about these pedals by visiting Kit Rae's excellent Big Muff Page This is probably the best resource on the net for all things Muff. he has managed to list pretty much every schematic, and permutation of the Muff from the very first Triangle pedals that were soldered point to point on perf board, right up to listing some of the better clones and boutique pedals there are out there. This site goes into far more detail that I will here, and for those that are interested it has the schematics...... You'll be able to see just what changes were made to the circuit over the years, what values changed etc........ This is pretty much the single best resource and was the starting point for my David Gilmour Big Muff build.


"Triangle" Big Muff   Rams Head Big MuffModern NYC Big Muff"Civil War" Big Muff



Everyone has their own favorite, some like the triangle, I particularly like the Rams Head (but there's more to that in a moment) The modern is best left undiscussed .... I'm not a great fan, and the sound is really nothing like what I would call a Big Muff. For a period of time in the early 90's they were made in Russia, by a company called Sovtek. Sovtek made these Muffs with so called Military grade components, these are now fairly sought after as they aren't made in Russia any more. The build quality wasn't the best, and some of the components like the jack sockets were truly awful quality. One of the more well known Russian Muffs was nicknamed the "Civil war" Big Muff on account of the font and colour scheme they used on the enclosure, this was used by David Gilmour throughout Pink Floyds 1994 Division Bell tour instead of his old Rams Head.


The cost of a new "Modern" NYC Big Muff is reasonably priced at around £80, however when you get into the realms of the vintage Big Muffs you might as well have a blank cheque. Cost wise the value of these things has sky rocketed. There was a "Violet" Rams Head that recently went on Ebay for $2000 (Check this link). The joke is, they pay this money because they think they're getting a rare pedal, the truth is every Big Muff during the 70's was different to the next. No 2 muffs are the same, this is due to the "slap dash" way in which component values were used... If they didn't have a resistor of the correct value they'd just solder in one close to it. This happened all the time, and by the end you had a pedal that sonically was different to the previous one, and different to the one before that, and before that... and so on and so forth. Kit Rae has conducted some A/B testing home made Big Muffs and just swapping out the transistors, the results were that the transistors don't appear to have a detrimental effect on the tone shaping of the pedal... It's more to do with the caps etc.


In 1976 David Gilmour had started to use the Big Muff, but he'd also started to have talks with bespoke effects board builder Pete Cornish. Pete Cornish is a British designer of electric guitar effects and other electronic musical instruments. He is mainly noted for his elaborate fully custom guitar pedalboard systems. He has worked for Paul McCartney, of course David Gilmour, The Who's Pete Townshend, Lou Reed, Tony Iommi of Black Sabbath, Brian May of Queen, Mark Knopfler (as well directing some Dire Straits videos), The Police's Andy Summers, and many others.


Cornish has been described as "the inventor of the pedal board" and a key figure in the transition from single effects pedals to the development of multi-effects units. It's this multi-effects system that caught David Gilmour's eye, and he got Cornish to build for him his first effects board for Pink Floyd's Animals tour in 1977. This featured all his effects built into a custom board, with buffers etc introduced to the board to reduce RF and ground loops etc. Pete Cornish is fiercely secretive about what goes into his boards, and effects and schematic are not available for anything that he makes, they're retained by him and the effects have anti-tamper seals on them so you can't get into them. Anyway, the Animals board also featured some send and return sockets so that Gilmour could add effects to the board, this was how he introduced the Electric Mistress and the Big Muff to his rig in 1977. Later on, Pete Cornish would modify this effects board by integrating the Mistress and Muff directly into the board with the other effects as these two effects alone had started to staples of David guitar sound.


For those that are interested you can learn more about Pete Cornish and his history in electronics by visiting his site here Pete Cornish


There is also an interesting interview with Pete about the "Animals" board here Pete Cornish: Pink Floyd Relics



David Gilmours "Animals" pedal board, build by Electronics genius Pete Cornish for the 1977 "In The Flesh" tour.

You can clearly see the Electric Mistress on the left and the Rams Head Big Muff on the right, on top of the board plugged into the send/return sockets.



There are many songs that Gilmour has used the Big Muff on, and to list them would be basically listing everything from 1977 to date. However I have to choose a few that I think show the Big Muff off in it's best light. to this end here is Dogs from the album Animals in 1977 (All 17 minutes of it!!), and Comfortably Numb from the album The Wall in 1979. I have also included Pink Floyds legendary live version of Comfortably Numb from Live 8 in 2005. This was when all four original members of Pink Floyd reunited for one night only..... This version of Comfortably Numb is pure Big Muff during the long solo at the end. It also shows just how damned good this band are even after all these years..... Not bad for 4 pensioners. They certainly showed the younger bands at Live 8 how to pull off a live performance.


Dogs - Animals 1977


Comfortably Numb - The Wall 1979


Comfortably Numb - Live 8 2005


David Gilmour to this day famously uses a 1973 Rams Head Big Muff, but don't for one minute think that you can call up a 1973 Big Muff schematic and make one exactly the same, as you can't. A simple glance at Kit Rae's web site will tell you that in the Rams Head version there were at least 8 or 9 different permutations, and differences of components over the build period, and they're just the one's we know about. This means that we just don't know what component values are in Gilmours pedal. Years ago in the late 70's David Gilmour bought a second Big Muff as a spare and it didn't sound like the first one he already had so he had to get Phil Taylor to open it up and basically change components to something near what was in his original pedal so they would sound the same, they are that variable. Kit Rae is a huge Floyd Fan, and he's tested many Big Muffs, so to a certain degree we can say he knows what he's talking about. He's managed to whittle it down to one schematic that seems to tick more boxes than most of the others on his assessment.... This is a 1973 version 2 Rams Head Revision 3, and the basis for this build.... The schematic and PCB layout are below. This revision was a crossover of sorts between the standard version 2 Rams Head and the "Violet" Rams Head (So called because they changed the colour of the enclosure font to violet and in some cases blue in late 1973 early 1974).


KR_1973_V2_No 3 Schematic (GILMOUR).jpg     muff pcb.png


A detailed circuit layout was created by Kit Rae, which I've included below. This outlines the various stages of the circuit, and maybe goes someway to explaining how it all works together. The level of detail on kits web site is mind boggling and worth a nosy.


circuit layout.JPG


For this project I'll be building 2 identical Big Muffs, one for me, and one for my friend Chris Oliver who's a professional musician who tours around Europe and the United States with the band Chameleons Vox. He's a Gilmour fan and I offered to make him one free of charge, I'll get to present it to him at a gig hopefully later this year when they eventually decide to return to the UK.


I'm sourcing as best I can NOS parts, all carbon comp resistors, etc. There is however an issue with the 4 transistors, FS36999. There is a lot of hype about certain transistors that are more desirable in vintage Big Muffs than others. On the top of this list is the mysterious FS36999 transistor found in vintage V1 and V2 Big Muffs, which was almost certainly 2N5133 transistors with a custom mark. Modern 2N5133 transistors are not the same, and have current gains that are considered almost too low for a Big Muff, although some 1970s 2N5133 transistors measure very low too. For this build I have managed to source 8 tested NOS 2N5133 transistors with gold plated leads. These are genuine New Old Stock from the 70's never been used and guaranteed tested, I'm sure these are going to be perfect for this build, and likely the closest I'm going to get to the FS36999. They weren't cheap, but at £15 for 4 NOS transistors I thought it wasn't bad. They also look nice .



NOS 2N5133 with gold leads


The Bill of Materials for this build as per the schematic above. I'm building 2 pedals so these numbers have to be doubled. For my build i'm using 1/4 watt carbon comp resistors. Looking at the PC board, I now don't think they used 1/2 watt as they would have struggled to get them in the board in a lot of the positions. When you offer up a 1/4 watt resistor to the board the size looks correct. The diodes are an assumption as we don't know what diodes they used in the original Big Muffs. Kit Rae has suggested that 1N914 should be in the right ball park, so that's what i'm going for. Transistors with the FS36999 branding seem to be isolated to EHX products, so the belief is that they are merely 2N5133 transistors that have been re-numbered by EHX. However people think there is a certain "mojo" attached to these transistors, which is why Big Muffs with these in them go for huge amounts of money.



0.5w Carbon Composition Resistors QtyCeramic CapacitorQtyPolyester Film Capacitor QtySilicon Diodes TransistorsQtyPotsQty
2.7k1470pf20.1µf81N91442N5133 NPN Silicon3100k Linear3
560Ω10.004µf1FS36999 (Preferred)3



Boards just need etching now...... Element 14 did OK out of me this time around, luckily we have a trade account at work so I can buy anything I want from them and they just dock it out of my wages and I don't pay the tax, which is nice. Some of the resistors I had to get from the US as Element 14 wanted to import them for me from the US at a cost of £15 shipping charge..... For resistors that cost £2.50.


Luckily I sourced a supplier on the net ( that had these resistors and shipped them to me for around $3 economy shipping from the US which was much better. During my search for parts for these various projects I have noticed that there are components available in the US that aren't available here in the UK, but the killer is the shipping charge from a lot of these suppliers. West Florida Components and Small Bear are two I can think of that charge a lot to ship to the UK, Some of the Fuzz Face components I had to source from a supplier in Italy who specialises in vintage components..... We just don't don't seem to have that resource in the UK.... Anyway, that's my rant out of the way on with the build.


Now I just need to etch the boards now and drill them. As usual I have used the toner transfer method, and as you can probably see I had to re-touch parts of the trace with a sharpie where the track hadn't transferred properly onto the copper. I'm thinking about changing to a different method.... When I was having the issue with the power boost I was corresponding with Ian Dempsey in Australia and he recommended trying the blue Press'n'Peel transfer films. Although expensive, they are supposed to be more reliable and consistent. You can probably see by the PC board that it appears that the pots are board mounted. They were on the the original pedals, but I need to think about whether I'm going to try and do that, or just simplify the build and mount the pots to the enclosure and just wire the pots to the board in the normal way.




Part 2 will be posted soon detailing the etching, drilling and populating the board, then testing the effect in an amplifier. Finishing off with the enclosure and the decal then a proper demo in my stage rig.



Top credit goes to Kit Rae for the images and some text etc.... Not plagiarized, and hopefully it's fully understood why. A lot of them were PDF's and I couldn't link to them properly.

You can visit his excellent web site at  The Big Muff Pi Page