Pi All Around - Two Unique Versions of an Ubiquitous Pedal!

The Big Muff Pi, originally designed by Mike Matthews and released by his company Electro-Harmonix in 1969, is one of the most ubiquitous pedals ever produced. Combining elements of both distortion and fuzz with variable sustain, the Big Muff has been produced in a dizzying array of varieties over the years. Many of the variants were a result of EHX simply changing the value of the components willy-nilly during the production run. When Electro-Harmonix went out of business in 1982, clones and copies exploded on the scene, and Mike Matthews would re-open shop in the USSR under the Sovtek brand name and begin re-issuing his designs in the early 1990s. Matthews would bring production back to the US in 2000, and numerous new editions of the pedal have been released since then. If you're interested in the history of this great pedal, there are several great references, but one of the best is Kit Rae's page. 

Aion FX offers the Halo, which is their trace of the Big Muff. The only change is a mid-range switch that provides three mid-tone options: stock, flat, and boosted. Otherwise the circuit is a completely faithful tracing of the original. A spreadsheet of 18 different versions is included so you can target any variant with your build - or play around and develop your own recipe. At this point I've built two versions which are included in this entry, a Ram's Head '73 Gilmour and a Civil War / Red Army version. Depending on what transistors I'm able to find, I may go back and build other variants as well, as these are a lot of fun!

In the photo above you can see the enclosures for both of my Halo builds. The enclosure on the left is the Gilmour version and the one on the right is the Red Army version (obviously, I guess!). Both of the enclosures are sourced from Tayda. The Gilmour was powder coated silver, and I added my own home-brew decals made up with my laser printer. The Red Army version came unpainted, and I primed and painted it using AK Interactive 4BO Soviet Green paint. The decals were custom made by Scumb4g Kustoms - who I've used for a LOT of other projects (non-pedal). The Gilmour version is just using some standard knobs I picked up from Love My Switches, but the Red Army version is using some vintage Soviet bakelite knobs!

The PCB for my Gilmour build is pictured above. As finding actual FS36999 transistors is essentially impossible, I went with 2N5133 transistors - which many people believe are actually the same as the FS36999. At this point I didn't have my Atlas to check the transistor leads, but I did manage to find a copy of the original spec sheet online which allowed me to identify the base, collector, and emitter successfully. I also went with Allen-Bradley Carbon resistors, mostly for aesthetics. I wasn't able to find enough true ceramic capacitors, so I went ahead and stuck with film capacitors for this build. If I ever do another early one, I may try and find ceramics.

Unfortunately I wasn't able to get a good photo of my Red Army build before I put it into the enclosure, but you can see it nestled in its permanent home above. For this build I pretty much went with 100% modern components. I also picked up some "green and white dot" modern KT3102E transistors to complete the build. If I had to do it again (which I might) I'd go with all early configuration parts (as much as is possible) - sort of like the photo from Kit Rae's page (below).

Russian built Big Muff - source: Kit Rae

Of course, that being said, actually finding vintage parts from reputable sources that work properly can be a challenge. I have a lot of other builds ahead of additional Muffs at this point, but if I come across the right parts, I'm not going to let them walk past.

As to the rest of the enclosures, they're completely standard as far as Aion FX builds go - normal In / Out and the standard 9V DC connector. Both of these include battery snaps, but at this point I'm not actually using too many batteries in my pedals. I have a couple of vintage style builds that may just have a battery coming up, though.

If you're looking for a first pedal build - one that's simultaneously user-friendly, but with as many options and complexity as you'd like to add, the Big Muff is it. In its stock configuration it's a great starter pedal - and Aion FX and many others make ready to build kits. However, you're equally able to start with the PCB and a spreadsheet and begin an epic quest for bespoke components to assemble your dream pedal!