Electro Harmonix Big Muff Pi

There are lots of variants on the Big Muff. At the time I’m writing this, Electro Harmonix alone has 15 different models available on their website, and countless other builders have done their take on the Muff. The original Big Muff Pi was introduced in 1969 and even of that pedal, there are numerous versions that have been made in the last five decades.
The one I’m looking at is a NYC reissue from 2010, I believe.

It’s simple and it is big. There is nothing subtle about the whole affair. Looking inside, it’s 90% air.
You get three knobs, named Volume, Tone and Sustain and a foot switch. The haptic and acoustic qualities of the foot switch are remarkable. Not only does it activate with a very tactile click – one you can feel through a snow board boot – but also a loud one. The huge enclosure gives the switch a lot of room to resonate. If you were playing an acoustic gig in a coffeehouse setting, this pedal would indeed be too loud to step on – but that is not an issue. I doubt anyone would bring a big muff to a coffeehouse gig.

There are pedals that are capable of fuzzy sounds and there are pedals that can be considered a real fuzz once you turn the gain high enough. The Big Muff Pi is a fuzz no matter what you do.
My starting point was Tone and Sustain both at zero and Volume set to unity, about noon.
This passes signal, and shows that the Sustain knob is not just a gain knob. It feels to me like while it does somewhat limit the clipping in lower settings, some of that could be filter based and not purely gain based. I have no clue if that’s the case, but it feels like it.
The tone knob gave me the impression of a tilt EQ thing, at the brighter settings it did cut bass by no small margin, but with all the clipping and harmonics going on, it’s hard to guess what it does exactly. Left is darker, right is brighter seems sufficient for a description, though.

Starting with everything turned down the Big Muff Pi remains a fuzz pedal. This is nothing you can use as a clean boost in a pinch. When you run through the travel of the Sustain knob, there is a massive difference around 8 o’clock, that’s where the fuzz really wakes up on the first few notches from zero to that point, the sound you get is a bit starved but not at all unpleasant. When you reach that 8 o’clock threshold you get flooded with harmonics and from there, the character stays the same, you just get more of it. Even at the lowest settings, a heavy compression sets in. The pedal is somewhat reactive to how hard you play, but you only influence the level of dirt, not the output volume.
Crossing the 8 o’clock threshold means waving good bye to note separation. You get a sludgy wall of fuzz. Changing a minor chord to a major chord yields some audible difference, but the root note along with the octave generates so much sizzle, the underlying notes nearly disappear.
Running the Big Muff without any safety precautions feels a bit like torching the room with the audio equivalent of a WW II flamethrower. There is nothing subtle about this. Running the Big Muff into other pedals or the amp can yield much more manageable sounds, when you set your EQ right for the application.
Let’s get back to the minimal settings. With both Saturation and Tone fully CCW, the pedal shows at least some characteristics of a low gain pedal. However, the distortion you get is absolutely even. The low B gets the exact same reaction a pinched 24th fret harmonic gets. The compression is, as already stated, quite heavy and the finer nuances of the timbre from the connected instrument are lost to the clipping.
There is a mid scoop going on no matter where you set the tone knob, this is baked in to the circuit and cannot be helped, which means the placement in a mix is not exactly front and center unless you ride the volume a fair bit higher than unity. Also, the generated harmonics work best if there is some sonic space for it to bloom – with distorted guitars and a heavy handed drummer, most of the sizzle adds to the band noise, but cannot be traced to the source easily.

The bass loss exists, but not in a worrying amount. You can absolutely run your bass into a Big Muff without needing to limit yourself to the bass specific versions.