Big Muff total gain

Posted by JaviCAP on Nov 10, 2014; 1:27pm
URL: http://guitar-fx-layouts.238.s1.nabble.com/Big-Muff-total-gain-tp15131.html

Hi mates,

As you know, the Big Muff is one of my favourite pedals, and i've built tons of them and own a few versions.

We have discused many times if the trannies hfe is key in the final gain / sound of the effect, and after many builds, I can confirm that the model / hfe of the trannies, is the less important thing in this board.

Let's see: the gain of a BMP is determined by the ratio collector- emitter in the three first stages (the last one is just to recover the output lost on the tonestack), so we just have to divide collector value by emmiter value of each stage, and sum the final values to get a "gain factor".

If we check a green russian, known for being maybe the less gainy big muff we find the next values:

Q1: C: 12k E: 390r= 12000/390= 30,75
Q2: C: 12k E: 390r= 12000/390= 30,75
Q3: C: 12k E: 390r= 12000/390= 30,75

Total gain factor= 92,25.

Now, let's see the most monstruous gain Big Muff, the first version of the Triangle (besides, originally built on perfboard :P)

Q1: C: 39k E:120r=  39000/120= 325
Q2: C: 10k E:120r=  10000/120= 83,3
Q3: C: 39k E:120r=  39000/120= 325

Total gain factor: 733,3

Of course, there are more components that affect the total gain of the effect. but let's say that 95% of the total drive, comes from thjis point.

I've built this weekend the Triangle V1, and really, the gain is absolutely massive. I've used 2n5088, BC550C, BC109C, 2N3904, ME4003, and believe me: the sound was nearly exact with every different trannie used. I even put one different in each position, with same results. Had to use MPSA07, extremely low gain (between 80-90 hfe), to get a farty and with few sustain sound.

So, from my experience, while using > 300hfe trannies, the Big Muff will sound great. Don't forget that the Swollen Pickle is just a tweaked Big Muff that uses 4x 2N3904, and it's a really harsh and high gainy effect.

By the way, for Zach and other bassists: if you love the Green Russian, just try the Triangle V1, you'll be amazed. The brutal gain factor + the intensive use of 1uf + 0.68uf caps + 27k tonestack resistors, get the most gainy and compensated between bass - mids -highs that I've listened, even thought is go high gain that can become a bit muddy on guitar.

J.