Big Muff Pi tone bypass - quick mod gets the midrange back

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Issue 342 January 23, 2020

Blake shows you how to easily mod a Big Muff Pi tone stack to get the missing midrange sound back. With this pedal mod, you can simply flip a switch to get that great midrange sound, then just switch it off when you want that regular big scoop sound that the Big Muff is famous for. Great pedal mod that anyone can do to take their Big Muff Pi to the next level.

In this Trade Secrets video:
  • What’s missing in the original Big Muff Pi sound?
  • Compared: Big Muff Pi sound before/after the mod
  • Easy mod kit with instructions and parts

Video Transcription

[on-screen text reads: StewMac tools + ideas for guitarmaking]

Weekend project Big Muff tone bypass

Blake: This is the classic Big Muff Pie and it was used by one of my favorite guitar players, David Gilmour. I was messing around on his gear page and I learned that he used this on two of my favorite albums, Animals and The Wall. He used it in combination with other drive pedals, gave him a really great sound, but by itself I'm not super crazy about it.

Whats missing in the original Big Muff Pi sound

So the reason I'm not crazy about it is because of its mid-scoop sound that the pedal's famous for. The reason you're getting that mid-scoop sound is because of the tone knob circuit or the tone stack. Now as you roll this tone knob up, you get really tinny highs. It takes away bass to simulate adding treble, and as you roll it down, you get really muddy and it takes away treble to simulate adding bass. But you can mod the Big Muff to get all of that better range back, just like this one.

This one's had a switch added right in between the sustain and the tone knob. So when you activate the switch, you bypass the tone stack or tone knob part of the circuit. When you do that, you get all of your mid-range back or you can turn your switch off and you can have that regular Big Muff scoop sound. Listen to this...

Big Muff sound before/after the mod

Here's a normal Big Muff sound with tone control turned up [Blake plays his electric guitar with normal Big Muff settings] and then here's the mod [Blake plays his electric guitar with the mod kicked in]. To me, that's a great difference to have and it makes me twice as likely to use this pedal. I've never done a pedal mod myself, but I'm told that this one's pretty easy to do. I going to be using the mod kit that StewMac sells with these step-by-step instructions. This looks like it's going to be pretty easy. Hopefully don't mess it up, but I don't think I will.

Easy mod kit with instructions and parts

First, I drill a hole for the switch I'm going to add, then solder four wires to the switch. There's really not a lot of wiring to do. You unsolder the ground leg to one of the capacitors on the circuit board and do the same to one of the resistors. You'll add some heat shrink that comes with the kit. Then you attach the four wires from the switch, put it back together and let's give it a test.

[Blake plays his electric guitar with the Big Muff Pi normal and with the mod kicked in]




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