JHS/EHX Big Muff 2

[owlexifry]

schematic:



layout:



(unverified)

[owlexifry]

Verified.
(assuming schematic is accurate)

[IvIark]

Nice job and a cool looking build. Thanks for sharing 👍🏻

[owlexifry]

cheers!  
no worries \m/

[fx-fidden]

Here's the new modern schematic:
https://docs.pedalpcb.com/project/RedMuffin-PedalPCB.pdf

[fx-fidden]

Modding a bit this verified layout above we can include the power supply filtering and voltage reference.



That should make the pedal a little less noisy and reduce motorboating in some settings.

[fx-fidden]

JHS Big Muff 2 version. NOT verified.

UPDATE: NOW VERIFIED! (Thanks ivivan)

[ivivan]

There's an error in the circuit. The output from the second gain stage is from pin 2 of IC2. It should be from pin 1. Otherwise, everything is correct. It's done and it works. Assembled on a breadboard.

[fx-fidden]

I'm glad to see you built my layout, and on a breadboard!  (I called that board a protoboard.) And thanks for sharing your layout.

I want to finish some other projects, but I can't wait to build this one too.

How do you find this effect?
What about the noise? That's the thing I'm most worried about.

[ivivan]

There are no noise issues. And without the enclosure, there's practically no noise, even with the sustain and volume cranked up.
It sounds very similar to the EVX Big Muff I used to have. But I think it sounds less aggressive, a little more gentle. :)
The enclosure will arrive in a few days, so I'll test it out more thoroughly. Before the case arrives, I'm thinking of adding a Tone Bypass switch. Like one of the older Big Muff versions. I liked the sound of that one—no midrange cutout and higher gain.
P.S. Please correct the error in the schematic in your post from February 18th.

[fx-fidden]

I updated the layout with the VERIFIED one.

I just watched some demos, I suppose this sounds more doomy and bloomy, rather than heavy distorted. It probably also lacks a bit of high-end unless you turn the tone up.

I’ll try some mods to make it brighter and less bassy, adding a few switches.

[ivivan]

Excellent!
I don't like too many switches on the pedal. So I changed my mind about installing the Tone bypass switch. But I'm going to add a B50k potentiometer in series with R13 in rheostat mode. It will be a MidBoost. And maybe I'll use a Tone B250k potentiometer instead of a B100k.

[fx-fidden]

Cool!

Just a small value correction: the capacitors are 500pF in the original schematic, while JHS uses 470pF.