I got Muffins on the Protoboard!

Song Naga

Song Naga

Member
Hi all, I kludged together one of the PedalPCB Protoboards a couple weeks ago and figured I'd put it through its paces after building my first Muffin Fuzz pedal about the same time and finding that there are all sorts of versions of the build in the BOM. I opted to build a Green Russian for the PCB I ordered, so I tossed a Civil War version on the proto board.

I'm not very practiced at breadboarding, and had to pull the circuit apart and move the transistors to different areas to isolate each section a bit and make things easier to troubleshoot. I wound up getting a 'mighty fine' sound up to the tone controls, and had to pull the ass end of the circuit apart a couple of times before I finally got things in the right place, but when I had it I knew that I had it! My last problem was I had a 100n cap in the tone circuit's LPF rather than the called-for 10n cap, which was producing a muddy and low volume result at the pedal's output.

I know I'll probably inevitably build most or all of the versions into 125B pedals now that I know that I can, but in the Meantime (Helmet reference) I think I'm going to build each version on the proto board to break it in and get some practice. Maybe by then I'll know a thing or two and will start tweaking things to craft some sort of custom muff! I'm also enjoying other Muffin-related posts and related rabbit holes (https://www.kitrae.net/music/music_big_muff.html).

1761708286930.png
 
Haha, I'm literally doing the same thing at the moment


PXL_20251028_110213559.jpg

This is the green russian, Its working but I need to troubleshoot very low volume - My plan is to build this, get it working, then build the civil war, a/b them, and then build the next one and a/b them til i choose my favorite. I've made mine very bunched up which I've already realised is quite dumb.
 
Sweet! I found that spacing out the transistors helped me understand and troubleshoot the circuit hugely. Each one has 4 - 8 additonal components to support it, so there's plenty of room to add those around the transistors and then jumper between each 'stage' of the circuit. This approach helped me identify my low volume at output problem, which was due to a wrong value capacitor in the filter. If your signal sounds great going into the filter but crummy coming out of it, maybe you've done the same?
 
yeh need to find the time to go over it again, i was doing my usual thing of trying to put it together in a rush.
 
I FINALLY got the issue with my muffin circuit sorted this morning: I had a 12k resistor between the collector and ground on the 3nd clipping stage when I should have been a 390 ohm resistor. It sounds much better now, with an output level that matches my Green Russian build. I subbed 390pF caps for the 430pf clipping caps throughout the circuit since that was what I had on hand.

The circuit sounds a good bit brighter and a bit 'harsher' than the Green Russian. Comparing the BOM's it looks like the only difference between the circuits are the clipping cap values and a single resistor between +9V and the emitter of the last transistor in the circuit before the audio output. I totally expected the filter section to have different values, but they are identical. I'd say the top 25% of the filter pot is useless, just waaaay too bright and scratchy. Reminds me of my old DOD Thrash Master pedal from high school, which my guitar playing friends all mocked because it sounded like "raking leaves" when the filter and gain were cranked.

It's pretty amazing to hear what a difference all of 4 components makes.
 
I really struggle with the muff tone stack. I totally agree with you, too much treble. I usually change the values to give a flatter response.
You can mess with it here to get a visual of the frequency response and try stuff.

tonestack.yuriturov.com
 
You must log in or register to reply here.
Back
Top