Mutagen Fuzz…

[Coda]

This one showed up today, and was the only thing on hand that I could build without placing a parts order…or so I thought. A bit of background: I first discovered the Os Mutantes circuit last Summer sometime. Fast forward to a few weeks ago, and I was super excited to see the Basic Audio variant available here. I ordered it on Sunday (along with several other pcbs), and it arrived today. I wasn’t sure if I could built it, since there are no build docs, and was happy that, after looking over the PCB, it looked like I had all the parts I needed.

Not many parts in this one. I placed the first component…I think it was a 4k7. Next component to place: 3M3. I grab my 3M3 drawer and pull out a component. I stopped…the bands didn’t look right. Popped it in my tester: they are 3k3, not 3M3. Ootz. Looking a bit closer, there were a few components I was short on. No BC549B (I do have C, however). I settled on 2n5088. Oh well. A few sockets later I was ready for substitutions. The 3M3 became two 1M5 resistors in series. 4n7 caps because 3n9s that measured almost 4n2. I socketed the diodes too cause hey, why not?

I started this at 2pm this afternoon. At 4pm I plugged it in. It was a bit strange. Sounded kinda weird. I decided to replace the 5088’s with whatever else I had on hand that came close to BC549B. Settled on a trio of 2n2222 that all measured in the mid-200’s.

This is a really cool circuit. It definitely is a vintage 1960’s feel, but with way more versatility than most 60’s fuzzes. You can dial in OD/Distortion tones, raw splatty fuzz, or buzzy goodness. I was pretty impressed, and I didn’t even really get to know it yet.

Anywho, here’s a gutshot and a rough demo vid. No artwork yet because I’m working on that…

 

[fig]

Tasty! Decided against the 3m3 on the last page?

 

[Feral Feline]

I've already got an Os Mutantes type board, but still considering/wondering whether to get the PPCB version...

 

[MobyOctopad]

Ooh, is that Fuzz Dog's Mutantes Fuzz, or is there another take on the Regulus VIII out there?

 

[phi1]

This build is pedalpcb mutagen, based on basic audio mutant fuzz. Probably similar but slightly different from what can be built with the mods on the Fuzzdog pcb. I think clamp is the clipping diodes, saturation is probably blending in a larger input cap for more bass. No build docs yet to see what’s going on exactly.

 

[MobyOctopad]

Shit, sorry, should've replied directly to Feral Feline when asking about the other Mutantes board, but this is super helpful too!

 

[Feral Feline]

Shit, sorry, should've replied directly to Feral Feline when asking about the other Mutantes board, but this is super helpful too!

I've got the MadBean one, maybe even have two of them, I can't remember — one for sure, "El Guapo", later renamed "LETFA".

Discontinued but you can still download the LETFA build doc and compare it to PPCB's, see if there's anything worth a mod.

Now back to Coda's regular scheduled Mutagen build report...

 

[gila_crisis]

I've ordered the PCB, and looking forward to put this together, as already years ago I got interested into the Basic Audio original (David Torn was the pusher).
For transistors I'll try some BC183 and BC239, as I have a lot of these at home, which I used back then (with very pleasant results) in Big Muff clones.

 

[gila_crisis]

Here it is my Mutagen fuzz!
Wonderful, super vintage and doom/sludge fuzz. Now I understand why David Torn likes this one a lot!

Report to my build: I used the transistors I had laying around in my workshop.
I found this circuit to be very picky about transistor and hFe/gain, especially Q1/left and Q2/center: I first tried few BC183C, BC239C, BC550, or other high gain I usually use in BM and such, and I had a hard time making this circuit to work with these (with fuzz all the way up, I had no sound coming out of the pedal, like the transistor gain was too high and was choking the circuit). Then I found some old BC107A and BC107B and finally with those I got a wonderful sounding fuzz!
Q3/right on the other hand seams to be the easy spot: there also a MPSA18 was working very well. In then end there I put a BC109C.

It was a trial and error process, but I can't tell you the HFe of the transistor I used as I don't have a multimeter with a transistor socket.

 

[andare]

The original has a switch for a small input cap. It's on my breadboarding list. I want to make a step by step tutorial for myself and publish it here. Can't find the time right now.