Muffin - Green Russian

[kylewetton]

When I built my first Muffin I had no idea that there were so many variants I could build (or that they even existed to be honest....hahah).

Some of you have been following my "Fuzz Journey" since I started building pedals and posting about them here. More like a taste test through time with some classics, and some modern fuzzes. I like them ALL hahaha, but there's still so much more to try. The Big Muff's are just super appealing to me tonally and my goal is to build all the "biggies" at some point.

With the first Muffin board I decided to start with the Triangle as it was (I think) the original. I love that thing! It's a close call whether it or the Gnat (Burns Buzzaround) would be may favorite fuzz. (Actually a very close third would be the SolaSound Hybrid Tonebender, but I digress, this post is about Muffs). Shout out to my main enabler @szukalski for turning me onto the Gnat!

Anyway, back to the Muffs. So all this interest in the BMP is one aspect of a larger story of chasing some of the Gilmour tones and gear.
There are other pieces to the puzzle but it's a fascination that's been enabled by the likes of @Big Monk and @music6000.

I'm still not sure I know exactly what a Green Russian Muff is except that it was made by Sovtek for a while during the Mig amp days.
But with all the chatter about it, I decided to try building that one next.

I actually had this enclosure drilled and painted and ready to go yesterday but that got bumped by my Mosfet Driver build.

I had a busy work day today and wasn't sure I would have much bench time, but I was chatting offline with @steviejr92 this morning and he was like "So what's on the agenda today?" Which got me thinking....."Man, I've already got the enclosure drilled and painted for the Muff and the parts ready to go....I can skip lunch and knock it out....." hahaha, so I did!

Aside from an initial unforced error which we won't dwell too much on........ (put the trannies in backwards.....and soldered them in ) it was a smooth build. I followed the BOM in the build docs for the Green Russian. The only subs I made was in using my vintage Telefunken BC239A's instead of 2N5088's. I didn't check the gains of the 5088's I had on hand but I'm pretty sure they're generally on the higher side. So I went through my stash of 239's and picked 4 that were all around 430 Hfe. I also forgot the 239's are backwards pinouts to the 5088's. I think I made the same mistake on my Triangle build but since I socketed those it was a quick fix. One this one, since I already knew I'd like these Telefunkens, I went ahead and soldered them in. So it was a bit of a pain getting the old ones out without melting anything and get some new ones in correctly oriented.

Oh I also decided to try Log pots instead of Linears that I used in my Triangle, I didn't like it for the sustain and swapped it back to Linear when I fixed the trannies. I think I'll stick with Linear for both volume and sustain my next one.

Definitely a different flavor Muff than the Triangle, to me it sounds warmer, rounder and smoother with less "bite", but loving it. I've fallen in love all over again with my PRS Vela since re-wiring it last week (un-doing all my trick wiring and pretty much restored it to stock configuration but with upgraded electronics.) And it sounds glorious with this pedal.

This is an "Army Green" paint color I ordered off Amazon. It's a lot lighter than I thought would be but I like the brand, it dried pretty fast but still scuffs easily. I may try a satin gloss or semi gloss top coat on it next time I use it.

Anyway, very cool build! Looking forward to the next one....!

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Egads! there's a crooked capacitor....!!! I'll need to fix that tomorrow.....
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Hey @MichaelW , coming in with a beginner question here. I noticed your transistors are installed backwards, i bought the 2N5088 from Tayda, are yours a different type of transistor which is why they're installed backwards or should I be following suit?

 

[szukalski]

Hey @MichaelW , coming in with a beginner question here. I noticed your transistors are installed backwards, i bought the 2N5088 from Tayda, are yours a different type of transistor which is why they're installed backwards or should I be following suit?

Did you read his original post? He specifically says that he is using different transistors with a backwards pin out.

 

[kylewetton]

Did you read his original post? He specifically says that he is using different transistors with a backwards pin out.

Hah, actually I had two tabs open. The Triangle build report and this one, both have backwards transistors and didn't realise I'd only read one of the build reports (evidently the one that doesn't mention why the transistors are backwards), thanks for pointing that out

 

[MichaelW]

Hey @MichaelW , coming in with a beginner question here. I noticed your transistors are installed backwards, i bought the 2N5088 from Tayda, are yours a different type of transistor which is why they're installed backwards or should I be following suit?

Sharp eye! Yes, I used vintage BC239's for both the Triangle and Green Russian builds instead of the 2N5088's. The pin outs are reversed.

 

[darwin999]

So let me return to this old thread for a question.

On this and several other threads, I've read @HamishR state that using lower gain transistors (e.g., 2N3904 instead of BC239) alters the sound, making it smoother with less harshness. So that makes me intrigued.

But after some reflection, I'm curious how this actually works - because seemingly it's not due to the reduced hfe of those transistors (I *think*). E.g., when I read through the ac gain analysis of ElectroSmash (https://www.electrosmash.com/big-muff-pi-analysis), the voltage gain calculations of all 4 stages are set only by the various resistors and capacitors - i.e., hfe never enters the gain calculations. In fact, no transistor parameters enters the gain calcs, which kind of begs the question why does the BMP even need a high gain transistor like a BC239/BC184/etc? So is there a different characteristic or parameter that leads to the sonic differences that @HamishR is hearing? I'd really like to understand this better - and/or understand where I went off course, lol.

Can any of you Big Muff experts help me understand this better? @HamishR ? @Chuck D. Bones ? Anyone else?
Thanks in advance.

 

[HamishR]

My "knowledge" is purely anecdotal. Chuck often kindly points out where I am wrong! Most of my observations are just that - observations. I have built Big Muffs with 2N5088, BC549C, BC550C and 2N3904 transistors (and probably others). I like the sound that the 2N3904s produce because it seems a bit creamier or something. It's not a night-and-day difference but I like it.

As to the why - well, you'd have to ask Chuck. Again, he may tell me I'm wrong. Doesn't bother me!

 

[darwin999]

My "knowledge" is purely anecdotal.

Hey, I totally believe you, and that's what got me thinking - and how I realized that I didn't understand something that's relevant and useful.

Hopefully Chuck or others can point me in the right direction, otherwise I may need to simulate some circuits in LTspice, and play with parameters.

 

[HamishR]

Mainly what I'm saying is that (a) I can be wrong, and (b) Chuck knows everything! I definitely don't.

What I really enjoy with this hobby is that it doesn't cost much (yet!) to try these things. If it sounds good it's handy to know why, but I can still enjoy the fact that it sounds good. Then I can ask Chuck why. I'm the guy throwing shit at the wall and Chuck can tell me why it sticks or not.

 

[Feral Feline]

So let me return to this old thread for a question.

On this and several other threads, I've read @HamishR state that using lower gain transistors (e.g., 2N3904 instead of BC239) alters the sound, making it smoother with less harshness. So that makes me intrigued.

But after some reflection, I'm curious how this actually works - because seemingly it's not due to the reduced hfe of those transistors (I *think*). E.g., when I read through the ac gain analysis of ElectroSmash (https://www.electrosmash.com/big-muff-pi-analysis), the voltage gain calculations of all 4 stages are set only by the various resistors and capacitors - i.e., hfe never enters the gain calculations. In fact, no transistor parameters enters the gain calcs, which kind of begs the question why does the BMP even need a high gain transistor like a BC239/BC184/etc? So is there a different characteristic or parameter that leads to the sonic differences that @HamishR is hearing? I'd really like to understand this better - and/or understand where I went off course, lol.

Can any of you Big Muff experts help me understand this better? @HamishR ? @Chuck D. Bones ? Anyone else?
Thanks in advance.

Somewhere in the miles of typed info on KitRae dawt-cawm, Kit mentions that some of his favourite sounding Muffs defied his expectations —
they had lower hFE transistors...

I seem to have found it...

BIG MUFF TRANSISTORS AND OTHER COMPONENTS

When I started collecting Big Muffs it was generally assumed that the best sounding vintage units had high hFE transistors in the 400-600 range. When I pulled all four FS36999 transistors from an exceptional sounding 1973 Big Muff in my collection and measured the hFE I found it ranged from 164 to 204. I also pulled the transistors from one of my Tall Font Green Russian Big Muffs and found they ranged from 200-250hFE.

...

Lower gain tranys are said to be smoother sounding than higher gain ones, and higher gain tranys are said to influence the mids and pick response, although actually hearing these differences is sometimes not an easy thing. Current gain of transistors should not be considered alone however, because the bias for the amount of gain for each clipping stage is set by the resistors coming from the collector and emitter of each transistor.

...

In a blind test, I could not pick out one over another listening to recorded samples, and differences I thought I heard changing them out using sockets were probably just my imagination. The only real difference I noticed was the transistor in the last stage. Different transistors and different hFE values seemed to alter the sound in that position, but it's a subtle difference.

I believe the effect different transistors have is minimal, but many pedal builders believe they have a large impact on the sound. That is why many of these makers screen batches of transistors to weed out the less desirable ones. Electro-Harmonix never screened transistors when they made the original Big Muffs.

...

I suggest not getting too hung up on the transistor type when looking for a vintage Big Muff though.
...
The other circuit components are much more important to the tone.

 

[darwin999]

@Feral Feline - thanks for that link. So it's subtle, and more audible w/ transistor shifts in last stages. And it might include peripheral issues such as unintentional bias changes when swapping transistors. So I need to play around, clearly.

 

[Big Monk]

Don't look past vFE of the diodes as well.