Green Russian Big Muff - modding

[Tune Tone]

so I check on this topic quiet a lot. read most of the comment on the layout page as well. saw this great PDF (which hopefully soon I will understand more)

http://www.kitrae.net/music/Images_Secret_Music_Page/BIG%20MUFF%20CIRCUIT%20GUIDE.pdf



still I am concerning these issues:

As for now my Vero board is built exactly as in the Layout of IvIark. I used silver mica  for the 3 500pf capis (since its the only one of this value that my supplier could offer for that time) the 100n are Greenies. I dont know if there is anything rather then that to let you guys know about...

I used quiet cheap and (what my suppliers website like to call -) universal silicon transistors of the BC550C type. they cost 15 Euro cent each.. so we are talking the most default transistor I could put there for now..
should I be on the search after cool germanium NPN transistors ? will they give more dirt, or is what I am describing can be achieved with these silicon tranis ?? - I forgot to mention DIRT and chaos clipping is what I am after

second issue - WHO EVER ASKED FOR ALL THIS AMOUNT OF BASS ?!?! I defiantly have to do something about the Tone knob functionality. Only once its turned all the way up you can slightly get a more mid range fuzziness that I am after.

3rd issue - can I do something about the flat / scooped / boost switch capis values for more presence changes ? If I get it correctly the bigger the value on these position the more mid it boosts ?? (since the 10n position is the Boosted Mids one..)

thank's for helping me. I am quiet new and understanding the theory of Muff circuits is currently what I am after !! craving for understanding !

best,
Assaf

THE LAYOUT - http://tagboardeffects.blogspot.de/2012/06/ehx-green-russian-big-muff.html

[Silver Blues]

I think I can help you out here

The Big Muff was designed and "intended" to use silicon transistors. I don't agree with BC550Cs being "most default transistors" as you say. The BC550 is actually a fairly "high-end" (if you can call it that) low-noise audio amp transistor. "General Purpose" doesn't mean "generic", it means "good for a range of applications". "Generic" (and also general purpose, actually) transistors would be something like a 2N2222 or a 2N3904, the BC550C certainly isn't one of them. Even though we use 2N5088 so much in effects, I wouldn't really call that a "generic" transistor either. The Big Muff is one of the kings of "dirt and chaos clipping" already, if you want more you'd be looking at a gated or "synthy" fuzz. These exist, but are extremely narrow in their range of applications. A voltage-starved high-gain transistor circuit of some description would be your next level of "chaos", but it would have nowhere near the massive sonic impact wall the Muff offers you. As far as swapping germanium transistors in, you could certainly try it, but I don't think it would accomplish quite what you're after, not in this circuit topology anyway, not to mention the variable bias headaches. You'd be directly affecting the exact property that gives the Muff its mojo if you start looking into modding it for germanium transistors. I reiterate, it can be done, but I'm not sure you'd like the result. High-hFE silicons are the order of the day.

All that amount of bass is great, man  it's the reason bassists like myself gravitate toward the Sovtek Green Muffs specifically. If you don't want that kind of bass content, you should be looking elsewhere than the Russian-era Muffs, which are by nature lower-gain and more bassy. What you want is a Ram's Head or Triangle-era (i.e. American) Muff. Your first order of business would be to take the input, output, and coupling caps down in value (these are C1, C4, C5, C13, C2 and C3 on Kit's guide). If you're using Mark's first layout with the 1uF caps then it's no wonder you're getting so much bass. If you still end up with too much bass, play with the low-pass filters (start by reducing the values of C10, C11, C12). Then if that's still too much, you play with the tone stack. Notice how the tone stack is really just a low-pass filter and a high-pass filter with a mix pot, so if you want less bass on the bass side, raise the cutoff frequency of the low-pass filter. If you want more treble on the treble side, raise the cutoff of the high-pass filter. This tool will help you work out exactly what you want.

Now, and if I understand you correctly, your issue is with what frequencies get clipped, not necessarily which ones get passed. In this case, what you want to do is play with the values of the blocking caps (C6 and C7). The larger the value of this cap, the more low frequencies get clipped and vice-versa. If you want a more middy sound you want to lower the values of these caps.

Mid content: You are correct, increasing the cap value will lessen the mid scoop. Just lowering the cutoff of the high-pass in general will lessen the mid scoop. You can put whatever values of caps you like on the switch, just remember that parallel capacitors sum the values.

Ask me anything, my pedal building knowledge is built on Muffs and they're my favorite fuzz.  Finding Kit's page is just about the best place to start with these beasts, so you're already ahead of the game. An older version of that page in a sheet protector has a permanent place in my project folder.

[rocket88]

just wanted to add to what silver said about the russian muffs, as i too have learnt most of what i do from my build of the green russian, it was my first build . mostly because i always wanted one, and like silver i am a bassist.

when i built mine i used the schematic posted on kitrae.net, rather then follow the exact layout mark has posted, and used NOS russian kt3102e transistors and KD521V diodes, just cause i was like why not. the russian green is MUCH bassier, smoother sounding and is considered to be low gain when compared to its american counterparts. this comes down to a few things. first, the massive size of the input and output caps, as well as the coupling caps. also the smoothness of the fuzz is due to the larger 470 or 500pf caps in parallel with the clipping diodes. this not only helps smooth the distortion, but also favors lower frequencies, ie: bass.

what you might want to do if you want to have more control over the mids, is instead of having a switch like mark put it, is to remove the switch and put in a mid control pot, like what's found on the ironbell, and other boutique modified muffs, so you can dial in exactly how much you want, and actually i want build another green russian with this exact mod.

as far as transistors go, high gain is a must >400hfe. in my experience i've found that when i use transistors that are lower gain that that the muff sounds sorta farty. in the my current russian muff i have and use the kt3102e transistors all have gain approx. 750hfe. silver hit it on the head about the bc550c's they are definitely on the higher end of the spectrum and make a good muff.

if you want to try one with Ge transistors check out the Earthquaker Hoof, which uses Ge transistors in Q2 & Q3. plus it has a mids control and started out as a green russian. i own an actual one, and it's a damn good fuzz, and great muff based effect, but for me and my gear, hands down the russian green for the win. and if you build it you get another muff, and you can never have enough muffs.

side not, is the switch making a big difference? cause with mine i original had miswired the switch and nothing really happened, but when i went back and fixed it, there is a MASSIVE difference between the flat/scooped/boost settings. to the point where the mids boost makes it cut through the mix like a hot knife through butter.

[Silver Blues]

More good tips Rocket. I'd forgotten about the Hoof. If you're into Ge I would give that one a try actually.
Iron Bell is also a kickass Muff, I've been meaning to build one myself. I'd say the IB is pretty gainy but there are ways to up it even more should you desire.

I purposely picked 5087s in the mid-300 hFE range for my purple Muff because I built it for bass, but even then it gets waaaaay hairy above half gain. I've even seen Darlingtons being used in Muffs so don't be stingy with the transistor gain. Even in the lower-gain variants it really is a lot better.

Nope can never have too many Muffs

[Vince]

The Earthbound Audio is great one to try. That way you have bass & mids to control

http://tagboardeffects.blogspot.co.uk/2012/09/earthbound-audio-supercollider.html

[rocket88]

I can tell you the iron bell is a monster. It's more similar to the rams head in tone then any of the other muffs. It works great on bass too. Has more sustain and kinda high end sounding to my ears, if that makes sense. More creamy then smooth, definitely think gilmour in comfortably numb solos. A winner in my book, but still for me it's the green russain, hands down is my favorite. I also think having the hfe as I do is a little over kill, but once I built it I've never even thought about changing a thing.

[alex.s]

A lot of great information has been already posted and explained at length, so I'll limit myself to adding that if you fancy having a play with the tnoe stack the trusty old Duncan Tone Stack Calculator (or TSC) is a great tool to do that. Start from the stock values and see how the graph changes by increasing or lowering values.

Also the coupling caps play a great role, you might want to lower a value to 47n (as seen on the Ram's head) to reduce the oomph, or play around, since reducing one value in different places will change the response, sound and distortion of the pedal (ie using the low value coupling caps before the clipping stages will produce a different distortion tone then if you reduce the cap AFTER the clipping)

[Tune Tone]

Thanks to all of you.. really
I read each message now and I am about to write myself some notes of what to replace and look closely.. definitely would have to lower to value of these so called coupling capacitors (the 1uf values..) and some several more other things.

For now.. I just filmed a short clip of me playing on teh effect. this is the only parameter I like.. when Tone and Sustain are almost turned all teh way up...
I kept on filming and did a more detailed observasion at each pot and the switch position to show the difference I still have to edit it and will upload soon as well.

Feel free to comment and let me know what you are thinking

best!
Assaf

[Tune Tone]

cant seem to embed the video.. so here it is >> http://youtu.be/ZWbZlG-00Vo

[rocket88]

Sounds ok to me. Not as bassy as I anticipated, but I'm sure in person it sounds different. Btw, I found this while searching some info on adding a mids pot. It's a ton of info on different mods to the muff. Might help you get it where you want it.

Also explains how the hfe affects the personality of the muff.

"Transistor mod: The Muff uses four transistors and the type and choice of these transistors will affect the sound greatly. The higher the gain, the more the unit will focus on the high end / treble. Some known examples:

The Russian Muff uses E type transistors (newer ones use BC549C's though) which has a Hfe of around 500. I used BC184's as a great replacement of these transistors.
The NYC Muffs usually use 2N5088's or BC550's with a Hfe of around 800.
The Little Big Muff uses 2N5962 with a Hfe of around 1500 - 2000."

I'm going to try lower gain around 500hfe to see what it does to my much beloved green russian.

[Silver Blues]

I agree on both counts. It's not wildly bassy at all (even though obviously most of the bass will get cut out from having the tone all the way up).

hFE relationship is true. Again, part of the reason I chose high-300hFE for my Purple Muff. Definitely you should give some different transistors a try, perhaps before you do anything else, as it will likely be the easiest mod you can make (you did socket your transistors... right? )

Also, if your multimeter has a transistor test function, measure the ones you have in there now as a baseline for experimentation. Won't help you at all if you put in 600hFE transistors and what you had in there already were 800, or something.

[Tune Tone]

Hey guys thanks for supporting

so I did 2 minor changes which to me already did a lot on the signal level side of things )still havent got to modding the tonal issues)

according to the Big Muff Circuit guid which became real common in front of my eyes this weekend. changing the 1K resistor that goes to the Sustain stage up to 3.3K which maybe gives it a little bit more air to breath and right ? I am not sure... what I do want though is wayyyy much more sustain. I would try even a 20K up next just to exaggerate and see the difference ...

the other resistor I changed was the one with 2.2K value going to the Volume pot to 1k. This gave a lot more volume and presence for the clipping.

The thing is that now the sustain works perfect just for the fat bass strings whenever playing a solo on the high ones you can hear it like its gated (maybe by the lo / hi pass filter in the Tone stage ???)
once I crank up teh sustain knob only then you can hear some of the high notes.

I am using the BC550c Tranis and yes, I did socket teh Tranis position.
Earlier today I tried as well replacing the diodes with red LEDs which was'nt that awesome, as well as placing 2N5089 tranis I got laying around. With these tranis I must say there wasnt much gain ... AT ALL!
I guess it need a different biasing of the voltage and other resistors attached in order to get the juicy gain out of them. Anyway it is.. everyone seem to recommend me the 2N5089 or even the MPSA18. Seems like those transistors wit hthe biggest Hfe are the better ones, aren't they ?
are they as well what I need if I am looking for a bigger Volume then all normal EHX muffs that you buy ? I mean one thing is for sure I can put a finger on - the muffs you buy are lacking volume !

still an unsolved issue which I am clueless of solving - how will it be possible to have the sustain pot not effecting the level of the signal ? it seems like every time I go beneath like 11 o'clock the signal is quiet clean and even way lower then the clean signal... and this issue I am having with the DBA Interstellar Overdriver I built.. I guess its within all layouts.. but why should Gain effect the Volume until the level it is completely left out ? how come an original EHX Muff is still delivering a signal even though Sustain and Tone are all the way down and there is nothing but the Volume which is up ??


a lot of question marks, though yet, I can smell the way to perfect modding soon..

best and thanks for the time and support,
Assaf

[Silver Blues]

Quiet Muffs? Now I know something's wrong. The Muff is just about the most ridiculously loud circuit I can think of. Thats one of it's main selling points. Are you sure your hearing is all right?

What you've done by increasing that 1K to 3K3 is increased the minimum amount of gain you'll get (i.e. when the Sustain pot is at 0), and simultaneously increase the maximum gain. I don't know exactly what you mean by "air to breathe". If you want more sustain, you'll be looking to up the gain primarily in the first stage.

Changing that 2K2 is exactly what you want to be doing to increase the volume. Increasing the 10K from Q4 to 9v will also do this (the gain of the stage is the ratio between these two resistors).

Gated, I don't think is proper. You will probably hear some octave overtones playing on the neck pickup around the 12th fret but gating... you will get a gainy but brittle sound with the tone up, which I suppose is kind of "gated", but if you're getting voltage-starved germanium fuzz-type gating then something is wrong. It could potentially sound good but isn't what the Muff circuit was intended to do.

Just keep trying higher and higher gain transistors before you do anything else, like I said it's the easiest mod you can make at this point and you never know if this will solve your qualms. If you're serious about exaggerating the characteristics I'd go so far as to recommend you pop a set of MPSA13 in there.

The Sustain pot will probably affect the signal no matter what you do. All it is is a voltage divider that sets the amount of signal that passes to the rest of the circuit, lowering signal = lowering output, regardless of where it occurs in the signal path. Again, this particular configuration has an extra resistor (which you've already played with) that prevents the signal from being attenuated completely when the Sustain pot is all the way down - and the tone shouldn't affect the volume much, except perhaps perceptively as a function of the frequencies it cuts and boosts. So having the Sustain all the way down and volume all the way up is really just using whatever clean headroom you have as a booster, the tone doesn't really factor in in this case (certain configurations lose a lot of volume at certain points in the tone sweep).

EDIT a word.

[rocket88]

I like my muffs like I like my women, LOUD!!! Hehe. But seriously, silver is right about muffs being quiet, they aren't. Usually they have WAY more output then you will ever need, and between the creamy muggy goodness if you slam the front end of your amp with massive output you get and ungodly wall of fuzz that calls to the heavens, beckoning the fuzz gods to come down, and bring the world to an end. I swear it is a religious experience to be baptized in the sweat, swear nectar of the fuzz lords. I did it once, just once with my mesa m6 and my god I still hear the heavenly trumpets of fuzz.

But on a serious note. I can't really add to what silver said as I was going to suggest the same. But, it sounds like you are coming along, and it will get there, don't give up on it. Everyone eventually has a muff they have to work at to tame. Hehe

[Tune Tone]

yo.. all good.. we are all relaxed right ?

what I ment is its only loud when really the volume knob is almost all the way up. doing a " A / B listening" baypassing the effect and switching it back on - is something that I did often jsut to compare the clean uneffected signal to the effect I built and I could note out clearly that I do need to have teh VOL knob right above 12 o'clock most of the times together with the Sustain to have it louder.

I guess now everything is almost like I want the real problem is still not much reaction to high notes + too less sustain I will listen to Silvers recommendations and see what I can improve.

I am mainly after this long sustain.. If I can get that the rest is just fine tuning. Im talking about playing a power chord and having it lassssst for a whole decade... even better would be to play a small guitar solo shaking with one finger on a high note and listen to the muff shakes with it.

Don't get me wrong, my hearing is pretty damn good and I know its already kicking Im just not there yet to find what I want.

best!
A.

[rocket88]

Haha. I think we're all relaxed, just trying to help. Lol. Btw, i checked out some of your other videos on YouTube, and I got to say I don't know why, but I love the BC Rich you got. Never a huge fan, but your sounds great.

[Tune Tone]

BC Rich ? are you seeing alright buddy ? this is a Gibson Les Paul

thanks a lot!

[Tune Tone]

Or.. do you mean the Green guitar on the Reverb effect demo ? this is actually  a Rickenbacker :D

[rocket88]

I thought a saw a black bc rich in one of your videos, maybe it was one of the other guys on the forum I do remember that green rickenbacker in the reverb video, which I'm beyond jealous of, hell I've been hunting for a rickenbacker 4003 bass in black that not going to cost me an arm or a leg, so seeing anyone that has one makes me beyond jealous.  

[Tune Tone]

Im on the same boat with ya man.. this Rick belongs to a friend of mine the guy who draw on my stomp boxes.. Im craving as well for a classic rick. at one point of my life I want to put a few hundred euros aside each month and in one year get it .. wet wet dream.