Adding Tone Controls to 2-Knob Fuzz Pedals

[iainpunk]

maybe this is a cool option, it is a ''body'' and ''tone'' knob, basically the knobs have these functions:
body] its a LPF that varies between 1.6kHz to 140Hz, it takes out the treble wherever you set it, but depending on the setting, it takes out midrange as well.
tone] this lets the higher parts of treble back in to the circuit, mainly above 2kHz,
if the body is set to the 140Hz and the treble to max, it creates a mid scoop of 18dB scoop around 900Hz, while increasing the body knob makes the scoop less deep and a higher frequency.
this is a useful tone knob for the more noisy fuzzes where you need to keep the low end intact to not drown that out with the high mids and treble

cheers, Iain

[iainpunk]

the circuit you posted last, the SWTC cuts and boosts trebble.


cheers, Iain

I feel that the standard SWTC only cuts treble.

yes, the normal SWTC cuts trebble, but he posted that one that cuts everything a few dB, and then feeds the treble back to 0dB or flushes it to ground even deeper!

[Vivek]

The standard SWTC does this :



I'm with you in that Fuzz and most distortion normally do not need post clipping treble boost.

They need cuts.

[iainpunk]

The standard SWTC does this :



I'm with you in that Fuzz and most distortion normally do not need post clipping treble boost.

They need cuts.

or mid scoop, which ''feels'' like a treble boost, so you can get that ''vintage fuzz'' tone which can really work in certain context, but it also has the bass/low mid boost, if that isn't present, it just sounds bad and fizzy, the bass gives the treble context!

[pinkjimiphoton]

have an adventure. math is fine for electrical engineering. they teach you to MINIMIZE distortion, not create it and maximize it intentionally.

its just not always necessary. i knows nothing, less than nothing, about "math" or doing stuff "right.

shit, i used to come up with ideas and just build 'em. then tweak on the fly. pretty much, i still do.

math is great for phase shifters and choruses n stuff, but fuzzes? if ya say so.

i say just do it. greatness awaits not in science with fuzz but application. often things WRONG sound GREAT, and you're gonna learn way more from mistakes than anything else. try them stupid ideas. make things wrong. bend the rules, hell, SHATTER them muthafuggas.

don't listen to anyone, including me. just freeking do it. and when ya get that sudden SCHA-WINNNNNGGGGGG you'll be like.... YEAH.

[debrad]

The timing Iain's "Tone+Body" suggestion is very interesting because I stumbled across two very similar ideas last night while digging into the BMP tone stack a little more.

The Beavis Audio Research pages (http://beavisaudio.com/techpages/bigmufftonecontrol/) lead me through the original BMP circuit and a couple of variants with the extra "body" control that seemed intriguing (especially since they can mostly be built right on the potentiometers which would save me some space inside the enclosure).

I then ran across a similar sequence of  BMP tone stack "evolution" on the amzfx site (http://www.muzique.com/lab/tone3.htm) which shows how tweaking a few components can shift the frequency response from the typical mid cut of the original BMP circuit with the tone control at noon to a mid boost with the same setting.

I'm starting to think this BMP-based combination of Tone+Body might be where I start first.  My next step then would be to see where I like it best in the Super Fuzz circuit.

[iainpunk]

have an adventure. math is fine for electrical engineering. they teach you to MINIMIZE distortion, not create it and maximize it intentionally.

not per-se, i apply a bunch of rules to maximise the noise in a fuzz, to break the sound completely in a way that is so illogical that ''just breaking rules'' wouldn't get you those results.

i say just do it. greatness awaits not in science with fuzz but application. often things WRONG sound GREAT, and you're gonna learn way more from mistakes than anything else. try them stupid ideas. make things wrong. bend the rules, hell, SHATTER them muthafuggas.

i respect your opinion, but i have vastly different experience, if you apply all the rules consistently, not just a few of them, you can get close to or exactly the thing you want. if you experimented enough to know what the rules sound like that is!
i guess that for me, coupling the rules to sounds streamlines the design process to get results i seek out.

the way you write ''sounds'' really californian to me, haha

The timing Iain's "Tone+Body" suggestion is very interesting because I stumbled across two very similar ideas last night while digging into the BMP tone stack a little more.

The Beavis Audio Research pages (http://beavisaudio.com/techpages/bigmufftonecontrol/) lead me through the original BMP circuit and a couple of variants with the extra "body" control that seemed intriguing (especially since they can mostly be built right on the potentiometers which would save me some space inside the enclosure).

I then ran across a similar sequence of  BMP tone stack "evolution" on the amzfx site (http://www.muzique.com/lab/tone3.htm) which shows how tweaking a few components can shift the frequency response from the typical mid cut of the original BMP circuit with the tone control at noon to a mid boost with the same setting.

I'm starting to think this BMP-based combination of Tone+Body might be where I start first.  My next step then would be to see where I like it best in the Super Fuzz circuit.

i suggest putting them both on a breadboard and just testing out which one sounds best! especially with the values, try and experiment stuff out to get the desired sound.
my personal objection to the BMP tone stack with mid boost is the lack of bass. the bass is attenuated even when the knob is fully to the bass side... you can also employ an active tone control, the superfuzz is fairly complex to begin with, so adding an active tone control isn't a big step forward. if you decide that, i recommend the active James tone stack.

cheers, Iain

[pinkjimiphoton]

hahah, yeah, no california here, but old school new england yankee freak, bro

i agree. lotsa ways to break things.

been around here now for over a decade, lurked for years before that <hell, 20 years or so now> and have seen greatness in newbs and seasoned purveyors both.

but my fav insanity has always been from doing shit wrong, like using a germanium transistor in an opamp feedback loop as a diode... BUT making the transistor active so its not only clipping, but amplifying the signal.... or clipping stuff inside biasing networks. whatever. if it seems wrong, but passes signal, see what it does, exploit the hell out of it.

breadboards are AWESOME. but a pain in the ass sometimes.... contacts wear, connections fail.... but i didn't use mine for years. i'd get a dumb idea, take a hunk of vero, and just have at it.

the point is there are many paths to sonic nirvana. a lot of stuff we think we like, or will like, is smoke n mirrors...
like bass response from guitars... to some guys, that's way more important than to me, hell, i add bass CUTS to my guitars. i gotta bass player and a keyboardist, AND a rhythm guitarist, i would rather find a niche that  cuts. i hate mudd, so i tend to attenuate bass to make tighter sounding circuits. but to other peeps, they WANT that kinda low end roar... i guess my point is, whatever sounds good? is. whatever doesn't sound good? well, it will sound good usually if ya @#$% with it enough, or it may be PERFECT in some guise or circumstance you wouldn't expect.

just do it. let the magick smoke out. burn them fingers. destroy pricey components. there's a price for learning stuff.
i, again, know just enough to be dangerous to myself and others... lol
at this point, i almost see components, passives and semi conductors, like patch cables and effect boxes. i know this particular cap is gonna range this frequency. this voltage divider will get me the gain i need.. this gain range transistor is gonna sound this way, that one, different.
all info gleaned by not being afraid to completely @#$% up.
granted, my area of expertise is fuzz and dirt, and that kinda shit's irrelevant to actual engineering.
but every once in a while, just @#$%ing around will lead ya down a rabbit hole to something cool, that's worth replicating for some other denizens of this here third stone from the sun. or maybe inspire someone to do something COOLER.

just do it. and damn the torpedos!
rock on

[iainpunk]

yeah, i guess your idea of doing it wrong is the same as my idea of applying all the rules. most pedal builders/engineers use most of the rules, but if you take in account the weirdness you can add with the odd and obscure rules, it can be interpreted as 'wrong'. i went to school for electrical engineering, and learning about the weird little quirks of stuff inspired me the most.
my favourite transistor is a BD139 and a BD140 in a sziklai pair, but with the collectors and emitters reversed, this always sounds raunchy, and the curve tracers at school gave quite the odd responses... if biassed right, they can do octave effects. is that wrong to use trannies in 'reverse forward region'? no, its unusual, hell, the moon landing had instruments on board where the transistors needed less gain so the engineers swapped the C and E... but i wouldn't consider it wrong.

fun how we see the same thing differently


cheers, Iain

[debrad]

my personal objection to the BMP tone stack with mid boost is the lack of bass. the bass is attenuated even when the knob is fully to the bass side... you can also employ an active tone control, the superfuzz is fairly complex to begin with, so adding an active tone control isn't a big step forward. if you decide that, i recommend the active James tone stack.

I have to admit that the attenuated bass had me somewhat concerned with that particular version of the BMP tone stack when I first looked at it.  The fact that it caught your attention as well makes me think I should focus more on the "New AMZ" version that flattens the mid cut with the "Body" maxed and the "Tone" at noon and adds a bit back with the "Body" control minimized.

[pinkjimiphoton]

yeah, i guess your idea of doing it wrong is the same as my idea of applying all the rules. most pedal builders/engineers use most of the rules, but if you take in account the weirdness you can add with the odd and obscure rules, it can be interpreted as 'wrong'. i went to school for electrical engineering, and learning about the weird little quirks of stuff inspired me the most.
my favourite transistor is a BD139 and a BD140 in a sziklai pair, but with the collectors and emitters reversed, this always sounds raunchy, and the curve tracers at school gave quite the odd responses... if biassed right, they can do octave effects. is that wrong to use trannies in 'reverse forward region'? no, its unusual, hell, the moon landing had instruments on board where the transistors needed less gain so the engineers swapped the C and E... but i wouldn't consider it wrong.

fun how we see the same thing differently


cheers, Iain

hahah i love using stuff wrong. sometimes reverse beta's transistors just plain fuzz RIGHT.
rock on brother

[debrad]

Hi Everyone,

Just wanted to give you a bit of an update now that I have finally put the Super Fuzz circuit together and added my "tone" and "body" controls based on a modified BMP tone control.  Happily, everything functions as it should and I'm quite happy with the additional controls.

As many of you may have suspected though, I do seem to have a volume loss issue from this that I'm not really happy with.  I definitely get a bump in volume over my clean tone when I turn the effect on but the volume knob has to be well past Noon to make that happen.

I looked at a couple of options to increase the gain of the final transistor section which follows the new tone controls and the volume pot but the first one I tried (reducing the emitter resistor) didn't appear to help.
   
Elsewhere in the forums, I read a post that said adding a "22uf electrolytic bypass cap parallel to the emitter resistor on the last transistor" would increase the output but I haven't tried that (and I'm not 100% sure of what else that mod might do to the circuit).

The other thing I tried...the step that REALLY confirmed how much loss I am getting...was bypassing the new tone controls with a jumper straight to the volume pot.  That created a HUGE volume boost so, even though I think it sounds pretty good WITH the mod, it sounds absolutely massive without it!  Makes me think that if there isn't another option, I might just drop in a SPDT toggle that will switch between stock (no tone controls) and mod (with tone controls).

For the record, I used this BMP-based tone control:


and I stuck it right between the "tone" switch and the "balance" pot in this Super Fuzz circuit:

[PRR]

...this BMP-based tone control:
...right between the "tone" switch and the "balance" pot in this Super Fuzz circuit:

Don't flow tone-network to tone-network. Losses add up. Tone goes to heck.

The Super Fuzz stock has two tone choices, flat or notched. Make it three choices: flat, notched, or BMP. (Wire it temporarily to see if it is worth the expense/hassle of a 3-throw switch, or if one of the other choices is now obsolete.)

[debrad]

I've read a few other posts where people recommended a buffer...either before or after the newly added tone controls.  Would it help me at all to insert a buffer before or after my BMP tone stack?

[iainpunk]

a buffer would lessen the interaction between the preceding stage and the following stage, so, yes, it will work a little bit

the BMP notch is at rougly the same place as the original notch filter and having the body control you can kind of switch between scoop or flat, so i'd say take out the original tone switch filter thing, or leave one of the two in, but modified for instance, one switch side has the BMP for the full and thick fuzz and the other side has the mid scoop, but changed to be around 350Hz for some crunchy/sharp fuzz.


something like this,

cheers, Iain

[Mark Hammer]

1) The W in SWTC is all about the manner in the volume is unaffected by the variable rolloff.  It was a simple little trick for those occasions in which there was no post-tone-control gain-recovery.  Those conditions do not apply in the Superfuzz.

2) The stock midscoop in the Superfuzz can be defeated by inserting variable resistance between the 0.1uf cap and ground.  ZVex did this for the original Octane pedal.  Resistance up to 5k or so yield noticeable and useful degrees of throatiness.  If you want more variability you can adapt that 47k/10k pair used to achieve the no scoop tone and maintain level-balance between the two tone settings.  Make the 47k resistor something like a10k resistor and 0.1uf or .047uf cap.  Then, use a 50k-100k linear pot, with its wiper to ground, one outside lug to the 0.1uf cap in the scoop filter, and the other outside lug to the suggested 10k/0.1uf pair.  Stick a fixed resistor of suitable value (e.g., 10k) in parallel with the leg of the pot between the scoop and ground.  This will provide variations between a sizzling scoop a one end, and a "scoop defeat" with varying degrees of treble cut going in the other direction.  I suppose one could always use two separate pots to achieve this, but I'm partial to the convenience of a single control that does both in reciprocal fashion.

[pinkjimiphoton]

instead of a buffer, which is JUST below unity gain, make it a simple gain stage, gotta breadboard? a buffer will iso the two parts of the circuit, but can't give you any more gain/volume.

you may have to play with a couple values, but really, a, oh, say 10k-50k trimmer from b+ to c, ground e and put your signal to b may get ya enough make up gain to do the trick. you'll need a cap or two for input/output most likely, depending on where ya graft it into the circuit, but then ya can get your volume back, just a set it/forget it kinda way.

lots of ways to skin the cat here. if ya like the tone ya have now, this is probably the easiest/sleaziest way to go.

the SWTC works great, too, with way less loss. i DO like the bmp one cuz ya can hack a quasi midrange into it pretty easily.

i'm not familiar enough with this circuit to speculate enough on it, but you may find ya need more than one stage to keep phase coherence. every stage you go thru is gonna invert the signal, which may or may not be an issue.

props on working it out. fuzz molesting is becoming a dieing art, everyone thinks its all been done, but really, it hasn't. rock on!

[debrad]

Thanks for all the input everyone.  If this was my own Super Fuzz, I'd be content with the 1PDT tone switch of the original but I am kind of stuck going down this road since I'm putting it together for someone else who is keen on something closer to the features/functions of the Danelectro Eisenhower Fuzz (ie. tone switch AND something similar to "bass + treble").

By coincidence, pinkjimiphoton's message came in just as I was reading a few other recommendations here in the forums to stick an LPB-1 boost circuit after the tone control as a relatively simple and effective option for make-up gain (I even have the vero layout with an onboard trimmer that I could use to just "set and forget" inside the enclosure.

What I wasn't aware of, however, is the "phase coherence" issue that he brought up.  Is this phase issue something I still need to worry about if I just tack an LPB-1 onto the end of my new tone stack?

[aron]

Any time I see a fuzz, it makes me think Big Muff tone control. I still like it after all these years. But play around with the tone stack simulator and some of the other filter types can get an enormous variety of tones.

[pinkjimiphoton]

Thanks for all the input everyone.  If this was my own Super Fuzz, I'd be content with the 1PDT tone switch of the original but I am kind of stuck going down this road since I'm putting it together for someone else who is keen on something closer to the features/functions of the Danelectro Eisenhower Fuzz (ie. tone switch AND something similar to "bass + treble").

By coincidence, pinkjimiphoton's message came in just as I was reading a few other recommendations here in the forums to stick an LPB-1 boost circuit after the tone control as a relatively simple and effective option for make-up gain (I even have the vero layout with an onboard trimmer that I could use to just "set and forget" inside the enclosure.

What I wasn't aware of, however, is the "phase coherence" issue that he brought up.  Is this phase issue something I still need to worry about if I just tack an LPB-1 onto the end of my new tone stack?

if its at the END of the circuit, no worries. if its IN the circuit, then it could be an issue. like i said, not all that familiar with this one. sorry for any confusion bro

i think i was thinking of like, the fox tone machine for some reason. brain death strikes. too much blood in my THC systems... i'll lay out with that

merry christmas if ya celebrate that stuff. peace!