fuck overdrive smallsound/bigsound (no schematic but a sort of roadmap to get there)..

[tabbycat]

i know this breaks the golden gfx rule of 'no schematic no vero' so if anyone wants to delete this request on those grounds all i can say is that i'm an anarchist and ignoring reasonable requests is in my job description.

anyway, i have been poorly bad (as they say up north) having a near death experience for the last few months, so have been off the stomp circuit bigtime. but have listened to a ton of youtube pedal demos while laid low and this is one that really blew me away. probably the most inspiring sounding analog pedal i've heard this year (it's been out a while but it's new to me).

alas there is no schematic as such, done and dusted and ready to roll. but there is a two page thread at fsb which ends with this cryptic (to me anyway) outline or circuit roadmap describing how to get from a fairfield barbershop to the fuck (or a version thereof).

so here it is:

schematic for barbershop @ fsb http://freestompboxes.org/download/file.php?id=3285

thread for barbershop @ fsb http://freestompboxes.org/viewtopic.php?f=7&t=4435&start=40

barbershop thread here http://tagboardeffects.blogspot.co.uk/2012/06/fairfield-circuitry-barbershop.html

fuck overdrive thread @ fsb http://www.freestompboxes.org/viewtopic.php?f=7&t=21845&p=254905&hilit=fuck+overdrive+smallsound#p254905

roadmap of sorts by lm3939 @fsb (bottom of page 2 of fuck overdrive thread):

"I've reasoned out how I would recreate the F, but I haven't had time to follow through. Hopefully my thoughts will help:

Start with the straightforward circuit: input J201 gain stage -> 2N5457 gain stage -> second J201 gain stage -> 2N5089 emitter follower. Use the already-traced sorta-similar Fairfield Barbershop as a starting point, and the BOM/PCB screen in this thread to reason out component values. Set up the gain, hicut, and volume pots and make sure this circuit works as you'd expect.

After that, use a pot or two to deliberately misbias the 2N5457 until you get the desired heavy crackling/light cutout effect (toggle), note the bias voltages, then reproduce these voltages by using the envelope follower circuit of the Dr. Quack to screw with the 2N5457's biasing. This'll require some experimentation; maybe have the envelope BJT open/close a path to a parallel biasing resistor.

The momentary footswitch and associated on/off toggle either completes or kills the input to the envelope follower."

i doubt that's enough information for anyone here to be able to make anything of as is, but it may start interested minds spinning and lay the foundations for what might become the fuck overdrive thread here. small acorns...

guitar and bass demos here:




https://www.youtube.com/watch?v=OW-pegj1yMY

[Travis]

I have a fuck overdrive that I bought ASAP when it was first released. It is probably my favorite overdrive, but I haven't used it in a while because the footswitch broke after a couple years of somewhat heavy use

I don't really want to contribute to the dissection of it though, because Brian has been super cool to me, even giving me a PCB to build the mini fuck so I didn't have to buy one when it came out. If you hit up Brian himself you may get the schematic, or maybe a PCB to build one yourself. Or just buy the pedal from him if possible

He's one of the guys making cool new ideas and I don't want to hurt his business.

By the way he plays in Cymbals Eat Guitars if you like them

Here's an old photo of my pedal probly from the day I got it :P

[Travis]

More importantly, you've been missed here. Good to see you back!

Hope things are getting better for you

[ξεναγος νεκροπολης]

+1 buddy. we've missed you.
hope you're ok.

[KT]

What a coincidence !!
I'm also really obsessed with this effect for the moment and I'm experimenting with jfets to try to replicate that effect (see my post in open chat a minute ago :))

I started first by just cascading tilman preamps.

It's fun that there is no schematic available so we can experiment based on the clues that have been posted on freestomp.

[rocket88]

shit bro, i wondered what happened to you tabby. after reading what happened i'm glad you are/getting better. the effect is interesting and from the demo some of the bass settings are absolutely fantastic. you've got in interesting concept, and will have to do some investigating to see what i can contribute to the project.

[Travis]

This thing rocks on bass Zach. Last time I recorded I used the Ric bass > fuck OD > DI

Sounds nice and growly and the exploding amp switch is fun with bass

The mini has slightly more low end. Since Brian added the low cut control on the mini he gave it a little more low end to play with at max

[tabbycat]

hey travis, savvas, zach and all, i hope all is grand with you too.

apologies for the absence and i have missed the site. it's a nice scene here. always interesting things going on and a strong sense of camaraderie. good people here. many thanks for the welcome back.

not much to say about being ill. tiring and boring. i feel like i've been pushed down a thousand flights of stairs and don't have the energy to even get back on the first step. but where there's life there's hope, so just got to dig in and focus on keeping spirits up. concentration is shot (has been going for a while) so building has been a no. may still be for a while, but the temptation being there is a start, and a start is good after a stop.

will back off pushing for a fuck build-by-numbers layout if brian is a little builder and you think this being decoded would harm his business a lot. i noticed on fsb that the thread cooled noticeably after brian dropped by to offer some hints, which (pausing to reflect) may explain why no one has posted a schematic there yet.
obviously these things are inevitable, but i also appreciate there is a certain (positive) community protectiveness around insiders who, whilst not wishing to see their schematics available too soon, do their best to give the community the strongest hints about how such a result may be arrived at through a little guided experimentation. call it 'meeting the tracing beast halfway'. which i respect. reading back through the thread after i read your comments (@travis), i get the feeling is the way others see this one too.

when i'm a bit more together (to be honest i'm barely up to doing this one now anyway, ambition exceeding energy) i'll build the barbershop and start tweaking around on the breadboard to see how close i can get. you never know, i might actually learn something. always a first time.
but that crackling spluttering smashed in amp sound is very seductive and must-have for me (i would say i need it in my arsenal, but google translate might not represent me fairly if non-native english speakers were to copy and paste that).

as for reference material, the barbershop seems to be accepted as a good base, and brian's info and the lm3939 quote fill in a few more gaps. is there anything in particular that i should be thinking about re the crackle? is that only sag or is it the way the caps and sag work together. i've heard sag in some other things, zvex, devi, even a superfuzz, and it doesn't have the same dying bloom of the fuck. more like not enough charge to keep the transistors sparking. the fuck feels more like that dying is pushed maybe by a series of caps slowly unloading charge to keep everything just above choking off to incoherent static. interesting and something i need to understand better.

am getting to that building saturation point where i have one or two decent builds i'm happy with for every major area, fuzz, reverb, modulation, so things have to be 'stand out' for me to want to build now. especially as building has become a struggle. but this one really stands out so find myself obliged, as a compulsive tone-seeker, to re-engage with the science.

it's a great pedal and certainly brian's not asking a ransom for it either. $200 when you are earning a reasonable wage is pretty affordable. not boutique extortion. immediately put in appropriate perspective when you consider what less scrupulous tgp darlings demand for similar (and less), or alt-tgp darlings like seppuku offering circuit-bent nux-joyo cheapies for $300+.

will bear in mind you comment about contacting brian, but feel that while i don't have funds to offer him something in return for his time and energy, i should content myself with the contribution he made to the fsb thread in the spirit in which he intended it, which covers quite a lot of the missing ground. am pretty sure that were i not so foggy-headed right now, it would mean more to me than it currently does.

blah blah blah. am talking too much because i can't do. bad habit. best to silence myself.

it's nice to be back.

viva gfx!

[KT]

Hi,
I think everyone agrees that we don't want to post a schematic of this circuit here, but that it is okay to try to make something similar for personal use, but not commercial benefit.

So I made the cascading jfet part (with dual gain control) and it sounds really good, added a tone control after it (this is not necessary for the moment in my opinion). But when I put an emitter follower (2N5089) between last gain stage and the tone control, the effect is not that nice anymore: high gain is fine, although there is gating happening at the end when I sustain notes, or chords. At low gain setting, there is no sound at all. So I omitted the emitter follower for now.

I started breadboarding, what i think is, the envelope part (blowing amp part) but I am not really confident about how to add it to the circuit.

So is there someone with knowledge about emitter followers and more important envelope detectors, and how about to incorporates these in the circuit? I could email a schematic of what I have. Thanks in advance. [e-mail]    

[Frank_NH]

KT wrote

So I made the cascading jfet part (with dual gain control) and it sounds really good, added a tone control after it (this is not necessary for the moment in my opinion). But when I put an emitter follower (2N5089) between last gain stage and the tone control, the effect is not that nice anymore: high gain is fine, although there is gating happening at the end when I sustain notes, or chords. At low gain setting, there is no sound at all. So I omitted the emitter follower for now.

Try using a JFET source follower as shown in Jack Orman's wonderful article about buffers;

http://www.muzique.com/lab/buffers.htm

If the output impedance of your last gain stage is high, a BJT emitter follower may not be a good choice, and may be the reason you're getting the odd behavior.  Let me know if this works.

[KT]

Thanks for the info and links!
I've got the envelope crackle also working but it needs a lot of finetuning to sound right. So I've got to test a lot of things. For example, do I split my input immediately to the overdrive part and envelope part, or do I use the quack buffer after input and split my signal afterwards.. And I'm still doubting if I should invest time in a tone control cause it sounds fine even without.

[tabbycat]

@frank
re "Try using a JFET source follower as shown in Jack Orman's wonderful article about buffers;

http://www.muzique.com/lab/buffers.htm"

thanks very much for the tip frank, all greek to me atm but will read into that in due course and see how that might fit in with the gut shots at fsb and the pcb board from the smallsound blog below.

@kt "do I use the quack buffer after input and split my signal afterwards.. And I'm still doubting if I should invest time in a tone control cause it sounds fine even without."

from p2 of fsb thread:

(lm3939) "use a pot or two to deliberately misbias the 2N5457 until you get the desired heavy crackling/light cutout effect (toggle), note the bias voltages, then reproduce these voltages by using the envelope follower circuit of the Dr. Quack to screw with the 2N5457's biasing"

from p1 of fsb thread:

(jonasx26) "Looks like the yellow LED anode is connected to pin 5 of the TL072. Bet its used for the offset-bias-trick used in many envelope-followers. Dr. Q etc.."

(brian, smallsound) "right you are."

from amz http://www.muzique.com/schem/quack.gif

re the tonestack question, if you know how to use the duncan tone stack calculator this info might be useful (from the smallsound fuck page) to help give you ideas about cap values that might suit.

"highcut: a passive 6db/octave LPF which attenuates frequencies higher than the cutoff, from 1.5kHz to around 16kHz. "

http://www.smallsoundbigsound.com/products/fuck-overdrive/#specs

and as if to both thicken and clarify the plot simultaneously, we have the pcb screenprint (from smallsound blog) which will give you the values of all the parts used, but not how they connect. reminds me of the famous morecombe and wise previn sketch "i'm playing all the right notes, but not necessarily in the right order"

if 'join the dots' (without numbers) is to your taste, feast on this...



i'm far too deep in a semi-permanent solpadol fog to make any more sense of this than that, but if you like mysteries, scoob...

[Travis]

Wow things are really heating up in here! I'd love to hear what you've got so far KT

Looking forward to following along here. Also jamming out to Brian's band right now

http://youtu.be/28FWJGTkcYg

[KT]

Yes, Cymbals eat guitars are great.

I'm very happy with what I got so far. For the moment I'm playing with different values of the quack circuit (10uF too ground --> bigger, parallel resistor) because the decay of "burst mode" is to sudden and cuts out a bit after I hit my guitar strings too hard. On the video's the f* also does this on some settings a bit but not so much as mine.

Using the quack's buffer before my dirt doesn't seem to matter.

It's time to decide some things and put the dirt part on vero cause my breadboard is a mess and it is difficult too tweek the envelope part..

[KT]

So I settled on the overdrive part. I am using a SWTC3 for the moment (don't know if I should include a buffer before the tone control or after, I've been reading on tone controls and buffers but I don't find useful info on both together).
If you look at the quack Q2, if there is a guitar signal coming to it's base, does this result in something flowing from the collector to emitter to ground? This is how I was thinking, so I thought I could only bias the jfets by putting a parallel resistor at the source bias resistor. But if I connect the quack circuit to the drain of a jfet, the resulting sound of the effect is the same.
The thing I put together now really has some nice sounds already and similarity to the F* sound, but especially the cutting out and starved sounds. The F* more "crackles" then "starves" on a lot of youtube sound samples, I don't know how to get to this.

(what is the easiest way to put sound samples from my cellphone here? I've never put sound samples online before)
 

[notnews]

KT, awesome work. I can't wait to hear what your circuit sounds like.

Re: samples from your cellphone there are a few pretty simple ways to do this.. you could upload them straight to your dropbox, then provide a link to that file in your dropbox here. You could also send the file to your email address, then upload the file itself here? I use dropbox all the time for a bunch of purposes, I would tend to think that would be easiest on you and the site itself.

[tabbycat]

KT wrote

So I settled on the overdrive part. I am using a SWTC3 for the moment (don't know if I should include a buffer before the tone control or after, I've been reading on tone controls and buffers but I don't find useful info on both together).
If you look at the quack Q2, if there is a guitar signal coming to it's base, does this result in something flowing from the collector to emitter to ground? This is how I was thinking, so I thought I could only bias the jfets by putting a parallel resistor at the source bias resistor. But if I connect the quack circuit to the drain of a jfet, the resulting sound of the effect is the same.
The thing I put together now really has some nice sounds already and similarity to the F* sound, but especially the cutting out and starved sounds. The F* more "crackles" then "starves" on a lot of youtube sound samples, I don't know how to get to this.

(what is the easiest way to put sound samples from my cellphone here? I've never put sound samples online before)

sounds like you are really digging in kt. i admire and envy your energy and persistence.
re the drain on the jfet, might be worth trying a fat cap to slow down drain to give a less immediately starved sound? bleeding to death rather than choking?
i was watching some clips by the great jimi photon recently re his experiments with the harmonic percolator/photonic jeurgulator, and the insightful comments he made about the caps on the drain made me think something like that might be applicable to the fuck crackle, or effecting a workalike.
for me that crackle is the great bit. there are other things (barbershop) that can do good thick overdrive, but that crackle is what i'm focused on. maybe the crackle on another drive might not work, but only isolating it from the fuck will tell.

i have heard a lot of starved pedals, fuzz factory to superfuzz, and it is not the same as the smoulder and decay of the crackle, so i think a big cap is involved in slowly bleeding out that decay.

anyway, wisdom from the legend that is jimi photon, live from mount olympus...

comments re caps and drain a 1m30-3m30 and all over, but mostly there.



and more on the hp/pj here... (percolation on full whack from 9m30s on).



may be relevant, may not, seemed so to me.

btw there is another quacky schematic by rog with orman/hammer nods, might resolve issues you are having with dr q extracts?

http://home-wrecker.com/nurse-quacky.png

[tabbycat]

was looking at this last night and am trying make sense of this extract from something i quoted from the fsb thread above...

from p2 of fsb thread:

(lm3939) "use a pot or two to deliberately misbias the 2N5457 until you get the desired heavy crackling/light cutout effect (toggle), note the bias voltages, then reproduce these voltages by using the envelope follower circuit of the Dr. Quack to screw with the 2N5457's biasing"

from p1 of fsb thread:

(jonasx26) "Looks like the yellow LED anode is connected to pin 5 of the TL072. Bet its used for the offset-bias-trick used in many envelope-followers. Dr. Q etc.."

(brian, smallsound) "right you are."

http://www.freestompboxes.org/viewtopic.php?f=7&t=21845&hilit=fuck+overdrive+smallsound&sid=157183df1c3279a3cf39329656bc15ba

my (albeit slight) understanding of these suggestions is... that what is being proposed is that the part of the quacky that sits between q1 and q2 in the schematic (lower half, which contains the sensitivity and range controls) will be inserted between q1 and q2 of whatever the circuit for the rest of the fuck overdrive proves to be, but could possibly be substituted/shoe-horned into the same position (between source of q1 and gate of q2) in a related circuit (such as the barbershop) with similar results (with compensatory tweaking).

is that what is going on with the quacky bit?

http://www.muzique.com/schem/quack.gif
or
http://home-wrecker.com/nurse-quacky.png

[KT]

I use the entire part from q1, envelope follower, q2. By altering q2 source bias I get results similar to the sound from the "light position" (toggle), the cutting out sounds. The crackling I can't reproduce yet. I'll try to make a schematic of what I have now this week. Should I send it to you by email tabby?

[tabbycat]

KT wrote

I use the entire part from q1, envelope follower, q2. By altering q2 source bias I get results similar to the sound from the "light position" (toggle), the cutting out sounds. The crackling I can't reproduce yet. I'll try to make a schematic of what I have now this week. Should I send it to you by email tabby?

is this on the barbershop? i actually made this post at fsb this afternoon in the fuck thread (bottom of page 2) re how i thought it would apply to that one. i have only just got a basic grasp of what an envelope follower actually  is, so i'm a bit behind you and probably most who understand anything about them.
but i presented what sketchy little ideas i had as a 'this is the plan, am i pointing in the right direction?' kind of format to see what people thought.
http://www.freestompboxes.org/viewtopic.php?f=7&t=21845&start=20

it's the 'crackle/smashed amp' sounds i'm most after. like a clipping stage, tone stack, etc, it's something i want to isolate then apply to a variety of overdrives, even distortions and fuzzes, to see what it does. seems like an interesting thing to do. but removing the organ from a donor and transplanting it into the new patient with non-fatal results is a fine art.

re a schem, i'd like to see it. depending on how public you want to go, maybe post it here, and/or at fsb, either in the fuck thread or in the diy designs thread http://www.freestompboxes.org/viewforum.php?f=28 sometimes mods move things from tracing threads if they are not mostly related to the circuit in hand, so that might be the place for it.
we've got some beautiful minds here. and the guys at fsb are the kind of hardcore tech boffins who reverse-engineer space shuttles for amusement like taxi drivers do soduko. between the two forums there is bound to be some useful feedback. and then there is me...

wherever you feel happiest posting. i'm not sure what can be done through the messaging thing here otherwise i can send you my email addy.

but glad to hear you are still amused by it and not fed up with it.