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DIY Stompboxes => Building your own stompbox => Topic started by: mattpocket on March 23, 2007, 04:27:39 AM

Title: Weird pedals
Post by: mattpocket on March 23, 2007, 04:27:39 AM
Hi,

A friend of mine has asked me to build him a weird and wonderful pedal. Something that completely destroys the sound of anything that passes throgh it. Maybe with body contacts (for pitching/volume), optical thermins, theremin controls. Or just something really strange. To give you an idea what he likes he already has something similar to the Pungent Bzzz and he creams over Zvex's Fuzz Probe all the time! haha

Any suggestions for what I could make him?

Matt
Title: Re: Weird pedals
Post by: krachbox on March 23, 2007, 04:44:57 AM
hi matt,

buy one of these voice changer toys, adapt it for guitar, put a pot in place of the resistor that sets the sampling frequency and you have a really weird effect with lots of options:

something like these:

http://www.electronickits.com/kit/complete/surv/ck211.htm

http://www.velleman.be/fr/en/product/view/?id=362322

I made one from this:

http://www.grandrivertoys.com/Pages/products/Voice_Changer.htm

Janis
Title: Re: Weird pedals
Post by: black mariah on March 23, 2007, 04:57:10 AM
4mspedals.com :icon_wink:
Title: Re: Weird pedals
Post by: mattpocket on March 23, 2007, 05:51:18 AM
The voice changer idea sounds cool...

Keep em coming!
Title: Re: Weird pedals
Post by: axg20202 on March 23, 2007, 06:07:41 AM
...there's lots of info on t'internet about bent sounds/circuit bending. You'd be amazed how angry and evil a Speak-and-Spell can get with a bit of surgery. :-)....bending existing noise boxes is definitely a good suggestion for weird, unique effects....


Andy.
Title: Re: Weird pedals
Post by: jonathan perez on March 23, 2007, 06:11:56 AM
ATARI PUNK CONSOLE
Title: Re: Weird pedals
Post by: black mariah on March 23, 2007, 06:22:50 AM
Quote from: thebattleofmidway on March 23, 2007, 06:11:56 AM
ATARI PUNK CONSOLE

Reminds me I need to build one of those...
Title: Re: Weird pedals
Post by: mattpocket on March 23, 2007, 07:21:40 AM
Yeah I suggested bending to him, and noise makers. He already has a speak and spell. He is looking for something for guitar now. A tough customer.
Title: Re: Weird pedals
Post by: axg20202 on March 23, 2007, 08:03:01 AM
...I guess you need to find a noise box that has a means to process incoming audio then, rather than just a noise maker. Shame. I have a friend who's got a Speak and Math that sounds like it's a means of communicating with the devil - albiet a devil that's really into addition....my mate does an amusing 'number of the beast' joke cover version with it... :)
Title: Re: Weird pedals
Post by: choklitlove on March 23, 2007, 08:08:02 AM
Parallel Universe (http://experimentalistsanonymous.com/diy/)
UglyFace (http://www.home-wrecker.com/uglyface.html)
PWM (http://geocities.com/worthekik/pulsewave.html)
Thing Modulator (http://geocities.com/worthekik/thing.html)
Noise567 (http://personal.inet.fi/koti/holmberg/images/noise567.jpg) (circuit written with an LDR)
Hysteresis Oscillator (http://geocities.com/worthekik/hysteresis.html)
Crash Sync (http://www.hollis.co.uk/john/circuits.html)
BugCrusher (http://www.bugbrand.co.uk/pages/electronics.htm)

any of these (and any pedal, for that matter) can use LDRs in place of any pot.  as for body contacts, get your circuit bending face on and start touching around!

good luck, and welcome to, in my opinion, the most interesting part of our hobby.  forget boring fuzzes.  noise!
Title: Re: Weird pedals
Post by: choklitlove on March 23, 2007, 08:27:08 AM
oh, yeah.  he might like a feedback looper (http://experimentalistsanonymous.com/diy/Schematics/Buffers%20Switchers%20Mixers%20and%20Routers/Feedback%20loop.gif), as well.
Title: Re: Weird pedals
Post by: axg20202 on March 23, 2007, 08:30:10 AM
body contact stuff.....reminds me of the ludicrous midi-control suit I saw in Sound on Sound a while back.....imagine going on stage with that thing.....spinal tap for the new millennium...
Title: Re: Weird pedals
Post by: caress on March 23, 2007, 11:06:17 AM
Quote from: krachbox on March 23, 2007, 04:44:57 AM
hi matt,

buy one of these voice changer toys, adapt it for guitar, put a pot in place of the resistor that sets the sampling frequency and you have a really weird effect with lots of options:

something like these:

http://www.electronickits.com/kit/complete/surv/ck211.htm

http://www.velleman.be/fr/en/product/view/?id=362322

I made one from this:

http://www.grandrivertoys.com/Pages/products/Voice_Changer.htm

Janis

the velleman kit is the same as the dean hazelwanter pitchshifter at http://www.generalguitargadgets.com, btw.

you could also try building a pedal, maybe fuzz/distortion? and trying some "bends" within the circuit for some fun weird sounds.  i do it all the time...
Title: Re: Weird pedals
Post by: mattpocket on March 23, 2007, 12:05:31 PM
Quote from: choklitlove on March 23, 2007, 08:27:08 AM
oh, yeah.  he might like a feedback looper (http://experimentalistsanonymous.com/diy/Schematics/Buffers%20Switchers%20Mixers%20and%20Routers/Feedback%20loop.gif), as well.

what does the feedback looper do? give me an example of where i'd use it

matt
Title: Re: Weird pedals
Post by: reverberation66 on March 23, 2007, 12:37:19 PM
           Can anyone tell me how to adapt the voice changer or any other noise making toy, etc. to work with a guitar signal?  someone mentioned this in this thread but I wasn't aware that such a thing was possible without a good deal of difficulty...is there a way to do this?
Title: Re: Weird pedals
Post by: axg20202 on March 23, 2007, 01:15:08 PM
er...not sure, but I would guess that, seeing as there's an internal mic in a voice changer, it would involve modifying the existing mic input to a guitar input - not too difficult I guess - you'd maybe need to add a basic preamp circuit. Then you could fiddle with the output end of the cicuit to bypass any internal speaker or whatever and come out to a jack instead. Setting in and out impedences would be required I guess, but others would be in a better position to advise on that than me....

ANdy.
Title: Re: Weird pedals
Post by: krachbox on March 23, 2007, 02:33:47 PM
with the one I modified I just put a fuzz circuit in front of it and it worked. the output uses a 386 opamp anyway, so I just hooked an output jack to it and that's it.
Title: Re: Weird pedals
Post by: The Tone God on March 23, 2007, 02:55:54 PM
Some self promotion here.

Christine (which can self oscillate), Blade (Crossover simulation), Forsaken (which has a touch control feature).

Andrew

Title: Re: Weird pedals
Post by: Ronsonic on March 23, 2007, 03:14:24 PM

Octavia. Sick enuff with a guitar. Pull the plug out of the guitar and just work the controls for more disease.

Ron
Title: Re: Weird pedals
Post by: tcobretti on March 23, 2007, 03:26:00 PM
The Random Number Generator - it a weird random arpeggiator fuzz for guitar.  I didn't design it, but there's a schem and vero layout in my gallery.

Also, I think there's a v2 floating around with more controls.
Title: Re: Weird pedals
Post by: arma61 on March 23, 2007, 04:41:37 PM
Hi, about the feedback looper cannot figure how to plug in the guitar, could somebody explain me the whole connections

Thx vm
Title: Re: Weird pedals
Post by: Hambo on March 23, 2007, 05:28:53 PM
^^You need a cable. ahahaha   :icon_mrgreen:

Yeh, my suggestion is with Tcobretti there.. the Random number generator, its about my favouritist pedal ever, I just love the pandemonium, you can turn it from barely recognisable smoosh on chords to almost tunefulness with carefully mute-separated single notes (if that makes any sense). Put a distortion box in front of it and squeeze out a 3-4th fret harmonic it just goes BERSERK! excellent.

And also the uglyface. Much fun.

TBH I dont find the feedback loop much use except for with a delay, you can get some good noises with.
Title: Re: Weird pedals
Post by: ambulancevoice on March 23, 2007, 05:44:03 PM
yeah
random number genorator @#$%s up anything put through it
diffinetly try it
there is a vero board layout in the gallery somewere
just search for it
Title: Re: Weird pedals
Post by: calculating_infinity on March 23, 2007, 06:06:25 PM
Most circuits listed are previously stated in other posts asking for "weird" "noisey" "crazy pedals".  I've built the PU v1 and it sounds good.  Try reading EXPANons site as weird noisey cool stuff seems to be his forte.  You may learn something along the way as well.
Title: Re: Weird pedals
Post by: syndromet on March 23, 2007, 06:35:36 PM
Try some of tim escobedos stuff. I have a psychtar and a thing mod boxed up together. Sounds really wacky. Check the sonic destroyer over at syndromet.com for more info.
Title: Re: Weird pedals
Post by: doug deeper on March 23, 2007, 08:50:36 PM
that random number generator schematic has a bunch of errors.
Title: Re: Weird pedals
Post by: doug deeper on March 23, 2007, 08:54:54 PM
try this!
(http://i10.photobucket.com/albums/a113/midfielectronics/rng.jpg)
Title: Re: Weird pedals
Post by: oldrocker on March 23, 2007, 09:31:50 PM
A Nyquist Aliaser either transistor or CMOS versions.  I added the oscillator to mine and I get some weird effects from it.  I built the one from JC maillets website.
http://moosapotamus.net/IDEAS/nyquist/NyquistENV2.gif
http://www.logmonster.com/images/full/?pic=Nyquist2_1170089100-422-14678.jpg
http://www.logmonster.com/images/full/?pic=aliaser5_1169957698-422-14674.jpg
Title: Re: Weird pedals
Post by: Hambo on March 23, 2007, 09:46:48 PM
Mr Deeper.

Thats the one I used, and I would like to say a big thanks!
I Love that noise
;D
Title: Re: Weird pedals
Post by: sfx1999 on March 23, 2007, 11:10:57 PM
Skyripper fuzz
MXR Blue Box
Title: Re: Weird pedals
Post by: tcobretti on March 24, 2007, 12:22:59 AM
Thanks for the schem Doug!  I plan to pull the bad and replace it with the good one, but please pm me if you want it down altogether.
Title: Re: Weird pedals
Post by: calculating_infinity on March 24, 2007, 12:37:39 AM
Yeah thanks for sure Doug!  If only I had the transistors to breadboard/perf it!  All this talk about it really sparked my interest in it.  Dont forget about RG's CMOS psuedorandom generator http://geofex.com/FX_images/pseudorandom2.pdf .  I haven't built it but coming from RG it should be good.
Title: Re: Weird pedals
Post by: tcobretti on March 24, 2007, 01:57:39 AM
8bit, I'm pretty sure the RNG will work with any low hfe transistors.  I remember plugging many into mine and it not making that much of a difference.
Title: Re: Weird pedals
Post by: doug deeper on March 24, 2007, 02:27:05 AM
yeah most will work fine, this combo was a blind taste test of sorts, and i just stuck with it.
feel free to post the new schematic in the gallery, i dont sell to many of these now adays (it was my first design, that i never really intended on selling) so i might as well share!
also,has anyone noticed the little delayed squeek that happens when you stop playing?
i think its pretty funny, and no one has ever mentioned it to me!
Title: Re: Weird pedals
Post by: krachbox on March 24, 2007, 03:37:22 AM
yeah, I also built the generator, it's a lot of fun to mess around with (socket the transistors and maybe other components and experiment). it also works nicely in a feedback loop creating some octave down also and was quite touch sensitive depending on the other effects.

@doug: what does the 100k pot in the early version of the RNG do?
Title: Re: Weird pedals
Post by: calculating_infinity on March 24, 2007, 05:24:13 PM
Quote from: tcobretti on March 24, 2007, 01:57:39 AM
8bit, I'm pretty sure the RNG will work with any low hfe transistors.  I remember plugging many into mine and it not making that much of a difference.
Quote from: doug deeper on March 24, 2007, 02:27:05 AM
yeah most will work fine, this combo was a blind taste test of sorts, and i just stuck with it.
feel free to post the new schematic in the gallery, i dont sell to many of these now adays (it was my first design, that i never really intended on selling) so i might as well share!
also,has anyone noticed the little delayed squeek that happens when you stop playing?
i think its pretty funny, and no one has ever mentioned it to me!


Thanks a lot guys, I'm going to have to try building one this weekend.  Thanks for sharing Doug! 
Title: Re: Weird pedals
Post by: ambulancevoice on March 24, 2007, 05:51:11 PM
http://aronnelson.com/gallery/album161/Random_Number_Vero

theres a vero for the rng, done using the schem from above
Title: Re: Weird pedals
Post by: sfx1999 on March 24, 2007, 07:42:21 PM
Have you considered the Blue Box? It's a fuzz and two octave down box that has a knob to mix with your signal. There is a sound clip on Dunlop's site -> http://www.jimdunlop.com/index.php?page=products/pip&id=245&pmh=products/picks.
Title: Re: Weird pedals
Post by: doug deeper on March 24, 2007, 09:15:09 PM
Quote from: krachbox on March 24, 2007, 03:37:22 AM
yeah, I also built the generator, it's a lot of fun to mess around with (socket the transistors and maybe other components and experiment). it also works nicely in a feedback loop creating some octave down also and was quite touch sensitive depending on the other effects.

@doug: what does the 100k pot in the early version of the RNG do?

the pot just changes the quality of the fuzz, from standard rng to really lo-fi.
Title: Re: Weird pedals
Post by: oldschoolanalog on March 24, 2007, 10:12:37 PM
UGLY FACE!  ;D
Title: Re: Weird pedals
Post by: ambulancevoice on March 25, 2007, 03:42:44 AM
oh, doug, does it matter if the 100k pot is a specific taper?
Title: Re: Weird pedals
Post by: doug deeper on March 25, 2007, 01:49:17 PM
nope!
i use linear taper for both.
Title: Re: Weird pedals
Post by: mattpocket on March 26, 2007, 06:13:10 AM
Thanks for all the help guys. I am spoilt for choice.

I really dont know what to build now.

So really, asking you knowledgable lot made things worse haha

Matt
Title: Re: Weird pedals
Post by: ambulancevoice on March 27, 2007, 06:52:43 AM
Quote from: doug deeper on March 25, 2007, 01:49:17 PM
nope!
i use linear taper for both.


both? where is the second pot?
Title: Re: Weird pedals
Post by: doug deeper on March 27, 2007, 01:16:39 PM
the 100k resistor around the last two stages used to be a pot.
its the other control mentioned a few posts back, the incorrect schematic will show you were it goes if you choose to use it.
Title: Re: Weird pedals
Post by: calculating_infinity on March 27, 2007, 02:26:54 PM
Quote from: doug deeper on March 27, 2007, 01:16:39 PM
the 100k resistor around the last two stages used to be a pot.
its the other control mentioned a few posts back, the incorrect schematic will show you were it goes if you choose to use it.


Hrmm, I cant find the incorrect schem to add this 2nd pot.  Would it be the 100k resistor that comes from the collector of the last 3904?  Or is it the one coming from the collector of the pn2222?  I'm sure both guesses are wrong!  If I did wire this pot, lug 1 would go to where one resistor was and where does the wiper and the other lug go?  Ah to be a noob.  Thanks.

-Jonathan
Title: Re: Weird pedals
Post by: calculating_infinity on March 27, 2007, 09:56:44 PM
Ok I took the time to read how to wire the pot up right  :icon_redface: .  So you can ignore that question.  Still trying to figure out which 100k to sub out (at work).  I read an old post saying it was "the bottom one".  I am going to assume that it is the 100k in the bottom of the schem that comes from collector of the pn2222, which goes to the .01 output cap.  I'm still kind of a newb but really I'm trying to learn  :icon_razz: . 


Thanks,
-Jonathan
Title: Re: Weird pedals
Post by: doug deeper on March 27, 2007, 11:08:09 PM
yep thats the one!
so just wire up the pot as a variable resistor and put it in the place of the fixed resistor.
i wouldnt worry about not getting this circuit and being a "NOOB"  :)
the circuit doesnt really make much sence to begin with, i didnt really have to much design knowledge when i came up with it, and it was a whole lot of sticking stuff in randomly till i got something cool.
but it does sound pretty insane and unique.

Title: Re: Weird pedals
Post by: ambulancevoice on March 28, 2007, 03:41:25 AM
Quote from: doug deeper on March 27, 2007, 11:08:09 PM
yep thats the one!
so just wire up the pot as a variable resistor and put it in the place of the fixed resistor.
i wouldnt worry about not getting this circuit and being a "NOOB"  :)
the circuit doesnt really make much sence to begin with, i didnt really have to much design knowledge when i came up with it, and it was a whole lot of sticking stuff in randomly till i got something cool.
but it does sound pretty insane and unique.



same, as soon as i saw the schematic, i immediately thought that it had it done at random for sake of experimenting
after i build i my buzz box, im gonna do this
what did the second pot do exactly?
Title: Re: Weird pedals
Post by: smnm on March 28, 2007, 07:58:06 AM
Quote from: doug deeper on March 27, 2007, 11:08:09 PM
yep thats the one!
so just wire up the pot as a variable resistor and put it in the place of the fixed resistor.

I found that this pot didn't made much difference to the sound on mine. Since I had the space on the side of the box, I removed it and put in pots in place of the collector resistors on the first 3 transistors. Lots of different sounds now - and the overall output is so huge you can cut the voltages right down and it still makes a huge noise. Reducing power to 1st resistor cuts some of the ear-blistering highs, but maintains the roar. Liking it!
I've tried lots of diff transistors in mine and they change the sound a LOT, especially 1 & 2. Worth messing with.
Title: Re: Weird pedals
Post by: doug deeper on March 28, 2007, 02:02:28 PM
on a side note, the first two stages make a pretty neat buzzy fuzzzz on there own.
Title: Re: Weird pedals
Post by: Giglawyer on March 28, 2007, 02:52:52 PM
Sorry if someone already suggested this...

http://www.moosapotamus.net/THINGS/funnycat.htm

The Funny Cat pedal seems like a weird build to me.
Title: Re: Weird pedals
Post by: mattpocket on March 29, 2007, 03:51:59 AM
Quote from: tcobretti on March 24, 2007, 01:57:39 AM
8bit, I'm pretty sure the RNG will work with any low hfe transistors.  I remember plugging many into mine and it not making that much of a difference.

I dont suppose the poster of this could post the layout in here as an image, since the layouts gallery is down?

Matt
Title: Re: Weird pedals
Post by: smnm on March 29, 2007, 04:16:52 AM
Quote from: mattpocket on March 29, 2007, 03:51:59 AM

I dont suppose the poster of this could post the layout in here as an image, since the layouts gallery is down?

I don't think this one's in the layouts gallery - I did a perf layout, just by following Doug's schematic almost exactly. I'm not sure if I drew it up very neatly, but I could scan it for you tonight if you like.

Simon
Title: Re: Weird pedals
Post by: mattpocket on March 29, 2007, 06:47:41 AM
Someone posted a link to one... if you go back in the topic, I think its on the second page...

Thanks for the offer though, but I am guessing the dude who posted the link will have it on his computer and could post it up here...

Ta!
Title: Re: Weird pedals
Post by: tcobretti on March 29, 2007, 07:43:09 PM
I made that layout, and strangely I don't have a copy of it.  It's pretty simple, it might be a good time to learn how to make a vero layout.  I'll happily check it for you if you post it here.

BTW, this has nothing to do with the recent unpleasantness.  I honestly don't have a copy.
Title: Re: Weird pedals
Post by: mattpocket on March 30, 2007, 04:08:19 AM
I am building a random number generator too...

What tranny could I use instead of the PN2222 as I cant find this on smallbear... and please dont just say any low hfe tranny, cos I havent got the foggiest idea what that means! haha if you would care to explain what it means go ahead, and how I would go about finding transistor substitutions in the future...

Thanks

Matt
Title: Re: Weird pedals
Post by: choklitlove on March 30, 2007, 04:28:03 AM
this is great for transistor subs:
http://aronnelson.com/gallery/The-Mod-Zone-%21/TRANSISTOR_SUBSTITUTION_CHART?full=1 (http://aronnelson.com/gallery/The-Mod-Zone-%21/TRANSISTOR_SUBSTITUTION_CHART?full=1)

i think the 2N2222 would be the same.  good luck.
Title: Re: Weird pedals
Post by: tcobretti on March 30, 2007, 11:28:24 AM
For the purposes of this circuit, I think 2N3904 or 2N4401 would work fine.
Title: Re: Weird pedals
Post by: doug deeper on March 30, 2007, 03:53:49 PM
id give the 2n4401 a whirl as a sub for the pn2222, a 2n2222a should work as well...
something a little on the noisey unstable side is best.
Title: Re: Weird pedals
Post by: ambulancevoice on March 31, 2007, 03:42:59 AM
for any chance doug, do you still have the old red poorly drawn version of the rng?
i would just like to see how the 2nd pot is wired
Title: Re: Weird pedals
Post by: calculating_infinity on March 31, 2007, 04:32:42 AM
Quote from: 8bitRockOut on March 27, 2007, 09:56:44 PM
Ok I took the time to read how to wire the pot up right  :icon_redface: .  So you can ignore that question.  Still trying to figure out which 100k to sub out (at work).  I read an old post saying it was "the bottom one".  I am going to assume that it is the 100k in the bottom of the schem that comes from collector of the pn2222, which goes to the .01 output cap.  I'm still kind of a newb but really I'm trying to learn  :icon_razz: . 


Thanks,
-Jonathan
Quote from: doug deeper on March 27, 2007, 11:08:09 PM
yep thats the one!
so just wire up the pot as a variable resistor and put it in the place of the fixed resistor.
i wouldnt worry about not getting this circuit and being a "NOOB"  :)
the circuit doesnt really make much sence to begin with, i didnt really have to much design knowledge when i came up with it, and it was a whole lot of sticking stuff in randomly till i got something cool.
but it does sound pretty insane and unique.



I wired it up with both pots and I like the extra pot, it really makes a difference in my build.  At one end its really trebly high pitch with some glitchy lower octaves randomly.  At the other is almost a constant lower octave and less random glitchyness still fun!  I'm just waiting for some enclosures to get in the mail and finish the build.  I actually made one then desoldered when I found out about the 2nd pot.  I couldn't get it to work so I set it aside and made another one.  I ended up getting the other one fixed so now I have two!   :icon_eek:  I use all 2N9304s and there is constant noise.  I think I need to get lower hfe trannies like doug suggested in an earlier post.  IIRC the 2N3904's I put in had hfe's ranging from 220-320 which I assume is pretty high.   Anyways have good luck and have fun! 

-Jonathan
Title: Re: Weird pedals
Post by: Hambo on March 31, 2007, 08:21:28 AM
It is really excellent to see people pushing this design around a bit. I always liked the sound but find it a bit hard to use other than in controlled bursts, so I'm really interested to see what happens here :). I did build a second myself with sockets for all the transistors, but I found it made little difference what was in there.. then when I put the specified trannies in, technically it should sound the same.. but no, its totally different to the first one I built, in a not very excellent sort of way... I gave up a bit then to mess about with some other stuff (Uglyface :))

Might have to dig this out again if I can get some time.
Title: Re: Weird pedals
Post by: ambulancevoice on March 31, 2007, 09:08:15 AM
Quote from: smnm on March 28, 2007, 07:58:06 AM
Quote from: doug deeper on March 27, 2007, 11:08:09 PM
yep thats the one!
so just wire up the pot as a variable resistor and put it in the place of the fixed resistor.

I found that this pot didn't made much difference to the sound on mine. Since I had the space on the side of the box, I removed it and put in pots in place of the collector resistors on the first 3 transistors. Lots of different sounds now - and the overall output is so huge you can cut the voltages right down and it still makes a huge noise. Reducing power to 1st resistor cuts some of the ear-blistering highs, but maintains the roar. Liking it!
I've tried lots of diff transistors in mine and they change the sound a LOT, especially 1 & 2. Worth messing with.

which collector resistors?
the ones coming from the base to collector
or the ones going off the collector
(not the power supply ones btw)
Title: Re: Weird pedals
Post by: doug deeper on March 31, 2007, 01:40:56 PM
ok here is an updated schematicwith the second pot.
(http://i10.photobucket.com/albums/a113/midfielectronics/rngorig.jpg)
Title: Re: Weird pedals
Post by: doug deeper on March 31, 2007, 01:41:35 PM
and youcan hear a clip of how it should sound here:
midfielectronics.com
Title: Re: Weird pedals
Post by: smnm on March 31, 2007, 04:28:08 PM
Quote from: ambulancevoice on March 31, 2007, 09:08:15 AMwhich collector resistors?
the ones coming from the base to collector
or the ones going off the collector
(not the power supply ones btw)

... sorry to be so imprecise, I didn't have the schematic in front of me when I posted - I did mean the resistors going from the power supply TO the collectors - having three pots does make any kind of consistent control difficult, but that's hardly the point for this pedal, and it's good for maximum variability - I'm digging the starved transistor sound, reminds me of the horrible/great Swell Maps (uk punk/post-punk/avant band of the 70s) gtr sounds.
Pots on the base to collector resistors you mention would also alter the interaction of the 3 also, though (I don't know how, but you could try it....)
Title: Re: Weird pedals
Post by: ambulancevoice on March 31, 2007, 07:59:06 PM
so you replaced the fixed power to collector resistors with pots right? and that yielded interesting results?
sorry, id like as many pots of possible to get as many sounds as possible
since with the "music" i do involving alot of knob twiddling
Title: Re: Weird pedals
Post by: caress on March 31, 2007, 09:17:58 PM
i think what smnm meant was to add a voltage starve pot...if you want to add more knobs you can always add a switch and pot wired between the in/out for feedback control.  also try adding diodes in feedback loops in various parts of the circuit, maybe a cap to ground at the end, send the collector of one transistor to the base of an earlier one, etc etc...
Title: Re: Weird pedals
Post by: ryanscissorhands on April 01, 2007, 10:24:28 AM
My suggestion would be an Uglyface with an optional footpedal to control the frequency. That would certainly give you a sick-sounding, controllable nasty fuzz-like sound.
Title: Re: Weird pedals
Post by: mattpocket on April 02, 2007, 03:59:47 AM
Seems like some interesting ideas floating around here.

Quote from: caress on March 31, 2007, 09:17:58 PM
if you want to add more knobs you can always add a switch and pot wired between the in/out for feedback control.
what is feedback control? and what would this pot do for the sound. where would I connect it?

Quote from: caress on March 31, 2007, 09:17:58 PM
also try adding diodes in feedback loops in various parts of the circuit,
what does this involve a simple diode in line, where would I hook each end of the diode up to?

Quote from: caress on March 31, 2007, 09:17:58 PM
maybe a cap to ground at the end
what would this achieve?

Quote from: caress on March 31, 2007, 09:17:58 PM
send the collector of one transistor to the base of an earlier one
again, what would this do? would you have this as an additional connection or as a sub for the other collector-base connections.

Matt
Title: Re: Weird pedals
Post by: caress on April 02, 2007, 10:53:09 AM
all of those "mods" that i offered may or may not do something interesting... 

using feedback is super simple - wire the input to the output with a switch and pot in between.  this may do nothing, create some subtle instability or just start the pedal oscillating.

adding diodes...just experiment with this.  you can add two diodes (ge, si, leds) in a feedback loop (neg end of one facing the pos end of the other) from the base to collector, from emitter to ground, from any point in between two transistors to ground, after the last .01uf to ground...?  i don't know if this will do anything significant...might just add some different harmonics in the clipping?

a cap to ground after the last .01uf makes one of doug's other pedals (garagefuzzz) freakout and start oscillating and creates octave drops, etc...so i figured it's worth a try.

the collector to base is just another form of a feedback loop.

EDIT: *most of these additions will make a pedal kind of freakout or start oscillating in some way...maybe this is useful to you , maybe not.  it's worth noting, too, that in the past i've added feedback loops and diodes to ground in pedals and the diodes act as a gate for the oscillation so that it stops when you're not playing.  that was definitely useful...*
for any of these, i would recommend trying some different ideas out without actually soldering anything.  if you find something you like, add a switch or a pot.  i wish i could technically tell you what was happening in these circumstances, but i don't know enough to say...i'm just trying random shit out.   :icon_wink:  hope this helps...?
Title: Re: Weird pedals
Post by: mattpocket on April 02, 2007, 11:03:00 AM
trying random shit out... this is the way forward!

I love experimentation... if you do it to a toy, its arseing around with circuitbending, if you do it to a pedal, its design! haha
Title: Re: Weird pedals
Post by: doug deeper on April 02, 2007, 01:58:11 PM
the cap to groud thing only work in the garage fuzzz because the last stage is a negister (a type of oscillator)
and with out the extra cap its set to oscillate just out of hearing range.
Title: Re: Weird pedals
Post by: caress on April 02, 2007, 01:59:32 PM
ahhh ok
Title: Re: Weird pedals
Post by: 2wm on June 12, 2007, 06:44:24 PM
hello. i'm new here and i just attempted to make a pcb design for the random number generator. can you guys tell me if this looks right?

<a href="http://photobucket.com" target="_blank"><img src="http://i22.photobucket.com/albums/b344/2wm/rng.gif" border="0" alt="Photo Sharing and Video Hosting at Photobucket"></a>
Title: Re: Weird pedals
Post by: mattpocket on June 13, 2007, 03:26:43 AM
The trace coming down from C3 heading to the pot/feedback resistor is going to ground. This should not be the case. Also the grounds from Q1 & Q2 go to one trace, and then there is a ground trace running underneath. This is unessecary. You could fill in the space to make a larger ground plane, or just remove the top trace and connect the grounds to the bottom one. The way in which you have connected Q3 and Q4 is also a bit suspect. You have connected the emitters and then took the emitter of Q3 to ground. This might cause problems, although I am unsure of how. I would try to make a more direct route to ground.

I dont know if you know this, but when there is a "hump" in a schem where two "wires" cross it means that they are NOT connected. If there is a dot or no "hump" then they are connected. This could be why you ran into problems with the feedback section.

The feedback resisitor is a problem when creating a small layout. I made a really tiny layout for this, unfortunately I have lost it. It involved bending the transistor legs so that they are in the triangular position (rather than in line). In this case you can then "thread" the feedback loop through the legs of the transistors.

You also dont need the connection between r9 and c4. just connect r9 to the collector (as it is now), leave c4 where it is and just break the trace as shown on my drawing.

R6 also needs to be connected to the collector of Q3.

The feedback pot should also have two of the pads connected together although there is an easier way around this which I talk about below.

I have doctered your layout to show you where you've gone wrong. The change will mean you need to wire your pot differently. To make a variable resistor (as is required for the feedback loop) you wire one outside lug to the middle lug. Then just take one wire from the middle lug, and one wire from the outside lug (this must be the one that isnt jumpered to the middle lug). This means you only need two pads on the pcb, instead of three (as one connection is made at the pot).

You have also put three pads on for the volume pot, when you only need two. One pad by c4 (which you already have) and one pad on the ground plane (which you already have). One outside lug is connected to each of these pads, and the middle lug then becomes the board output which you wire to your stompswitch.

Also here is some advice about pot lugs on schematics that someone gave to me:
QuoteIf they are not numbered on the schematic then it is not certain, but most of the schematics here use a convention that the lugs are numbered 1,2,3 from the bottom to the top:

  | 3
  |
  \
  /
  ---- 2
  \
  /
  |
  | 1

Then if you are looking at the back of the pot with all lugs pointing down, they are numbered 1,2,3 from right to left.

Take a little look at this, I might have made mistakes too, its pretty early, I havent finished my coffee and just got to work! haha

(http://i18.photobucket.com/albums/b132/ukuleleboy/rng.png)

Hope it helps,

Matt

Title: Re: Weird pedals
Post by: Dan N on June 13, 2007, 04:43:36 AM
Whille your pot lug numbering is correct, lug #1 should go to ground so the volume gets louder when you turn clockwise.
Title: Re: Weird pedals
Post by: mattpocket on June 13, 2007, 05:30:35 AM
Lug one does go to ground?  ???
Title: Re: Weird pedals
Post by: Dan N on June 13, 2007, 05:40:29 AM
Quote from: mattpocket on June 13, 2007, 05:30:35 AM
Lug one does go to ground?  ???

Yes. You have it going to C4. Your way will still work, but it will get louder as you turn counter clockwise. Maybe more fun that way?
Title: Re: Weird pedals
Post by: mattpocket on June 13, 2007, 06:42:07 AM
Oh damn it, you are right! haha

I drew it the other way round to begin with and managed to convince myself that I'd got it wrong! haha Oh well, it was early.

2wm: Swap the two outside lug connections of the volume pot. Then I think my layout changes are correct.
Title: Re: Weird pedals
Post by: 2wm on June 13, 2007, 08:28:48 PM
first off, thanks a lot for all the help. i really didn't expect much a response but this is awesome. i definitely missed some things and i found the schematic really confusing. it looked simple until i started this project. i tried building it on perfboard and that didn't come out so well.
so i thought i'd try building a pcb for it which will be my first homemade one. i'm working on a couple of other weird noisy ones that i'm going to put in an atari junior case. maybe it'll look like i'm using an atari for a pedal.


 

Title: Re: Weird pedals
Post by: mattpocket on June 14, 2007, 03:45:49 AM
That will be really cool, keep us updated!
Title: Re: Weird pedals
Post by: mattpocket on June 29, 2007, 08:04:11 AM
Hey guys. I put my layout for verification in a new thread if anyone's interested?

http://www.diystompboxes.com/smfforum/index.php?topic=58763.msg457907#new (http://www.diystompboxes.com/smfforum/index.php?topic=58763.msg457907#new)

Matt
Title: Re: Weird pedals
Post by: Jaicen_solo on June 29, 2007, 05:55:57 PM
Those RNG samples aren't working for me at all, can anyone point me to alternatives? The descriptions sound like just the sort of thing i'm interested in!
Title: Re: Weird pedals
Post by: ambulancevoice on June 29, 2007, 06:54:28 PM
what samples? you mean the ones of midfielectronics.com?
Title: Re: Weird pedals
Post by: Jaicen_solo on June 30, 2007, 02:37:00 AM
Yep, those ones!