=== ALL NEW WAVEFOLD-FUZZ === WITH SOUND SAMPLES ===

[iainpunk]

so i was tinkering with asymmetric wave folding and found a way to make it just right in my opinion, here's the schematic.


it uses a battery pack of 4 AA batteries to create +3 and -3 volt. this makes the design a lot easier, if you decide to do it with a standard 9v, id suggest to use an op amp buffer for the Vbias, to keep the impedance low.

here are the sound samples. the number after 'vol' is the setting on my guitars volume knob, yes it goes to 11
https://soundcloud.com/iain-schmaloer/sets/batman-distortion-wavefold-fuzz

cheers, Iain

[Rodgre]

Sounds fantastic! Like a cross between a Prunes & Custard and an octave fuzz. Must build!

Roger

[iainpunk]

yeah, now i look up the prunes and custard, the way its working is very similar, but has some fundamental differences, like asymmetry in its gain and one side clipping near 0V on its way back.

i was kinda aiming for a Jesus and Mary Chain kind of sound, really breaking the sound appart and screaming your face off!!


I SEE I FORGOT A COMPONENT ::::::::::: UPDATED SCHEMATIC :::::::::::: RED LED :::::::::::::::::::::

without the red LED it sounds less compressed and cleaner, way less distortion on the sound, partially clean, not in a good way, its like a fizzy mosquito and clean mixed.

cheers, Iain

[willienillie]

I'm confused by this part of the schem:



Is that bottom diode shorted?

[iainpunk]

no, thats also an oversight in my drawing, ill repair it right away

[Gus]

have you seen this thread
https://www.diystompboxes.com/smfforum/index.php?topic=100633.0

[iainpunk]

have you seen this thread
https://www.diystompboxes.com/smfforum/index.php?topic=100633.0

you have already showed my the thread like 2-ish years ago.
https://www.diystompboxes.com/smfforum/index.php?topic=121904.0;topicseen#lastPost
that's some nice consistency there

i got the inspiration for the temporary name here
https://www.diystompboxes.com/smfforum/index.php?topic=122934.msg1161018#msg1161018

cheers, Iain

[Gus]

I forgot I did that

Is is good to see experiments with not "standard types" distortion

[iainpunk]

I forgot I did that

Is is good to see experiments with not "standard types" distortion

yeah, i found this when i was just experimenting a lot, but then i got past it. i recently started listening again to the Jesus and Mary Chain and i love the noisey vibe of the shin-ei superfuzz, but a superfuzz doesn't feel very dynamic, so i got back to the wavefolder and started tinkering to get that dynamic feel in my sound. another advantage is the amount of harmonic content i get with only a 10x gain.

and i changed a resistor for a bit more gain

ill be adding a bridged T mid scoop and a bandpass filter on a switch for tone 1 and tone 2. no volume control. no gian control, just a bypass

cheers, Iain

[John Lyons]

So how are you doing the Vbias at 3v?

[willienillie]

+/-3V bipolar supply.

[iainpunk]

So how are you doing the Vbias at 3v?

the wave shaping didn't like unbuffered Vbias, and i wanted to keep it to a single DIP8 IC so i decided on a bipolar supply. this also eliminates the need for decoupling capacitors. this all adds to the ease of design.

cheers, Iain

[Steben]

It sounds really badass. I rather call it the Joker 

[Marcos - Munky]

Imo it sounds very interesting, and it worths a try. I have two a question:
1- I see no caps at all. Where are them?
2- from your soundclip, something is happening to change the sound, but I see no pots on the schematic. Is the guitar volume causing the changes on the soundclips? Edited: found the answer on the 1st post.

Edited again: ok, so a few more questions:
2- you said it don't like unbuffered vref. Why? What happens when you use a unbuffered vref? I'm not good on theory, so I don't really know what happens.
3- did you tested it with a 9V power supply using a buffered vref? Since the standard voltage for pedals is 9V, it's a better idea to adapt it to be compatible with the standard voltage (even if that means using a extra opamp).

[PRR]

> I see no caps at all. Where are them?

It is possible to design audio amplifiers without caps. If also avoiding transformers (do the same thing differently), then there are some real limitations. One-side supply won't work; high audio gain makes large DC errors (upsetting subsequent stages).

[iainpunk]

Imo it sounds very interesting, and it worths a try. I have two a question:
1- I see no caps at all. Where are them?
2- from your soundclip, something is happening to change the sound, but I see no pots on the schematic. Is the guitar volume causing the changes on the soundclips? Edited: found the answer on the 1st post.

Edited again: ok, so a few more questions:
2- you said it don't like unbuffered vref. Why? What happens when you use a unbuffered vref? I'm not good on theory, so I don't really know what happens.
3- did you tested it with a 9V power supply using a buffered vref? Since the standard voltage for pedals is 9V, it's a better idea to adapt it to be compatible with the standard voltage (even if that means using a extra opamp).

1> i have designed it with bipolar supply to avoid capacitor use, im going to add a superfuzz style tone1/tone2 option that has a bridged T filter and a resistor divider, those will be the only capacitors.

2> un buffered Vref has a relatively high impedance, if the diodes have a series impedance, the post-fold gain gets lower and the wave folding can become clipping or soft clipping depending on the impedance. if the vref is capacitively coupled, the capacitor will change its DC value because there is a different positive and negative current, lobsiding the voltage over time, something you don't want in this case because it lessens the effect and softens the sound in an unpleasant way.

3> yes, i tried it with a buffered Vref, it works the same, i A/B tested them and they sound the same but i have a bunch of AA battery holders that have 3 wires for bipolar supply, so that takes away the need for a 3rd opamp and AA's are cheaper than 9V's, if i were going to make a production run of this pedal, i would definitely make it run 9V, and i'd add an active tone control and oct up / wavefold switch... features to make it sell easier, but im not, its going to be a one off and its going to have no features, no knobs, not even a volume, only a bypass and a tone switch, i build one trick ponies, that's what i like to do, make something that does 1 thing exactly the way i want, and nothing else. if i want to change the sound, ill just combine it with other pedals.

> I see no caps at all. Where are them?

It is possible to design audio amplifiers without caps. If also avoiding transformers (do the same thing differently), then there are some real limitations. One-side supply won't work; high audio gain makes large DC errors (upsetting subsequent stages).

yeah, i noticed in other experiments with bipolar supply that if the gain is more than 30x there should be some DC blocking caps in the feedback loop to not make the bypass pop, at least with the LM358. lucky that the gain is only 10x, the pre-fold gain of a wave folder is 1

cheers, Iain

[Marcos - Munky]

This one trick pony does it's job very well!

I think on using a opamp vref to make it more friendly for thers to build it. I mean, you're right on AA's being cheaper than 9V's, but some people uses wall warts only, and for a 1590A it's just a impossible thing . It's possible to use a charge pump to get bipolar power suppy, but it's easier to just add another opamp for the buffered vref because it's cheaper.

So, if I get it right, to use a buffered opamp I have to move the two ground points to vref, add an input cap, a cap after the output of the 1st opamp and a output cap. That's correct? I don't know if a cap at the input of the 2nd opamp is needed.

[iainpunk]

This one trick pony does it's job very well!

I think on using a opamp vref to make it more friendly for thers to build it. I mean, you're right on AA's being cheaper than 9V's, but some people uses wall warts only, and for a 1590A it's just a impossible thing . It's possible to use a charge pump to get bipolar power suppy, but it's easier to just add another opamp for the buffered vref because it's cheaper.

So, if I get it right, to use a buffered opamp I have to move the two ground points to vref, add an input cap, a cap after the output of the 1st opamp and a output cap. That's correct? I don't know if a cap at the input of the 2nd opamp is needed.

first of all, this is not a 'fully decked out' schematic, its more of a 'circuit snippet', i left off all features i could, even the volume control. im going to add a mid scoop switch when i get back home monday that's the only external control my version is going to have (also a bypass of course). but a tone control could be added, and whatever features you want. you could add a gain control for the hell of it. if you make the gain high enough, it becomes a more traditional fuzz sound, until the note begins to die down.

i like to use wall wart daisy chain power for the power hungry pedals,digital pitch shift, phaser, a badly designed overdrive i made etc... but this uses only one LM358, which uses very low power, so AA's go a really really long way.

1590A? im going to put it in a big cigar box, and paint a bob ross style work on the front, mixed with MC Escher influences of course.

yes, if you do a buffered Vref, you put those ground connections to the Vref and a big-ass capacitor in front and after the whole thing. don't put a cap in between the two stages, well, you could.... hell, do whatever you want, experiment with it!! try different diodes and different resistor values, or skip one or both diodes in the negative feedback loop. i loved to tinker with the basic topology. this is what i found to be the best sounding, but i strongly encourage to tinker and experiment

cheers, Iain