Raygun Youth Chaos Fuzz

8/3/2014

Here's another original of mine, the "Raygun Youth Chaos Fuzz". It's a very synthy and totally insane octave fuzz - an aquired taste for sure, but noise freaks should like it. :)

It's loosley based on a circuit by Nicolas Collins from his excellent book "The Art of Hardware Hacking". A comparator turns the guitarsignal into a squarewave that triggers a Phase Locked Loop Oscillator. I could go on explaining how it works, but it's better that you just listen.

This circuit works best with the neck-pickup and tone turned down on your guitar. In the video i'm using humbuckers (Gibson SG) and i'm playing the same riff over and over so you can get a sense of how the circuit reacts in different modes. The pot called "disorder" slows down the PLL tracking and goes from fast to slow. When tracking is slow it's mostly noise... The first mode is straight analog comparator fuzz and thus not effected by the tracking control.

The name Raygun Youth Chaos Fuzz is a tribute to one of my favourite punk-bands. Yes, I know it's a bad pun, but I couldn't help myself... :) Aslo, the word Raygun is kinda fitting with some of the sounds it can make. Two thumbs up to anyone that understands the graphics play...

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33 Comments

Ian

1/7/2015 12:25:31 am

Hi

You can class the vero of this as verified. it works!
The vero for the Flawed Logic I cant get working however. See my comments on that thread...

thanks

Ian

Fredrik Lyxzén link

1/7/2015 05:02:18 am

Cool :)

Yes, a corrected version of the Flawed Logic vero is coming as soon as I can get some spare time.

cheers / Fredrik

David

1/10/2015 01:30:15 am

My build makes "sputtering" noises for lack of a better term. Is this normal? I don't hear those noises on the demo video. If used with a noise gate, the sputtering would go away.

1/10/2015 07:34:21 am

Hi David.
Sorry to hear about your problem. It should be quiet when not playing. Is it sputtering in the first position (stun) aswell? Try probing your build (I usually just take a wire connected through a 1uF cap and a voltage divider) to listen where the noise appears. Opamp stage 1: Pin 1 of the TL072, should put out a gated square wave fuzz, and op amp stage 2: pin 7 of the TL072 should put out a very filtered/low-passed sound.

1/10/2015 10:16:34 am

Thanks for the quick reply :)

It sputters in positions 2,3, and 4. Position 1 seems ok.

I've got the circuit on the breadboard and I'm still getting the sputtering. Using a probe, I'm getting good signal on pins 1 and 7 of the TL072.

In position 2, I can hear effect signal and sputtering on the 2.2k resistor side of the 100nf cap. (Strangely enough, I don't hear the effected signal on the CD4046 side of the 100nf cap)

I've tried different CD4046 chips and I get the same problem.

1/10/2015 05:52:59 pm

That's strange. The filter at op-amp stage 2 along with the 100K resistor going to ground at the CD4046 input should prevent false triggering that could result in sputtering, so there must be a different problem. Don't know really what to look for then. Sorry, maybe you could ask in the Raygun thread on freestompboxes, since a few people there has built it with success.

1/10/2015 07:22:05 pm

I think I've solved the problem. I think the sputtering was due to the way I was playing the guitar. Once I started muting the strings better and playing single note lines, the sputtering cleaned up well.

I think that when I first turned on the circuit, I wasn't used to the way that the notes decay. I assumed there was some problem, when there wasn't one.

I'm now getting some very useful sounds out of the pedal. It helps to play in certain areas of the fretboard.

Thanks for all the help!

Matt

3/29/2015 06:23:10 pm

Hello there,

Another endorsement for this device having made a veroboard circuit yesterday. To my surprise the thing worked immediately! Amazing really as my shakey coffee fingers are not ideal for stupid tiny veroboard soldering and my desolderer seems to have gone missing. Testing after midnight did not make me popular with the others in the house. This thing is truly horrible! Well done sir! Tempted to try another of yours next, maybe the Corruptor...

3/29/2015 08:50:52 pm

Thanks! I'm glad you like it. :) Haha, testing after midnight is dangerous. I've done it many times. :P

Thorsten

12/1/2015 04:53:53 am

Great Pedal, I just finished soldering and it worked immediatly. I've done a little MOD some floks might like too: I used some previously unused pins of the rotaryswitch to select one of four LEDs.

Not my last pedal of yours!

12/1/2015 05:09:51 am

Hi Thorsten,
Thanks for the build report. I'm glad you like it :)

Shane

12/9/2015 12:02:21 pm

Whoa!This is a truly insane fuzz!Just finished up a PCB build of it!
While my 3 year old daughter wasn't nearly as stoked as I am,I really love this effect!
My daughters reaction was to run in the music room and say"Hey!That noise hurts my ears!"
So I dimed my volume!

12/9/2015 03:37:43 pm

Haha. :D I'm glad you like it! It's not for the faint of heart :)

Wizombie

3/22/2017 10:36:17 pm

Dude let me just start by saying holy fing sh@t balls batman!,,, before a built this in the vero layout I had a face ............ now I have nothing due to my mind exploding,,,,,
Cheers

3/28/2017 01:44:20 am

Haha, thanks! That's probably the best "review" I've ever gotten. ;) Cheers / Fredrik

Panxo

4/6/2017 04:49:51 pm

I recently made a clon of this little monster, so i started to hack the circuit and found something interesting sounds... i just put simple switches between the Input point and pins 1,2 or 3 of the rotary switch, and i get diferent types of siren-like sounds. I will add momentary switches in my pedal to use this noises while i play my guitar This circuitl its an ears destruction weapon!!!

4/12/2017 04:55:08 am

Hi Pnaxo,
Thank you for the build report. Nice to hear that you found a way to make it even more noisy. :D The CD4046 is a wonderful chip, full of possibilites. Cheers / Fredrik

Dimas

10/14/2017 07:28:16 am

Hello. I built this wonderful box of chaos). This is really something! But there is a problem: at positions 1 and 4, everything works fine, for 2 and 3 it also works, but with some kind of clipping. Built theremin fuzz
it works, but the same problem.Tell me what might be the reason?

Brett

12/2/2017 04:16:41 pm

I built one finally. It's such a great pedal, lots of fun. A couple of the settings remind me of the Repeater PLL 2.0.

Thanks for sharing your designs with us Fredrik. I bought an Into the Unknown board but I haven't built it yet. I'm very excited for it. I want to buy an Xor'Cist too.

12/4/2017 01:48:17 pm

Hi Brett,

Awesome. I'm glad you like it. :)
Cheers / Fredrik

Tadashi Takahashi

11/26/2019 04:02:52 am

Hello My name is Takahashi. I made Raygun Youth Chaos Fuzz. The operation seems to be fine, but the stun sound is strange. It wo n’t sound like you ’re playing on video. Specifically, it is a blurry sound with no sharpness. There is no gate feeling. What is the cause?

11/26/2019 02:49:25 pm

Hi Takagashi,

The stun output comes directly from pin 1 of the opamp, which should act as a comparator (square wave generator). There is not many components around that section of the circuit, so I recommend that you try a different opamp (IC2) first.

If that doesn't help, then make sure that R2 is a 1M resistor, and do a visual inspection of the board and look for shorts around C1, C2, R2. You can also try reflowing the solder on those components and the IC socket for IC2.

I hope that helps. :)

squaresolid link

4/11/2020 03:56:06 am

Hi Fred,

I'm trying to make this pedal following your instructions on the pdf.
It's said to cut off pin 17 of the 4046, but it's 16 pin IC :D
Which pin do you mean by that?
Thanks!

Fredrik Lyxzen link

4/14/2020 02:53:54 am

Hi!

Oh, ops! Thank you for pointing that out. It's supposed to say, pin 15, not pin 17. Cheers / Fredrik

4/24/2020 12:37:43 pm

One more question tho, in your design, the feedback resistor 100k on IC2B of the Opamp, can you explain to me why it's connected to the input resistor rather than the inverting input of the op amp?
I'm trying to modify this circuit and found my build has very short tails when the output is using either of the 4046. Cheers!

4/25/2020 07:45:21 am

The second op amp stage feedback resistor follows the typical topology of a second-order MSB (multiple feedback) lowpass filter, so google on those and perhaps you'll find a good explanation. I've never analyzed that part of the schematic in depth, except for boring component calculations for cutoff frequency.

For the sustain, there's a couple of things you can do. First, try removing the 10K input resistor to the CD4046 (that goes to pin 14) and replace it was a 100nF capacitor. Also remove the 100K resistor that goes to ground (from the CD4046 input/pin 14).

It will ensure that the internal amplification and schmitt trigger inside the CD4046 will be activate (so it will handle much lower amplitude inputs). Something I wasn't aware about when I designed this circuit (the 4046 datasheets are very vague about this). So it should have the same sustain as the comparator output. Let me know if you are having good results with this mod, if you test it. Cheers / Fredrik

4/27/2020 07:25:56 am

Thanks for the explanation!
Let me get back to you in a few days and I will let you know how it works!
Cheers!

2/19/2022 08:20:16 am

Hi Fredrik! I tried this mod since I wasn’t getting signal on higher notes. It definitely solves that issue, however, I’d like to tweak the gate level since even when not playing, I’m getting noise. How could I achieve this?

Zach

11/30/2021 07:14:29 pm

Hello! I have built the vero version of this pedal and I'm getting a great sound for stun. I'm getting extremely low output for positions 2 and 3 on the switch and nothing for four. I'm troubleshooting with an audioprobe and I'm getting signal before and after C2, but I'm getting no signal at all after R3 (47k) Is that typical?

Nick

7/21/2022 07:22:22 am

I built the Raygun on Vero, and I just have one problem. Position 1 works fine, but when I switch to either 2-3 or 4, I get siren noises. They go away when I mute the strings, but it comes back and varies. Underneath those noises, the modes seem to be workin as intended. Any idea where to look to first? Bad 4046?

8/7/2022 08:49:06 am

I posted back in November and eventually solved my problem. I had forgotten to cut a row. It had been marked on the front but just fully connected on the back. It works super well now.

I've built a lot of things and the problem is almost always with the build rather than the components. I'd go back, cut the rows, check over EVERY aspect and then go through with an audio probe. You can switch out the 4046 if you have an extra. Good luck!

8/15/2022 06:47:59 pm

Thanks for your reply. Visual inspection seems fine, but I'll do a deeper troubleshooting once I tried swapping the 4046 ;) (I had added oit to a parts order that should come in next week).

Matt Thrace

11/10/2022 06:22:34 pm

I built mine a few years back. Any screw ups i had were when i tried wiring up the jacks and switch properly as a total noob. An experienced eye straightened me up 30 seconds.. Just a vero build. Super fun! Fired it up last night and i was blown away by it. Theres definitely some doom to be found. Years later i still love this pedal. Thanks for creating this resource.

Raygun Youth Chaos Fuzz

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