0415 Guitar Synth

10/9/2015

Update 2015-10-09
The new 0415 Guitar Synth is done and PCB's are now avaliable in the shop! :)
A verified vero layout added to the bottom of this post.

This is a simple but fun pedal that transforms the signal into a square wave, up to five octaves apart: one or two octaves up can be mixed with one or two octaves down for super synthy sounds.

What makes this special is that the octave up part is based on a frequency controlled oscillator so it doesn't scramble chords like usual octave circuit and it tracks well over the entire fretboard. Compared to the Arcadiator it sounds less like a fuzz and more like a pure synth. It can be very controlled, but also make superglitchy sounds.

Populated prototype PCB

In case you are wondering about the name, it has nothing to do with the CD4015 chip used. It's the birthday of my dog. :)

One of my dogs, Wookie (a bearded collie)

I made a quick recording of a cheesy "blues". The settings on both tracks were one octave down and two octaves up.

This circuit is basically a light version of a upcoming pedal that will be called "into the Unknown Guitar Synthesizer". It's based around the same chips, but it will be a monster with 8 pots and 3 switches... More about that one later.

0415 guitar synth vero.png
File Size:	282 kb
File Type:	png

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41 Comments

anders

9/3/2015 03:54:53 am

Sounds great, looking forward to build this on vero.

julilectric

9/4/2015 01:46:23 pm

This! Is! Awesome! Waiting for it.

Julungas

9/5/2015 02:28:48 pm

Como siempre impresionante! yo estoy trabajando en algo similar pero sin octava, es pura diversión el CD4046,
Saludos

Juri link

9/8/2015 12:37:38 am

Wow! That thing sounds stellar! I gotta build it ASAP!

Sergio

9/11/2015 09:39:16 am

Sounds so good! Do you think this could be joint to a ribbon controller of this kind? This would be amazing.
https://youtu.be/r1PD7NY1z-8

hymenoptera

9/16/2015 08:46:10 pm

Wow, this sounds great! Count me in for a PCB. I want to build this one!

Shane Cole

10/7/2015 03:11:06 pm

Wow!Sounds awesome!
How is it coming along and when will a vero layout be published?

Fredrik Lyxzén link

10/7/2015 03:39:07 pm

I will verify a vero layout tomorrow and the PCB's for the webshop is arriving any day now, so it's very close. Hopefully I will be able to post everything before the weekend. :) cheers / Fredrik

Kris

10/9/2015 03:04:15 pm

Totally awesome man another great design can't wait to see that pedal
Full of chippy goodnes !! Loving it

Press start to advance :p

Shane

10/11/2015 04:47:15 pm

Awesome!Adding this to my build list!

Brian Downey

10/22/2015 01:43:41 pm

I want to hear more about the "Into the Unknown Guitar Synthesizer". The little guy sounds great, can't wait to hear what its big brother can do.

11/2/2015 01:03:19 am

i built it
but if i use with buffer sound is not stable
What should I do?

11/2/2015 03:05:01 am

Hi,
Sorry to hear that. Did you build the vero of the pcb? I've used my 0415 PCB with a buffer in front (a boss tuner) without any problems. Does it help to adjust the sensitivity trimmer on the board? Maybe it can help to have short as possible and shielded input/output wires.

11/2/2015 11:28:49 am

i use schematic and make pcb with eagle cad.
when i play it with tuner or boss pedal sound is noisy
but when i put a guitar direct to it sound is very good. i love it

William

11/14/2015 01:03:26 pm

Hi, wow this sounds great, so I started to build. But I only get a high pitched signal, no guitar signal or something else. Is the vero layout verified? Or do you know what could be wrong?

william

11/14/2015 01:31:16 pm

Whoops, I found the mistake!
It seems the quality of my veroboard is pretty bad. One of the strips was broken. And for now... play!!

11/15/2015 04:51:44 am

yikes!... it's still not right. The mix acts as volume and octavedown switch doesn't do anything. Ideas for fixing this are welcome!

11/15/2015 08:44:39 am

Hi William!
Seems like the octave down portion isn't working properly for you. Check that the link between row 7 and row 20 is connecting (on the left side). Other than that it's hard to tell where the problem can be. Try reflowing the solder and look for solder bridges, the usual suspects :)
cheers / Fredrik

11/16/2015 10:33:12 am

thanks, I will check that tonight!
Also, this is the first pedal I did with a new brand of solder. I don't like it very much. And maybe that could be the problem.

11/22/2015 09:39:56 am

Are you using a bass on the prototype demo?

11/23/2015 02:13:27 am

I'm using a guitar in the demo. With the blend turned counter clockwise you hear one or two octaves down, and with the blend turned clockwise (from around 3 minutes in the video) you hear one or two octaves up, depending on how the switches are set. Cheers / Fredrik

11/23/2015 07:28:27 am

Sounds great!I have the stuff to do a vero build,just haven't got around to it yet.Any changes I might need to make if I do decide to build it for use with a bass?

11/23/2015 02:47:06 pm

Cool. You could try a bigger output cap (the 100nF that goes to volume 3) , like a 220nF or even a 1uF elecrolytic (with the negative side facing the output) if you want to make sure that no lowend is cut at lower volume settings. Cheers / Fredrik

11/23/2015 07:34:19 pm

I'll be sure to socket and play around with it.
Thanks!

1/22/2016 06:53:58 am

I'm having wired issues too.Did this on vero.Am getting a the high pitch tea pot sound.I can dial it out with the trimmer,but then the synth just starts going into automatic mode and making random synth effect even when guitar strings are dampened.Any thoughts?

1/23/2016 01:05:43 pm

Hi Shane,
Make sure your input and output jacks are properly grounded with the circuit ground. I recently had an issue with oscillation because of that, so it´s the first thing that came to mind. If it doesn´t help, check the usual suspects, solder bridges, jold joints or bad CMOS chips.

1/23/2016 02:38:01 pm

Checked the usual suspects first and all is good there.
So I will try to box it.Maybe the grounding issue is because I just have it connected to a test box.Or if it's a bad chip that will be easy to fix since they're socketed.
Thank you!

Peeps

4/5/2016 10:24:40 am

C5 appears to be missing from the vero.

Nordfalke

10/1/2016 10:40:51 am

Hey

I got the kit from Musikding.de cause it sounds awesome in the Demos, but now that i mounted it the output is silent.

i cheked all of the wiring, boosted the input and measured around on the bord, but could not find any faulty parts. Do you have some testpoints or somthing else to help me?

Thanks in Advance.

10/23/2016 06:59:03 am

Hi Nordfalke
I totally missed your post because I didn't get an email notification about it.

Sorry to hear that you are having trouble with your kit. It's hard to tell what the problem can be without more info. I know some kits were shipped with a CD4051 insted of a CD4015, so make sure you have the right chip (otherwise contact musikding and they will send you a replacement). Otherwise it could be a jold joint somewhere or a defective chip. If you can make an audio probe I can guide you through the signal path. Please email me at parasitstudio@gmail(dot)com for further help.

Best regards
/ Fredrik

Sam B.

1/21/2017 07:19:44 pm

Hello! I'm just getting into putting this together...i noticed the 100k trimmer. Is there anything special i need to pay attention to when setting this trimmer? or is it just a "by ear" adjustment....thanks!

1/24/2017 05:59:00 am

Hi Sam,

You can just tune it by ear. It will go from oscillating (sputtering) to more and more gated. It depends on your guitar output and how sensitive you want it to be.

For best results you should use a 200K trimpot. Are you building the stripboard layout? I just realized that I've never updated the stripboard layout trimmer value (I changed the BOM for the fabbed PCB months ago). I will update it as soon as I can.

Best regards
/ Fredrik

George

6/7/2017 07:46:41 am

Hi! just finished vero and it work and sounds really fun but i notice one strange thing - if i play on 2 octaves up position, notes on high E string upper than 15 fret all sound same, like slide from note down by the neck. And all the time notes from where it starts and stops are same. is it only mine work this way? :D

MANLAY Denis

10/27/2018 04:43:47 am

Hello fredrik.
Id juste need a little advice if you please.
i just bought a 0415 guitar synth kit from Musikding, i assembled it yesterday, everyting is working great, it's very funny, only the octave up switch doesn't work. It hasn't got any effect.
I tried to short its connection directly with a screwdriver but il doesn't change anything so i don't think the switch itself is the problem.
Have you got an idea where i should look at ?

thnaks for the help,

Denis

10/30/2018 07:10:25 am

Replied by email. :)

/ Fredrik

MichCAN

3/22/2020 03:30:59 am

Hello !
I have the same problem as Denis, i bought the kit from musikding. It sound very good but the oct up switch doesnt work. I verified connection
SW1>R14>4015(pin12) =OK
SW2>R13>GND = OK
SW3>R15>13 = OK
I looked on the vero circuit and it seems that the oct up SW2 is connected to CD4049 (pin 9) and not to the gnd. Is it the problem ?
Is it a common issue ?
Thank you,
Michel

Radical CJ

4/26/2020 08:56:40 pm

I thought I'd try the Vero layout for this one. The octaves up sound great but I'm having the same issue as William (circa. 2015) with no octaves down. Looking at the PCB version and schematic I can see there are some potentially significant differences.

C5 is missing as noted above, but there are also only 12 resistors on the Vero (when the PCB has 20!). One of the ones missing is a 100k pulldown from OctDown SW 2.

No-one else online seems to have this no octave down problem except william and I, but if I discover the reason I will post an explanation here for posterity.

4/27/2020 10:45:01 am

I have no idea why the octave down won't work. That part of the schematic is very simple and is made up of halv the CD4015 (and the chips seems to be fine, since the octave up is working), one CD4069 inverter and the switch. It gets mixed in via the 100K resistor that goes from the CD4015 pin 10 (to row 10 with the mix3 wire connection). Perhaps check the value of that resistor and that it goes from the right pin on the chip?

The reason why the PCB and vero layout is different is because the vero layout is version 1.0 and the PCB layout has been through some changes, like adding detune modes (to a fifth). The PCB's usually keep going through revisions and improvements, but I rarely have the time to update the vero layouts to the current version aswell.

9/18/2020 01:59:02 am

It wasn't an issue with the layout, just a damaged component that took me a while to identify. This circuit is a lot of fun! Thanks for sharing the schematics and vero layouts, shipping pcbs to Australia is usually a bit expensive (and currently not available).

Nathan

9/17/2020 06:49:48 pm

Hi, I just built this pedal on stripboard and have no output, just a high pitched screech. the knobs and toggles have no effect. I cant find any Cold Solder joints or bridges. any ideas?

Thanks

Gabriel Marsh link

1/18/2021 05:31:41 pm

Great reead thank you

0415 Guitar Synth

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