The 0415 Guitar Synth

[Freppo]

Hi folks,

I just wanted to let you know that I just released a new original design called "the 0415 Guitar Synth".
It turns the guitar signal into a square wave with both octave up and octave down that can be mixed together.
The octave up is based around a Phase Locked Loop and it tracks well over the entire fretboard.
So unlike a normal octave fuzz, this one doesn't scramble chords and it can even do two octaves up.

Here's a short, kinda cheesy "blues" I threw together.. 
https://soundcloud.com/fredrik-lyxz-n/bitblues

More info, PCB, and demo video at www.parasitstudio.se

I hope someone finds this little circuit interesting
cheers / Fredrik

[Kipper4]

Excellent love it Freppo
So differant

[Mark Hammer]

Kind of in the same camp as the Crash Sync, albeit in a different and more flexible way.

Never used the 4015.  I assume it provides the selection of octaves.  Can pin 11 of the 4015 be used if one has a suitable switch, or are there just the two choices?

Is performance improved at all by sticking a small cap in parallel with R3 to tame the highs a little more, or does it lose something by doing so?

[Freppo]

Never used the 4015.  I assume it provides the selection of octaves.  Can pin 11 of the 4015 be used if one has a suitable switch, or are there just the two choices?

Yes Pin 11, and even pin 2 can be used for 3 or 4 octaves up...  But it's just too much to be useful. 
The CD4015 shift register works as four D-flip flops in series with the inverter from the output back into the data input.

Is performance improved at all by sticking a small cap in parallel with R3 to tame the highs a little more, or does it lose something by doing so?

I will not make a difference since the schmitt trigger output that follows is basically "immune" to any filtering before it.
C2 is enough, but it's just there to improve tracking alittle bit and stop oscillation. It does nothing to the tone.

[Dakota]

This is superb for two knobs and two switches. So many useful and totally synthy tones. Would take great to phasers and delays after it. 

[Quackzed]

sounds good man!

[aron]

Very cool! Sounds GREAT! Now don't take this the wrong way, but you kind of look like Bruce Lee. :-)

[Freppo]

Thanks! Glad you like it!

Now don't take this the wrong way, but you kind of look like Bruce Lee. :-)

Ehm.. That's because my avatar is actually a pic of Bruce Lee, not me.     

[~arph]

So unlike a normal octave fuzz, this one doesn't scramble chords

Nice little circuit, but surely it does not track chords... You'd either need DSP or a hex pick-up and six PLL' s

[Freppo]

Nice little circuit, but surely it does not track chords... You'd either need DSP or a hex pick-up and six PLL' s

You're right. It doesn't track chords. What I meant is that it doesn't sound scrambled like a normal octave fuzz do.
Insted you get some octave jumping, but simple two string power-chords can actually sound pretty good.

[Ben Lyman]

that's pretty much the coolest guitar synth I've ever heard, if I wanted a synth tone for my guitar I would definitely want that. Very cool indeed, good job 

[Freppo]

that's pretty much the coolest guitar synth I've ever heard, if I wanted a synth tone for my guitar I would definitely want that. Very cool indeed, good job 

Thanks. I'm glad you like it 

[stringsthings]

Really liked the demo video on your website.   Also looking forward to the "deluxe" version.   Gotta finish up the sidescroller first, but I can definitely see myself buying a couple of these synth PCBs in the near future. 

[FUZZZZzzzz]

I just found my 'mystery pedal' for the coming recording session thanks for sharing! sounds great.

This is probably the first pedal ever that makes even 'sweet child o' mine' bearable (yes i listened to your video). You should be applauded for that alone. You're just in time as well as I was just about to build the Bit Commander. I think that one will have to wait.

Have you tried it on bass?

[FUZZZZzzzz]

also, what does the 100k trimpot do exactly.. as in.. is it worth taking outside?

sorry.. I found half of the answers already.. i was looking at the vero, but on the pcb it reads sens trim..

[Freppo]

Thanks! Glad you like it
It sounds pretty cool on bass, but alittle more glitchy.

also, what does the 100k trimpot do exactly.. as in.. is it worth taking outside?

sorry.. I found half of the answers already.. i was looking at the vero, but on the pcb it reads sens trim..

Yes, the trimmer sets to input sentitivity, from very sensitive (noisy when just touching the strings) to more controlled/gated.
The expanded version that I'm working on will have that as a external control - works better with the features it has.
For this one I would leave it as a trimmer.

cheers / Fredrik

[Luke51411]

For the expanded version, are the chips the same? I'm going to place a mouser order soon for the ICs for this version and figured I would just double up for when the expanded version is released 

[FUZZZZzzzz]

So about the trimmer... just set and forget? Just dial it slightly over the noise threshhold? I will try to build it in a couple of days.

[Freppo]

For the expanded version, are the chips the same? I'm going to place a mouser order soon for the ICs for this version and figured I would just double up for when the expanded version is released 

Yes, the same chips but 4 insted of 3 chips:
1x CD4015, 1x CD4046, 2x CD4069

So about the trimmer... just set and forget? Just dial it slightly over the noise threshhold? I will try to build it in a couple of days.

Yes, pretty much set and forget. Adjust it after your guitar and taste (how much noise..)

[Luke51411]

For the expanded version, are the chips the same? I'm going to place a mouser order soon for the ICs for this version and figured I would just double up for when the expanded version is released 

Yes, the same chips but 4 insted of 3 chips:
1x CD4015, 1x CD4046, 2x CD4069

So about the trimmer... just set and forget? Just dial it slightly over the noise threshhold? I will try to build it in a couple of days.

Yes, pretty much set and forget. Adjust it after your guitar and taste (how much noise..)

Cool, thanks for the quick response! I love your circuits and will be boxing up a Corruptor soon!