Octave Pedal.

[ConfusedGCSEStudent]

Hi everyone, I'm new. for my GCSE Electronics project I have chosen to make an Octave pedal for my guitar (Octave down, up, or both). I understand how some octave pedals work (the flip-flop square wave method used in this video: https://www.youtube.com/watch?v=64Wfz3MFZi0), but I am unsure how to do this with actual circuitry. Any help would be appreciated. Thanks in advance.

Sidenote: I am designing all circuits in Circuit Wizard 3, what ways would you recommend testing out circuits in the emulator? I.E. best way to put a sound through the circuit.

[nocentelli]

Welcome! A simple way to do the flipflop octave down with discrete transistors instead of opamps is the "Shocktave" drawn by Joe Davidson:

https://www.google.co.uk/search?q=shocktave&oq=shocktave&aqs=chrome..69i57j0l3.4130j0j4&client=ms-android-sonymobile&sourceid=chrome-mobile&espv=1&ie=UTF-8#imgrc=DCt4BI4GG23gRM%3A

The "green ringer" by Dan Armstrong is a transistor octave up:

https://www.google.co.uk/search?q=green+ringer&client=ms-android-sonymobile&espv=1&prmd=vi&source=lnms&tbm=isch&sa=X&ved=0CAcQ_AUoAmoVChMIrdanutatxwIVQVnbCh1magHk&biw=598&bih=279#imgrc=_R8enHiwVXXPRM%3A

You could try out connecting the guitar to a single bjt transistor buffer, splitting the output of this buffer to the two different circuits in parallel, then sum the outputs together for the output. I definitely advise getting a breadboard to try out your circuits, maybe one at a time to check you can get them working.

If you want to use IC chips, there are a few that can do one or more octaves down (cmos 4040, 4017) and octave up (4070). The way the Green ringer produces an octave up can also be done with transistors and a transformer, or with an op amp or two. Some DIY and project circuit names to Google are Escobedo digital octaver, Dwarfcraft robot devil, valve wizard U boat, gus smalley octave up sickbox.

Bear in mind these are all monophonic, and some are pretty dirty. It will not sound like the EHX micropog unless you venture into DSP (which is an area in which I have no experience).

Good luck with the project, call back with any questions.

[samhay]

^Sidenote: I am designing all circuits in Circuit Wizard 3, what ways would you recommend testing out circuits in the emulator? I.E. best way to put a sound through the circuit.

I don't know Circuit Wizard, but I would imagine you can generate a voltage source that outputs a sine wave of arbitrary frequency and amplitude.

[Gus]

I would suggest you do some web searches if this is for a school project.  You should be able to find the information.

[duck_arse]

(among others) the mxr blue box does flip-flop octaves. the 'rocktave' also, but better/more complex.

[ConfusedGCSEStudent]

Thanks everyone! I will do some more research.