Stompbox Schematics

How to build an analog pitch shifter for guitar? DIY stuff…?

How to make an stompbox that changes the pitch of a note, like the frequency? So to play a A4(440H) on guitar and to get an A5(880H). And how can the stompbox have a potentiometer to change the frequency, like a linear but for pitch not for volume or tone. Any Schematics, ideas?
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Changing pitch is a surprisingly hard thing to do, and basically impossible in an all-analog circuit. The closest you can get would be to use analog bucket-brigade devices and do some very fancy variable-frequency clocking… you don’t want to go there.

You can get an octave above by full-wave rectifying the signal. The good thing about this is that the circuit is really simple, the bad thing is that it only works on one note at a time. Playing a chord through it will sound like armageddon.

Here’s a circuit. I have seen simpler ones but I can’t find one online. Beware there is another octaver circuit that seems to be replicated all over the web, but it cannot possibly work.

http://www.fortunecity.com/tinpan/humperdinck/223/octave.gif

Sorry, link does not work due to website crappiness. If you are interested send me an email and I’ll send you some schematics.

@billrussell42:
What you just described does actually exist and has been used since the early days of electronic music. It’s known as a klangumwandler. Because it shifts the pitch of all the harmonics in the sound by the same amount the result tends to be very unnatural and dissonant.
Here’s one:

http://matrixsynth.blogspot.com/2009/04/360-systems-2020-frequency-shifter-bode.html

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