Pitch Shifter

[FlashBandit]

I want to build my own pitch shifter, and the only schematic I could find was the one on general guitar gadgets. I've heard it's no good, but I want to know if that was just opinionated. Anyone built it? Can you control how much the pitch is affected? up and down? does it maintain harmonic relations between notes? do you know of any better schematics for a good pitch shifter? I'm just looking for something similar to the digitech pedal, 8ve up and down. Schematics would be awesome!

Edited June 29, 2007 by FlashBandit

[curtisa]

The best pitchshifters use DSP's to perform complex mathematical functions in order to change the pitch of the incoming audio. The mere fact you have to use a DSP will put a high (ish) quality pitch shifter like the Digitech pedal well and truly out of reach to the casual DIY-er. It'd be more economical to just buy an off-the-shelf unit.

The datasheet for the chip used in the pitch shifter over on General Guitar Gadgets mentions that the sampling rate is 8KHz with a bit depth of 8 bits. That's pretty ordinary quality compared to modern pitch shifters. Also, the clock for the chip is based on an external resistor, so if your resistor drifts with temperature or age your pitch shifting will drift aswell.

I haven't built this pitch shifter, but based on the specs of that chip I prolly wouldn't bother.

[Sambo]

Pitch shifters that work on octave functions (ie up or down an octave) are fairly simple to achieve. Look for things like the MXR blue box, a couple of Dan Armstrong boxes (cant remember names off hand, but there's deffo an octave up one).

Schematics for some of the older boss oxtavers are available from various places online.

Anything further than straight octaves is a little more difficult. And to be honest, its probably cheaper to buy one of the behringer pitch shifters (they're not bad actually!).

S