Ladies and gentlemen allow me to present the
Slacktave, an all new octave down pedal I've been working on for a while. It uses a
CD4024 ripple counter to generate 1 or 2 octaves down that can be used on their own or mixed with a nasty comparator fuzz for a wide range of fuzzy synth like textures.
Here's the schematic
http://www.eskimo.plus.com/fxstuff/slacktave.pngand some samples, all played around the 5th and 12th frets
one octave downtwo octaves downfuzzfuzz plus 1 octave mixfuzz plus 2 octave mixThe basic idea of using the 4024 came from
Ken Stone's sub-oscillator and I've tried a few different ways of hooking it up to a guitar to get decent tracking, this is the first version that I thought was worth sharing. It uses a modified version of the fundamental extractor from the
Electrax guitar synth that Stephen Giles posted a while ago to drive a comparator that's hooked up to the clock pin of the 4024. The divide by 2 and 4 outputs are then used to give the octaves and these can be mixed with the comparator output. If my maths is correct the mix pot also acts as a variable highpass filter so as the octave is blended in more low end is rolled off the fuzz side which helps bring out the octave.
It tracks pretty well between about the 3rd and 17th frets and works best on the middle 4 strings. As with most of the these things you get the best results using the neck pickup with the tone rolled down, this gives the most stable octave down. However if you use the bridge pickup you can get an octave jumping effect.
This is still on the breadboard so if anyone's got any ideas for improvements I'd be happy to hear them. Any comments on how it sounds compared to the other octave downs out there would also be cool.