analog style octave up at different interval?

[rove]

Lately I have built a lot of octave up pedals, or pedals that have a slight octave up as a by-product e.g. neoctavia, foxx tone machine, superfuzz, RM axis fuzz, scrambler, etc.  I was wondering if a similar concept as any of these effects could  be used to create a different interval upper note such as a third or fifth or whatever.  Not clean, mind you, but fuzzed out as the above listed effects. It seems like it would be possible...
I will of course search around, but wondering if anyone has experimented with making this type of effect.
thanks.

[Mark Hammer]

Unless you are going to go the digital harmonizer route, you need to start off with a much higher frequency version of your input signal and then divide that down with a counter chip.  There was a project article in Electronics and Music Maker a number of years back, that RG sent me a copy of and I sacnned and posted it on my site (http://hammer.ampage.org).  It is the E&MM Harmony Generator.  Word is that it works just fine, thought probably not for the faint of heart or novice builder.

[rove]

Thanks, Mark. I just downloaded the pdf and that looks to be about what I meant.  However, I was actually thinking simpler like a dedicated fifth fuzz.  I'll see what I can glean from that article, much appreciated. Not interested in the digital harmonizer route at all, looking more for a weird sound than a perfect harmony, but more musical than a ring mod and not an octave...

[R.G.]

The problem you get into is that generating a fifth up by analog means is either not multi-frequency (bad unless your playing is monotonous... ) or it is very complicated indeed.

The only reason that an "analog" octave up works is that we hear a 2:1 frequency ratio as an octave and full wave rectification makes ripple that's twice the frequency you feed it. It's a special case that does not work for other than 2:1, 4:1, etc.

A PLL tracker like Mark mentioned or the uC equivalent is really the only reasonable DIY-able approach that I've seen.

[rocket]

I think zvex claims that his machine tripples frequency (and that's what a 5th is, isn't it), and it does sound weird.
you have to mess up the signal not at the peaks as a clipper does it but near zero, like crossover distortion.