Octave Fuzz Overdose!
Seven Classic Circuits

These funky homemade pedals represent all the leading octave-fuzz circuits.

I had no idea I had so many octave fuzz pedals! I had no idea they sounded so different! And after spending way too much time auditioning and recording them, I have no idea when I’m ever going to be able to stand listening to them again! :noshake:

Naw, just kidding — I had lots of fun putting together this octa-fuzz fest. It features no name-brand pedals, just DIY clones based on old circuits. But hey, most of today’s octave fuzzes are also clones of old circuits.

In fact, imitation has always been the name of the game here. The Roger Mayer Octavia used by Jimi Hendrix was inspired by a circuit found in a British mixing console. The US-made Tycobrahe Octavia was a ripoff of Mayer’s circuit, though tone snobs tend to regard it as the superior unit. It’s certainly one of the rarest and most valuable stompboxes ever.  The name “Octavia” has also been slapped on many other variations of the circuit, including some particularly dismal models. The Prescription Electronics Experience and Lovetone Ultimate Octave are based on the Foxx Tone Machine. The Dan Armstrong Green Ringer was based on the Ampeg Scrambler, and I used the Green Ringer circuit as a jumping-off point for some of my own designs. The sincerest form of flattery abounds here.

If you make it through this seven-circuit survey, you’ll encounter most of the major players, and if you hear something that particularly interests you, you can build it yourself using readily available schematics, or buy a nice kit or boutique clone.

Now, don’t confuse this effect with modern digital devices that actually transpose the notes you play. Octave fuzzes use an electronic trick to cancels out much of the fundamental of each note, making the octave overtone stand out more prominently. The process is called full-wave rectification, and ever-knowledgable reader mwseniff explains it far more capably than I in a comment following my previous post on this topic. It’s an odd, glitchy effect that tends to require specific playing techniques for the best results. And for better or worse, it’s an effect that has so far been difficult to mimic digitally. Sure, some of the modeling boxes out there have interesting-sounding octave-fuzz effects, but they tend to score low on the analog-realism scale.

Check out the video. The post-mortem comes after, as post-mortems usually do. 

So who wins? Tough call! My favorites as-is are the Tycobrahe Octavia and the Foxx Tone Machine. The Octavia is a wild and crazy anarchy box full of sonic surprises. The Foxx Machine offers perhaps the most solid octave sound, plus an aggressive and startlingly modern distortion sound (if by “modern,” you mean 1994).

But even more intriguing to me are the circuits that could be derived from these originals. For example, the Green Ringer sounds rather anemic on its own, but preceded by the right boost stage, it’s a monster, as heard in the video’s final demo, where I paired it with a silicon-transistor Fuzz Face derivative. And I swear, someone somewhere is going to create an amazing update of the Ampeg Scrambler. Maybe you — unless I beat you to it!

Also: D’oh! I neglected to include one significant sound: The Univox Superfuzz, which also inspired the Z. Vex. Octane. It’s a loud, aggressive circuit with some of the muscle of the Foxx Tone Macine, albeit with a slightly less well defined octave effect.  Some great players swear by it. Maybe I can do an addenda after my ears heal and I can discern pitches above 1kHz again.

25 comments to Octave Fuzz Overdose!
Seven Classic Circuits

  • Tough call indeed! I think the Tycobrahe is the most familiar (if one can be familiar with aliens), but I’m really leaning towards the Green Ringer/Ampeg Scrambler. I thought Tim’s design offered some groovy sounds as well. I don’t really get the Blender, though…

  • Schrodingersgoldfish

    I like the Scrambler for really standing out of the crowd while staying musical…..ish.

  • s.huck

    Ok, so after 20 some odd years of playing I didn’t realize about the circuit thing. I’ve tried pitchshifters through a fuzz and it never sounded even close. Now I know why hahaha. Of course I’m also really just discovering what a great fuzz is all about. And yes I’m digging the Octavia! https://tonefiend.com/wp-content/plugins/smilies-themer/graemlins/imwithstupid.gif

  • mwseniff

    Great video demo, Joe. You obviously put a lot of time and effort in to creating thes great videos. I especially appreciate the on screen text it is much better than a voice over. My favoite was the final pedal that you designed and built yourself. This was a great way to hear and compare these various octavers. Thanks for your efforts it was very entertaining and informative.

    • joe

      Thanks Matthew! Regarding the lack of spoken word: I started doing it that way not because I wanted to be Harpo or Teller, but because guitars sound so crappy through on-camera mikes (and I’m to lazy to hook up an amp mike AND a lav mike for voiceover).

  • Jeff_H

    Love the demo, Joe!

    Tim Escobedo has his own URL now. His effects schematics (including the Rambler) are on this page: https://folkurban.com/Site/GuitarEffects-681.html I always thought the Jawari looked & sounded interesting.

    I’d be careful about direct substitution of other opamps in the Rambler – the 386 is a power amp not an opamp. You could probably make it work, but it would need some external circuitry.

    • joe

      Derr. You’re right about the 386, of course. Know anything less noisy? That chip is also used in a lot of micro-amps, like the ones built into mint tins and cigarette packs. It’s always got this timbre that I don’t like much, the quality I referred to in the video as “crumbly.”

      Yeah, I’ve linked to the list of Tim’s projects many times. It is without a doubt one of the most precious resources in the DIY effects realm. The Jawari is pretty cool — but not all that different from the effect you get using these octave pedals on the bridge pickup. But just about everything he’s every designed is worth breadboarding, at least.

  • bear

    The only one of those that didn’t grab me was the Blender. Which is weird because there is kind of a word of mouth worship of those among fans of My Bloody Valentine and Smashing Pumpkins. I could go for any of the other sounds.

    For the Rambler there was something about the sound, especially in non-octave mode, that reminded me of Billy Gibbons. Don’t know how to nuke the noise — you might look at how people try to tame it in other 386 based fuzzes and distortions like the Penny Pedals Finger Print or (IIRC) the Frantone Peach Fuzz.

    Green Ringer as a circuit block to put to better use is smart. R.G. Keen did the same for Visual Sound’s Angry Fuzz, which is a really nice option for an affordable over-the-counter octave fuzz.

    A Super Fuzz supplement would be good for educational purposes — it’s a classic circuit that might as well be listed as an additional band member on some Jesus and Mary Chain albums. A lot of bassists seem to get on well with it, too.

  • joe

    I agree that the Visual Sound stuff is a) really good and b) really fairly priced, and R.G. Keen, of course, is one of the GODS of effects DIY.

    I went back and plugged in my Super Fuzz after realizing I’d omitted it from the round-up. And I was reminded again of why I found it so, well, disappointing the first time I made one (using the excellent BYOC kit). The thing is so legendary, and is supposedly the Live at Leeds fuzz. The non-octave sound has some nice muscle to it, with a tough midrange grind that probably sounds killer with big British amps. But the octave side is extremely scooped and compressed, the kind of distortion that makes your guitar seem to vanish when you whack it on in a band context. And I’d even think twice about calling it an octave effect — it offers a far less clear octave than any of the pedals in my video.

    Well, the Pumpkins always sound more Foxx than Fender Blender to me. Though with the right board EQ, you could probably make the Blender sound a lot more appealing. And while I’m second to none in my admiration for Kevin Shields of My Bloody Valentine, did you ever see that band live? The sound tended not to be the eerie gauziness we love from the records, but exactly what you’d expect from cascading a bunch of fuzz pedals together: huge, loud, impenetrable noise wall. Shields’s studio sound has a lot to do with outboard processing, particularly extreme compression.

  • Derick

    Let’s build one!

  • bear

    The Super Fuzz doesn’t scream octave but it does scream pretty anarchically.

    I saw the MBV tour a few years back where they spared no expense on the live rig. It is different from the albums, but I think the duality comes out of an understanding of the live/studio divide. Y’know how Hendrix was so different in each context? The gauzeiness of eq and compression and some of the weird reverbs was — I think — chasing the psychoacoustics of playing way the F too loud that wouldn’t ordinarily capture in the studio in a way that translates to the album. The sonics of Isn’t Anything weren’t all there and the post-punk influences, and especially those of Sonic Youth and Dinosaur Jr. stuck out more. I think all the time spent building loveless was to get those beautifully weird ear punishing experience to translate.

    To that sort of point, maybe the mid-dipped sounds sound loud at lower volumes in a way that tickles people, Fletcher-Munson effect and all. Kind of like how Metallica isn’t nearly as mid scooped as people think, but it’s hard to tell when they play loud and people play the albums that way, too.

  • bear

    Eek. Last paragraph I forgot to mention that I was talking about the Blender.

  • soggybag

    I built a Green Ringer with the mods posted on the GGG site here:https://www.generalguitargadgets.com/projects/22-octave/131-green-ringer here’s a link to a post and some pictures in my site: https://www.super-freq.com.php5-3.dfw1-1.websitetestlink.com/?p=18

    The filter mod really focuss the octave, I’d say the sound gets almost cartoon like. It cuts the volume so you need to boost the output. You’ll notice the filter is applied before the signal is sent the rectifier to produce the octave. Great effect.

    The milling mod does what’s described but probably not necessary.

    I have a design on the drawing board for a Rambler inspired circuit. I basically asked myself “what would Tim Escobedo do?” And in my mind he would put an LM386 stage in front of the Rambler. I also drew up a version with a transistor rectifier, ala Green Ringer, feeding the two inputs of the LM386.

    You omitted the Shocktave, omnidrive, push me pull you and tripple fuzz. There is also an octave fuzz in the fabled and mysterious, but mostly debunked, Stompbox Cookbook. This had, I think, three on-amp full wave rectifiers in series with phase switches and blend controls. I built this on a bread board once and it didn’t work so well, but hinted at possibility,

  • Digital Larry

    I started thinking about this “sweet spot” phenomenon and how it relates to the harmonic structure of the input signal (your guitar’s output).

    Now the way to pluck your guitar string so as to emphasize odd harmonics is to pluck it near the middle of its length. You’re bending the string into a (very flat) isosceles triangle which then flaps around until the energy dissipates. Picking an open string at the 12th fret generates a very mellow tone. Picking progressively closer to the bridge introduces higher (and even) harmonics.

    If the upper and lower halves of a waveform are not identical (as a sine or any symmetrical wave would be) then when the signal gets rectified, the fundamental is not completely canceled, because the period describing the “repetition” of the waveform is still the full cycle.

    So I believe that the octave “sweet spot” depends both on your fretting hand and picking hand position. It would be in the same place you’d make an artificial octave harmonic. That’s my theory anyway, someone want to give it a try?

    • joe

      That makes total sense, Larry. Also, the “sweet spot” phenomenon is strongest when you play softly with bare fingertips — in other words, with an absolute minimim of bright, percussive transients. The common thread: nixing complex high-end info makes for a stronger octave effect.

  • 3star

    Been experimenting with the Green Ringer and Foxx Tone machine in my “spare time” for a while. Getting some interesting results replacing the tone control on the FTM with a “James/Baxandall” two knob tone stack. Not so successful with the Green Ringer. Any more details on your secret recipe? It has an organ like quality that I am going for.

    • joe

      Well, I’ve found the the trick to getting a good Ringer sound is to precede it with a walloping gain stage. Try placing any clean and low-gain boost pedals you have directly in front of the Ringer, and experiment with different settings. You’ll probably find something that maintains all the cool Ringer harmonic chaos, but with better tracking and a louder sound.

  • Tom Mulhern

    Joe, I just saw this (hey, I don’t get around much). I’ve been a fan of the Foxx Tone Machine since I got one when it came out, back around 1971. I’ve had several, including a Foxx Fuzz/Wah/Volume. For any DIYers, the Tone Machine is dead-easy to make. You can lay it out just like the schematic, although it can be challenging to fit into a small box. I built one using all high-grade parts like 1% resistors, etc., and found that noise was only marginally reduced, leading me to think I should spend the money on better things. Like a Green Ringer.

    • joe

      Hey Ferd! Nice seeing you at NAMM! (Hey folks — this is legendary guitar journalist Tom Mulhern, who everyone calls Ferd.)

      As other have pointed out, the Prescription Electronics Experience Pedal is a clone of the Foxx, as is the Fulltone Ultimate Octave.

  • Joe,

    If your Ampeg Scrambler is too low in volume for you, modify the output stage collector resistor. I have seen it as high as 2.2k.
    This modifies the gain of the output transistor stage, if you don´t want that, you can split the 1k resistor in two and tap off the center.

    I personally found little use for this weirdo effect, my colleague liked it for bass before it went down on him.

    The Foxx is some of the better octave fuzzes. On my web pages I describe a procedure to get more out of it, and most important, fix the dreaded swell section. This makes for some really cool 70ies jazz-rock sounds!

    have fun,


  • Jonathan

    Hi Joe- really great page, very educational. Just wanted to pass on my appreciation.

  • I was just given a 2000-era pedal built by a manufacturer I will leave unnamed (for political reasons) that is rumoured to have been designed by the same fella’ who designed the Foxx Tone Machine. It’s a sick little beast! I haven’t researched the topography, but I’m assuming it’s a silicon fuzz due to it’s extreme fuzz capabilities, but at lower fuzz settings it does clean up well. The octave effect is quite stunning compared to the (very limited amount of) other octave fuzzes I’ve sampled, namely the Fulltone Octafuzz and the Visual Sound Angry Fuzz. Despite my misgivings about it’s manufacturer, I can see this one’s going to be a real recording ace-in-the-hole.

    • joe

      And I believe the FTM rumors are true! It’s a great circuit, and definitely one of the stronger octave effects you’ll find. It’s also the basis for the Fulltone Ultimate Octave.

  • petey twofinger

    Hey Joe , i am not a fan of the lm386 based mini amps . what i have found to much more pleasing is any amp based on tda7052 chip , the tda7052A chip has connections for a volume pot as well . they are twice the power , a lot less distortion , the clean tone is much nicer , everything about these chips is superior to the lm386 , imo .ymmv , pros techs and experts will disagree ( unless they have actually built one then they would never use lm386 again . look into punch amp . i have moved on to using class D amp boards . the sure electronics amp boards on ebay for pennys on the watt are very very nice . i prefer the 25 x 2 7498 based for guitars off 12 volt sla or lap top power supply’s , and the 50 x 2 24 volt for bass guitar . you just cant go wrong , with built in cooling fan / large heat sink but i digress . i do use modelers and such for front ends , eq as well . they have a good off brand board very cheap 25 x 2 for 8 dollars you cant go wrong . dont get me started on octave fuzz , i tame the foxx input caps a bit , adrian belew seemed a bit miffed when i admitted that .

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