Tone Tips

The Birth of a Legend: Build Your Own Electro-Harmonix Axis Fuzz

  • By Nicholas Kula @tonereport
  • July 08, 2016
  • 9 Comments

There has been no more celebrated company in effects history than Electro-Harmonix, and rightfully so. Many of the pedals we use every day are derived—in some way or another—from founder Mike Matthews's tireless dedication to the musician community. Pedals such as the POG, 16 Second Digital Delay, Frequency Analyzer, Memory Man and others were firsts in their field. Mr. Matthews routinely released products with no practical place in the effects storybook. The RTG, or Random Tone Generator does exactly that: it generates a random tone sequence, of which players can vary the speed and glissando. The Panic Button is essentially a white noise generator, outfitted with a cork pad for striking or kicking, allowing guitarists to randomly inject their signal paths with bursts of static. Mike Matthews often released products presumably because he thought them to be cool, not caring if anyone—and I mean that quite literally—bought them or even cared. To that end, we're lucky that such a bastion of innovation exists within a hobby we care about, and it's a big reason why Mike Matthews and Electro-Harmonix are the undisputed heavyweight champs of effects.

Like most companies, Electro-Harmonix comes from humble beginnings. After a stint with IBM, Matthews found himself as the chief builder for Guild, manufacturing the company's Foxey Lady fuzz. This pedal, though it was transparently and shamelessly hitching itself to Jimi, didn't sound like much that the man used, only clouding the tonal pool. With the help of Bob Bell, another technician, Matthews took the Fuzzrite and made it his own. This overhaul of the Fuzzrite featured a few nifty tricks that changed the sound of the Fuzzrite for the better. This new pedal was called the Axis, and it was the first-ever Electro-Harmonix branded pedal—yes, even before the LPB-1. This also marked the first pedal that used 2N5133 transistors, which became Electro-Harmonix's calling card throughout history—some folks say a Big Muff isn't a Big Muff without them.

The Axis circuit is cool for a couple of reasons. For one, it's one of the rarest circuits within a library of hundreds from EHX. Secondly, its Fuzz control is actually a blend between two fuzz configurations; the far left of the control gives players only the first stage, while the far right position cascades the stages. It’s a clever control in a very old circuit, a circuit which still sounds great to this day. And guess what? You’re going to build one.

Disclaimer: Neither I, nor Tone Report Weekly bears any responsibility for any kind of personal or property damage that may occur as a result of the instructions provided herein. Legal mumbo-jumbo aside, we ask that readers be familiar with a soldering iron and its accompanying safety procedures before trying anything listed here. Furthermore, if you fire the pedal up and it does not work, it will need troubleshooting. Assuming the components are not damaged, the pedal will work. I built this very unit according to these instructions and it fired up, first shot, so I know the instructions are correct.

A couple things to note: The original circuit contains two capacitors with odd values that are no longer made and tough to come by—one 50uF and one 4uF. Instead, I decided to replicate these values with parallel capacitors. With resistors, placing two in series allows us to add the values. This is helpful when making a strange resistor value that we may not have. For example, some people may not have 51k resistors on hand, but combining much more common values of 18k and 33k, we can make one. When running resistors in parallel, the formula is quite more difficult than simple addition. It is:

My apologies for the math. That said, if you want to put 18k and 47k in parallel, you plug these values into the calculator. Spoiler alert: it’s 13k, which is a nonconventional value. Why am I telling you this? Well, with capacitors, the formula is the exact opposite. Placing them in parallel adds them together, whereas series placement makes you go through the math. To create the new capacitors of 50uF and 4uF, I used 47uF and 2.2uF in parallel for 49.2uF and two 2.2uF for 4.4uF. Close enough. Would 47uF and 4.7uF (common values) be fine? Probably. I’m just a stickler for accuracy. Journey with me down that path, won’t you? Extra caps only cost a few cents.

On the subject of “extra caps,” the Axis has two capacitors at the end of each stage. They’re relatively small—3.3nF—which gives it its characteristic ‘60s bite. To add some bass back in, simply enlarge the caps. You might prefer to socket the capacitors to experiment. In the interest of mojo preservation, I did not.

Here’s the list of components for the circuit board:

Resistors:
2x 680 ohm
1x 2.2k
2x 22k
3x 47k
2x 470k
Capacitors:
2x 3.3nF (film)
2x 100nF (film)
3x 2.2uF (I used tantalum, you can use regular electrolytics)
1x 47uF (same as above)

Semiconductors:
2x 2N5088 (In the interest of mojo, I used SE4010 from Smallbear. Most 2N5133s are NOT high gain. The SE4010 gain is higher. You can absolutely use 2N5088s though, they are the most widely-available modern equivalent)

Potentiometers:
2x 100kB (linear)
Miscellaneous
1x Veroboard (stripboard), cut and drilled to spec
Wire

Ok, let’s build it!

Step 1: Insert the resistors, bend the leads, and then clip them. Save the leads.

Step 2: Use those leads to form the jumper wires. Bend them ends, then clip them. Discard these. Save one extra lead from step 1.

Step 3: Insert all the capacitors. Normally, we’d separate the film and electrolytics, only because of differentiating sizes. Since I’m using tantalum, I’ve combined them into one step. Bend the leads, clip, then discard.

Step 4: Insert transistors. Normally, we’d use sockets, but these transistors are clearly marked to there’s no confusion. Make sure your transistors are facing the right way by Googling “2N5088 pinout.” The emitter should face the bottom.

Step 5: Insert the wires to the appropriate spots, and solder the potentiometers in.

Ok, now let’s build that enclosure!

1x enclosure of any size, mine is a 1590B
2x knobs of your choosing
2x mono quarter-inch jacks
1x DC power jack
1x 3PDT footswitch
1x LED
1x LED bezel

Step 1: Mount all the hardware inside the enclosure. I turn my jacks like this to shorten the wires. I turn the switch in such a way to feed the negative leg of the LED through its corresponding switch lug.

Step 2: Use the one remaining resistor lead to bridge lugs 4 and 9 on the switch. Solder lug 4, leave lug 9 unsoldered. Here, we will ground the switch to the DC jack and input jack. Run a wire through lugs 2, 3 and 6, and connect the other end to the negative leg of the DC jack (the one dissimilar of the three). Solder the switch lugs, and wire the DC negative to the input jack sleeve lug. Solder the DC jack and wire the input jack sleeve to the output jack sleeve. Solder the Input jack sleeve, leaving the output sleeve unsoldered.

Step 3: Mount the board and potentiometers inside the enclosure. Attach the ground wire from the board to the sleeve lug of the output jack and solder it. Then attach the power wire to the DC jack (run it through BOTH lugs), and attach the power wire to the positive LED leg. Attach the input and output wires from the circuit to the footswitch.

Step 4: Finally, attach the jack tip lugs to the appropriate places on the switch.

Step 5: You’re done! Bask in the glow of your power!

So, what’s it sound like?

 

 

The Axis brings us the tones of ‘60s, pure and simple. A harmonically rich, leaned-out fuzz is the calling card of the Axis. Unlike many fuzzes, the Axis sounds great even with the fuzz control all the way down—a rarity. Because of the gain stage blending, it makes for a versatile fuzz that has many applications, and many more by increasing the output caps for both stages. Try increasing just the second one for a super-versatile fuzz control! Here’s Andy playing my stock version through his Deluxe Reverb.

Until next time, up the irons!

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9 Comments

  1. Barry Ripley

    Your parts list states 2x 2.2uF capacitors but your explanation (I used 47uF and 2.2uF in parallel for 49.2uF and two 2.2uF for 4.4uF) and the diagram shows 3x 2.2uF capacitors… guess I got to order one more.  Cheers!

  2. Iuri

    Hi, i’ve made The pedal and there is still missing The two blue wires that are coming from one of The potentiometers. Where should i connect them?

  3. Iuri

    Hi, Nicolas. I could finish The project in two days and it worked as supposed. I just got some issues with the Jacks but after struggling with it i found The the ones i used was stereo ones but i could solve it right away. I used a piece of a box to isolate The board from The potentiometer and mounted it All in a plástic enclosure. It worked well and sounds very hairy but it is very good fuzz, it even silences itself as a noite gate when The notes are dead. Congrats for The project. It is my first one, and I never had any experiente with electronics before. My only question is about grounding it better. I found that it looses tone when put direct in The floor but I found it working good when I put it about 20cm suspended over another pedal or any kind of support. I found it very trebly but it cuts well through other instruments. Is it possible that I should ground it better in order to keep its basser tones or is it normal that its is a very bright tone pedal?

  4. Nicholas

    @barry Hey, sorry for the confusion. There should be 3 2.2uF caps in the materials list, I’ll fix this.

    @Iuri: I am glad you got it to work! If you’re using a plastic enclosure, the only way to ground it is against the DC jack’s negative terminal. Make sure everything is connected to that point: Both input and output sleeve lugs, the three switch lugs, the board ground, and Volume 1 are all connected. And yes, the tone is naturally very bright. If you’d like to make it a little bassier, make the 3.3nF caps bigger, try 47nF (0.047uF) instead. Cheers!

  5. Zim

    Nicholas,

    I’m in the process of building and I have obviously ordered the wrong resistors.  What wattage should I be looking for?  Thanks for your help.

    Zim

  6. Iuri

    Hi Nicolas, thanks for tour answer. I tryied the pedal a little more and it really cut all the bass frequencies. I’m using a stratocaster with noiseless dimarzio caps that are very medium to bassy sounding, but with the pedal it really cut all the bass from the guitar. I would like to know where do I go to if the 47nF (0.047uF) doesn’t give me the desired bass response, what should be the next componente to use instead? I mean, I really need to get a lot more bass on this one. But again, the pedal has great characteristics.

  7. Iuri

    Still on time, which voltage should I choose this capacitor (47nf)? I didn’t know it would have different voltages for it.

  8. tomhiggins72

    A photo of the bottom of the boards showing connection paths would be invaluable. Maybe you could offer some of those in the future

  9. Sin

    Hi,
    Where do I attach the grounds if I’m totally replacing the dc input with a battery?