Ultimate Fuzz Tone
Can we ask you a serious question? When was the last time you turned your favorite fuzz pedal up to anything other than eleven? If there's one thing true about rock n' roll, it's that it sounds better when loud. But where do we go from here? We are going one stronger. Enter the Eruptor.
The Erupter is the result of over two years of sound research, tuning and experimentation in search of the ultimate classic fuzz sound with big bass, biting highs without being too harsh and just enough output to send politely a tube amp on top to deliver a well-balanced and defined fuzz sound with just enough punch, so you can rock n' roll all night and still go to bed at a reasonable hour.
It's the perfect fuzz... for information purposes ;-).
Bias: This control has a center detent for the “perfect” fuzz setting. In the center position, the sound will be big and round with a slight increase in volume and excellent sustain. When you turn it counterclockwise, it becomes more stuck with lower output. By turning it clockwise, it becomes stronger and more refined.
Design Notes
The Erupter™ fuzz started as something I wanted just for myself - the ultimate classic fuzz sound. One with a simple but effective control interface and one that works anywhere in the signal chain. A fuzz with a big low end, but not too smear, a biting high end without being too harsh, and just enough output to politely send a tube amp over the top. It should also have excellent wide-range cleaning with the guitar's volume control without losing too much low end. It took a long time and a lot of experimentation to get to this point, but I think I finally succeeded.
Many people think this classic circuit is a no-brainer due to its low parts count, but I disagree. Since there are so few parts in the circuit, everything makes a difference. This is why you see so many variations in the market today. You can use topology, but the sound still varies. I've done a lot of designs based on this circuit in the past, but none of them gave me the perfect, overdriven but refined fuzz sound, with crushing bass, smooth highs, and an input that is responsive through the full range of the guitars volume control without losing too much low end in the process. Until now!
I spent almost two years swapping transistors, measuring resistors, adding controls, removing controls, trying every type and value of capacitor, and basically using every trick that I never learned. What I landed on was exactly the sound I had in mind - the perfect crushing fuzz sound.
I managed to narrow down the controls to the most important of all, Bias. Why leave out the volume and fuzz controls? Most people leave the volume and fuzz at maximum, at least that's how I always do it. This gives the thickest fuzz and the level is slightly above unity to push the entire frequency range of the guitar forward when you press it. By setting them to maximum and allowing bias control, you can freely adjust the character of the fuzz for more tonal variations.
We had a custom center trigger pot made to accommodate the resistance required for the Erupter. When the Bias control is set to 12 o'clock, you will feel a small click. This means the pedal is perfectly biased to give the best fuzz sound possible. As you turn the Bias counterclockwise (colder), the level of the fuzz decreases and becomes more blocked. As you turn the Bias clockwise (hotter), the fuzz becomes cleaner and more refined and the output level increases.
The Erupter also has a buffered front end to give the best possible input signal with stronger highs, tighter lows, and allows it to be used before or after any other effects (even a wah pedal) without the usual problems associated with this circuit. What!? How's it going ? Using a transformer-based pickup simulation, of course. This is a cool little tip I learned from an article written by Jack Orman almost 15 years ago. These two features allow greater use of the guitar's volume control to clean up the fuzz. Try it, you'll be amazed at the amount of tones you can get throughout the dial!
But what about the parts? What kind of magic is there in this? The Erupter uses new 5% ½ watt carbon composition resistors, metallized polyester film capacitors, Sprague and BC electrolytic capacitors and NOS, hand matched low gain silicon transistors for temperature stability and predictable operation in all extremes. I tried a lot of parts in this circuit during development. Everything from our usual 1% production metal film resistors and caps to expensive NOS paper in oil capacitors. I tried every rare germanium transistor I had and countless different silicon transistors. What I landed on gave me the well-balanced and defined fuzz sound with just enough punch intensity that I wanted.