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Earthquaker Devices

Earthquaker Devices Erupter Perfect Fuzz

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Music Den Special: $126.65
Earthquaker Devices Erupter Perfect Fuzz
Earthquaker Devices Erupter Perfect Fuzz
Earthquaker Devices Erupter Perfect Fuzz
Earthquaker Devices Erupter Perfect Fuzz
Earthquaker Devices Erupter Perfect Fuzz
Earthquaker Devices Erupter Perfect Fuzz
Earthquaker Devices Erupter Perfect Fuzz
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Erupter Perfect Fuzz

Can we ask you a serious question? When’s the last time you turned up your favorite fuzz pedal to anything but eleven? If there’s one true thing about rock n’ roll, it’s that it sounds best cranked all the way up. But where do we go from here? We go one louder. Enter the Erupter.

The Erupter is the result of over two years’ worth of tone-chasing, tweaking, and experimentation in search of the ultimate classic fuzz tone with a big low end, a biting top end without being too harsh, and just enough output to politely send a tube amp over the top to deliver a well-rounded and defined fuzz tone with just enough pummeling intensity, so you can rock n’ roll all night and still get to bed at a reasonable hour.

It’s the perfect fuzz... just sayin’.


Design Notes

The Erupter™ fuzz started as something I wanted just for myself - the ultimate classic fuzz tone. One with a simple, yet effective control interface and that works anywhere in the signal chain. A fuzz with a big low end, but not too mushy, a biting top end without being too harsh, and just enough output to politely send a tube amp over the top. It must also have excellent wide-range clean up with the guitar’s volume control without losing too much low end. It took a long time and a lot of experimenting to get there but I think I finally nailed it.

A lot of people think this classic circuit is a no-brainer due to its low parts count, but I beg to differ. Since there are so few parts in the circuit, everything makes a difference. That’s why you see so many variations on the market today. You can use the topology, but the sound always varies. I’ve made plenty of designs based on this circuit in the past, but none of them gave me the perfect, overloaded-yet-refined full-force fuzz tone with crushing lows, smooth top end 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 all types and values of capacitors, and basically using every trick I ever learned. What I landed on is exactly the sound I had in my head - the perfect crushing fuzz tone.

I managed to whittle down the controls to the most important one of all, Bias. Why leave out the volume and fuzz controls? Most people leave the volume and fuzz all the way up, at least that’s the way I always do it. This yields the thickest fuzz and the level is slightly above unity to push the full frequency range of the guitar out front when you kick it on. By setting these at maximum and allowing control over the bias, you can freely adjust the character of the fuzz for more tonal variations.

We had a custom center-detent pot made to fit the required resistance for the Erupter. When the Bias control is set at noon you will feel a little click. That means the pedal is perfectly biased to give the best possible fuzz tone. As you turn the Bias counterclockwise (colder) the fuzz lowers in level and becomes more gated. 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 do that? By using transformer based pickup simulation, of course. It’s a cool little trick 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 all the way across the dial!

But what about the parts? What kind of magic is in there? The Erupter uses new production 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 under all extremes. I tried a lot of parts in this circuit during the development. Everything from our usual production 1% 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-rounded and defined fuzz tone with just enough pummeling intensity that I’ve been wishing for.


Tech Specs

List Price: $149.00

Measures: 4.75" x 2.50" x 2.25" with knobs

Current Draw: 9 mA

Input Impedance: 500 KOhm

Output Impedance: <1 KOhm


This device is true bypass and uses electronic relay-based switching. Audio will not pass without power.


This device can be powered by a 9v battery or a standard 9-volt DC power supply with a 2.1mm negative center barrel. We always recommend pedal-specific, transformer-isolated wall-wart power supplies or multiple isolated-output supplies. Pedals will make extra noise if there is ripple or unclean power. Switching-type power supplies, daisy chains and non-pedal specific power supplies do not filter dirty power as well and let through unwanted noise. DO NOT RUN AT HIGHER VOLTAGES!


Delivery & Returns

Shipping Policy

Free Shipping- Most orders $50.00 and over ordered from SHIP FOR FREE, but there are two exceptions: Orders that are being shipped to a location that is not in the lower 48 United States will NOT ship for free. Also items marked as "Oversized" will NOT ship free. Those orders will ship using our Standard Shipping rate.

Standard Shipping- This is the default shipping method for orders shipping to a US state that is not in the lower 48, such as Hawaii or Alaska, Puerto Rico, or an APO/AE order. Whether an order is shipped USPS or UPS is at The Music Den's discretion depending on what the situation may require.

Orders made through will only ship to United States. We are unable to ship internationally.

It may take one to two business days to process an order before it is actually shipped out.

Shipping costs will not be refunded for returns. The buyer must assume all shipping costs when returning an item.

School Servicing- Items will be delivered to the school on our next scheduled weekly visit.

In-Store Pickups- You can choose to pick items up at our Randolph Store. Please call ahead to make sure that your item is at the store before coming to pick it up. Be prepared to present identification and the purchasing credit card during pickup.

Curbside Pickups- Between 10am-5pm, Monday-Friday, you can choose to pick items up at our Randolph Store and have them brought out to you. Please wait for a confirmation email that your item is ready to be picked up. When you arrive you can call the store at 973-927-5800. Be prepared to present identification and the purchasing credit card during pickup.

30 Day Easy Return Guarantee

The Music Den wants you to be fully satisfied with your purchase. The Music Den has a cash back return policy for all online returns 30 days from the date of sale. (Note: This does not apply to Reverb. Please see Reverb for their specific policies. For In-store purchases please refer to your receipt.) Please read the items below carefully to ensure that your Item Return is done correctly.


To return an item purchased online from, you must notify The Music Den within 30 days from the date of the sale to receive an RA#.

All returns must have an RA# (Return Authorization Number). To receive an RA#, Please call 1-800-479-1189 or click here to send us an email. Do not forget to mention your customer number and order number so that we can expedite your request.


All Returns must be received by the Music Den within 10 days of the day you received the RA#.


All shipping costs are the responsibility of the customer and are non-refundable.

The following items cannot be returned: Sheet Music, Books, Reeds, Strings, Harmonicas, Microphones, Clothing, CD's, Videos, DVD's, and Software.

Returned items must be in their original condition and packaging. Returned items not in their original condition will be charged a 15% restocking fee.

Special orders can only be returned at the discretion of a Store Manager with a restocking fee added. All deposits on special orders are non-refundable.

When you ship your item, make sure that your RA# is printed clearly on the outside of the package.


Ship the item to:


The Music Den
1030 Route 10 West
Randolph, NJ 07869


For answers to any questions about our return policy, please call 1-800-479-1189 or click here to send us an email.

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