The Wilson Effects Dirty Beaver is a hand-built fuzz pedal made in Guilford, Indiana, that recreates the Ram's Head Big Muff, the early to mid 1970s version of the Big Muff Pi prized for its thick, aggressive sustain. Wilson describes it as built "to capture the legendary Ram's Head Big Muff tones while offering additional options to fine-tune" the sound, and the additional options are the pedal's main departure from the original: toggle switches that swap diodes in and out of the circuit, changing the gain structure and character of the fuzz12.
The Ram's Head circuit
The Ram's Head is the Big Muff variant produced in the early to mid 1970s, and it has a strong reputation among fuzz players. Kit Rae's Big Muff history site describes the Electro-Harmonix reissue of this version as "thick and dirty sounding" and accurate to "the signature tone of many of those early to mid 1970s Ram's Head" pedals2. Premier Guitar, reviewing the reissue, noted "the handsome reproduction of original Ram's Head graphics on the circuit board and enclosure"4, and in another review called the original Ram's Head Big Muffs "among the most aggressive-sounding Muffs ever produced"5.
Wilson Effects leans into that heritage with what the maker calls a vintage-inspired build: carbon composition resistors mounted on a unique red spiral circuit board, chosen "for true-to-era" construction1. The enclosure carries bold graphics the maker describes as vintage tone with modern style1.
Controls and the diode toggles
The Dirty Beaver keeps the Big Muff layout and adds the toggles that set it apart31:
- Standard fuzz controls for volume, tone and sustain, in the Big Muff manner1
- Diode toggle switches that "modify the circuit by swapping diodes in and out, adjusting the gain structure and character of the fuzz"1
On the maker's product page, Wilson Effects puts it this way: "We've added toggle switches that mod the circuit by swapping diodes in and out of the circuit"3. For a player, that means one pedal can cover several shades of Ram's Head-style fuzz, from the stock character to altered clipping voicings, without changing pedals.
Power, bypass and practicalities
The Dirty Beaver runs on a 9VDC battery or a 2.1mm center-negative power supply, the standard connector for most pedalboard supplies1. It is true bypass, which Wilson Effects says "preserves your signal when the pedal is off"1.
Wilson Effects ships orders via USPS Priority Mail3. Returns are accepted within 7 days of receiving a new pedal, but shipping costs are not refunded and return shipping is the customer's responsibility3.
The pedal carries a one-year warranty covering parts and labor1.
Wilson Effects and its fuzz line
Wilson Effects is a small US builder whose catalog is heavy on fuzz. The company released the NotRite, a fuzz based on the Fuzzrite circuit, in March 2020, and revamped its pedal line in 2021, including the Fuzz MKIII. Other fuzzes in the line include the Mordant, the Octave Fuzz and the No Face NPN. For more on the effect type itself, see the site's guide to Fuzz Pedals.
Demo
Wilson Effects publishes its own demo of the Dirty Beaver on its site, titled "Dirty Beaver Demo | Wilson Effects"6. The demo page also lists the pedal's price as $185.00 USD, so the video may be worth watching on the maker's page directly6.
Videos
ProGuitarShopDemos
Wilson Effects
Brett Kingman
Questions
Which Big Muff is the Wilson Dirty Beaver based on?
Wilson Effects built the Dirty Beaver to capture the Ram's Head Big Muff, the early to mid 1970s version of the Big Muff Pi that Premier Guitar has described as among the most aggressive-sounding Muffs ever produced. The pedal uses carbon composition resistors on a red spiral circuit board for a true-to-era build, and adds toggle switches that swap diodes in and out of the circuit to adjust the gain structure and character of the fuzz.
Is the Wilson Dirty Beaver true bypass?
Yes. Wilson Effects lists the Dirty Beaver as true bypass, which preserves your signal when the pedal is off.
Does the Wilson Dirty Beaver run on a battery?
Yes. According to Wilson Effects, the Dirty Beaver runs on a 9VDC battery or a 2.1mm center-negative power supply, so it can be used either way.
What kind of power supply does the Dirty Beaver need?
The Dirty Beaver needs a 9VDC, 2.1mm center-negative power supply, the standard connector used by most pedalboard power supplies. It can also run on a 9VDC battery.
Where is the Wilson Dirty Beaver made?
Wilson Effects builds the Dirty Beaver by hand in Guilford, Indiana, USA, using premium components, according to the maker's product page.
What warranty comes with the Dirty Beaver?
Wilson Effects includes a one-year warranty covering parts and labor with the Dirty Beaver. The maker also accepts returns within 7 days of receiving a new pedal, though shipping costs are not refunded and return shipping is the customer's responsibility.
Sources (6)
- Dirty Beaver, Wilson Effects
- The Big Muff History of All Versions Part 1, Kit Rae (kitrae.net), 2024-04
- Dirty Beaver, Wilson Effects
- Electro-Harmonix Ram’s Head Big Muff Review, Premier Guitar, 2020-02-03
- Maxon FWA10 Fuzz Elements Water Review, Premier Guitar, 2014-09-06
- Dirty Beaver Demo, Wilson Effects, 2026-10-19
