Electro-Harmonix Bass Big Muff Pi 2

The Electro-Harmonix Bass Big Muff Pi 2 is a dual op-amp bass fuzz pedal from Electro-Harmonix, released in 2026¹. It fuses the Big Muff's long history as a favorite fuzz among bassists with a rare "Op-Amp" circuit from the 1970s that was almost forgotten, a design resurrected in collaboration with Josh Scott of JHS Pedals¹². Electro-Harmonix describes it as carrying the signature midrange grind of the original with the flexible EQ and virtually endless sustain expected in any Big Muff, optimized for bass players without sacrificing low-end flavor¹.

Where the earlier Bass Big Muff Pi offered a binary dry toggle, the Pi 2 gives bassists a full wet/dry BLEND knob plus a BASS BOOST switch, two controls the regular three-knob Big Muff 2 does not have³. Gearnews summed up its purpose as built specifically for bass players who want a heavy, grit-filled fuzz sound without losing the deep, low-end punch of their instrument².

Controls and circuit

The circuit is a unique Big Muff Pi design employing 2 dual op-amps, the same style of circuit as the recent Big Muff 2 but tuned for bass guitar¹². Guitar.com traces it to an early, unrealised variant of the dual-op-amp Big Muff Pi developed with Josh Scott and issued by EHX³, and gearnews calls it a newly rediscovered "lost circuit"².

Five controls shape the sound:

The BLEND knob is the significant change from earlier versions. Premier Guitar describes it as setting the overall wet/dry mix to dial in the perfect balance of fuzzy chaos and solid fundamentals from your clean tone⁵, and Guitar.com notes the clean blend goes from no clean blend at all to fully clean, still boosted by the pedal's volume control to properly compete with the fuzz signal³. The BASS BOOST switch adds even more low end for booming bass tone even at higher TONE settings⁵.

The footswitch uses latching and momentary action: press and hold for more than half a second for a momentary burst of fuzz, and the momentary action may be disabled if you prefer plain latching switching¹. Guitar World's reviewer noted this is a metal plunger footswitch which, for the first time in Muff history, is able to trigger momentarily should you only require a short burst of fuzz⁶. The status LED lights when the effect is engaged and is off in bypass¹.

Deluxe Bass Big Muff Pi 2

In May 2026 Electro-Harmonix released the Deluxe Bass Big Muff Pi 2, which upgrades the dual op-amp Bass Big Muff 2 with pro features⁷⁸. It takes the once lost dual op-amp Big Muff 2 design to the max with flexible tone shaping and pro upgrade features, according to the maker⁸.

The Deluxe keeps VOL, TONE and SUSTAIN controls plus a BLEND knob that mixes dry and distorted signals, and adds several features the standard pedal does not have⁹⁸:

• A GATE knob controlling the input amplitude needed to open the noise gate; turned all the way down, the noise gate is disabled⁸
• An INPUT toggle engaging 10dB of attenuation for basses with active pickups, or 0dB for none⁸
• A footswitchable CROSSOVER that splits the signal in two, applying a high-pass filter to the signal feeding the fuzz circuit and a low-pass filter to the dry signal⁸⁷
• HPF and LPF controls for those two filters⁸
• An XLR DI OUTPUT, a low impedance output of the effected signal for a mixing console or recording equipment⁸⁷
• A DIRECT OUT, a buffered output of the clean, original signal⁸⁷

The main footswitch engages or bypasses the effect, with a red LED when engaged, and a second soft footswitch turns the Crossover circuit on or off, with a green LED when active; both support momentary action on a hold of more than half a second⁸. The Deluxe is analog, uses buffered bypass, and measures 5.75 x 4.75 x 2.5 inches⁸. Unlike the standard pedal, it has no battery compartment¹⁰.

Power and connections

The standard Bass Big Muff Pi 2 runs on a 9V battery, which is included, or on an optional 9.6VDC-200mA power adapter, which is not included¹. An optional 9VDC, center-negative power supply may be connected to the power jack to provide power without a battery, and the manual warns not to exceed 12VDC at the power jack¹. The maker's specifications table lists a current draw of 20mA¹, while the power jack section of the same page states 25mA at 9VDC on a center-negative plug¹; a power supply rated above 25mA covers both figures.

Connections are simple: a quarter-inch instrument input on the right side of the pedal and a quarter-inch audio output on the left¹⁶. The audio path is mono¹. Guitar World measured the pedal at 70 x 114 x 53 mm and 340g, housed in a solid metal enclosure in a dark metallic green finish with four solid-feeling pots and a metal mini-switch⁶.

The Deluxe draws 45mA at 9.0VDC, center-negative, and ships with a 9.6VDC-200mA power adapter included⁸. Its input impedance is 2.2MΩ and its main output and DIRECT OUT impedance is 550Ω⁸.

Price

The Bass Big Muff Pi 2 carries a US street price of $122.00¹⁴. Guitar World lists it at $122⁶, and Guitar.com also lists it at $122³.

The Deluxe Bass Big Muff Pi 2 carries a list price of $188.20⁸¹⁰¹¹. A later affiliate listing showed it at $169.00¹², with a Nano Bass Big Muff Pi 2 listed at $101.00¹²⁹¹³.

What reviewers said

Guitar.com reviewed the pedal in July 2026 and rated it 9 out of 10³¹. The reviewer found the Big Muff 2's voicing works great on bass, that the clean blend knob and bass-boost toggle keep things rumbling along nicely, and that it is affordable with an easy-to-use form factor, great on guitar too, if a little more unconventionally so³. Testing it through an affordable MarkBass head set dead clean and a 1x15" cab, the reviewer found it provided a thunderous amount of low-end, even with the distortion maxed out³.

The same review flagged one limitation: it is hard to stay subtle with the tones on offer, and fans of a tasteful smattering of overdrive will find the fuzz side quickly getting too distorted³. On the board of a bassist in a doom metal band, the reviewer concluded it more than does the job³, and on guitar with a light overdrive in front it makes a unique parallel drive sound if the amp has headroom, or an equally unique over-fuzzed tone if not³.

Guitar World's review gave build quality four stars out of five, describing a well-considered item¹⁴, and Steve Cook reviewed the pedal for Premier Guitar¹⁴.

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