Pigtronix Philosopher Micro Bass Compressor

The Pigtronix Philosopher Bass Compressor Micro is a compact bass compressor pedal from Pigtronix that combines compression with an overdrive tone the maker describes as mighty¹. Its key control is Blend, which determines the balance of clean-versus-effected tones, and blending some clean signal back in restores the instrument's natural string attack while adding punch and sustain²³. A Grit control modulates the drive tone, moving from a smooth, synth-like fuzz to a doomy wail, and the whole thing fits in a micro enclosure measuring 3.75" x 1.5" x 1.75"²³.

Although it is marketed primarily as a compressor, MusicRadar's review found its most prominent feature is the overdrive side of its character, calling it a "Super-useful, affordable compressor/overdrive"¹. For a bassist, that means one small box can even out dynamics and add sustain while also serving as a source of drive.

What it does to your sound

The pedal is built on the Philosopher's Tone compressor circuit, which Pigtronix brought to bassists with the original Philosopher Bass Compressor in 2013, promising "infinite" sustain and a harmonic distortion "tuned especially for low frequency domination"⁴. The Micro carries that circuit forward in a smaller box².

The compression itself is optical and analog. Bass Gear Magazine's review of the full-size pedal describes "high-quality analog, optical circuitry," and the Micro uses the same approach⁵². Optical compressors read the input signal with a light-dependent element rather than sensing it electrically, which many players find gives a smoother, more musical response.

The BLEND knob is central to how the pedal works on bass: it lets your clean signal be heard in parallel with the compressed signal. As Guitar Interactive Magazine put it when the Micro launched²¹³:

That parallel approach is what keeps a compressed bass from losing its pick or finger attack, a common complaint with fully wet compression².

The controls: sustain, grit, volume and blend

The Micro has four controls. MusicRadar's review walks through what each one does¹:

MusicRadar found the Sustain control "does a great job of varying the effect threshold and limiting (or delimiting) the peaks and spikes caused by your playing, while keeping the bottom end intact"¹. The Grit control earned particular praise: the reviewer found you can modulate the drive tone effortlessly, "moving from a smooth, synth-like fuzz to a doomy wail"¹. Blend is described as the key control, since it governs how much of your untouched tone sits under the compressed and driven signal¹.

The full-size Philosopher Bass Compressor handled grit differently, with a toggle switch for harmonic grind rather than a knob, alongside volume, compression and sustain controls⁶³. Bass Musician Magazine's Ty Campbell described that switch as giving "a subtle distortion"⁶.

Power: 9V doubled to 18V rails

The Micro runs on standard 9VDC external power, but an internal voltage-doubling circuit provides 18VDC power rails, which Pigtronix describes as delivering superior performance². MusicRadar's review frames the benefit in practical terms: "there's an internal voltage-doubling circuit that gives you and your active bass 18 volts of DC"¹. Higher internal rail voltages give a circuit more headroom, which matters for the hot output of active basses.

The full-size pedal took a different route: it accepts 9 to 18VDC, and shipped with an 18VDC 300mA supply included⁷³. Pedal of the Day's reviewer noted it "can run on either 9v or 18v for more headroom"³. With the Micro, you get the 18V rails from an ordinary 9V supply instead.

From the Philosopher's Tone to the Micro

The circuit's family tree runs through several steps. Pigtronix's original Philosopher's Tone was the company's flagship compressor. In 2016 the company announced the Philosopher's Tone Micro, a miniature, 1590A-sized version with true-bypass switching, volume and sustain controls⁸⁷. Gearnews reported it as "a new miniature version of their popular compressor pedal"⁹.

Independent technical analysis by Aion FX, which traced the Philosopher's Tone Micro circuit, found two changes that matter to bass players: a charge pump was added so the pedal could run on a standard 9V adapter, and an adjacent coupling capacitor was raised from 560n to 1uF. As Aion FX explains, "The capacitor increase would cause it to pass more low frequencies to the compressor portion, which makes the circuit more suitable for bass guitar"⁷. That low-frequency pass-through is the technical basis for the bass-specific versions.

The Philosopher Bass Compressor itself debuted at Winter NAMM 2013, alongside the Bass FAT Drive and the Bass Envelope Phaser, as Pigtronix's first bass effects pedals⁴. The Philosopher Bass Compressor Micro followed in June 2018, compressing the bass compressor into the micro format².

What reviewers said

Reviews of the family have been positive across the board. Pedal of the Day's Jay Y called the full-size Philosopher Bass Compressor "a compressor specifically tuned to the lower frequencies of a bass that is quiet, easy to use, and affordable," with "a great compression circuit that responds very well to the lower frequencies of a bass signal"³¹⁰. He reported keeping one on his board for about a year¹⁰.

Bass Musician Magazine's Ty Campbell reviewed the full-size pedal after using it on a small club gig and an outdoor festival, noting its grit function and 9V/18V power options⁶³. Pedal of the Day's reviewer also uses the pedal at churches, mostly with passive basses³.

On the Micro itself, MusicRadar's verdict was concise:

The same review noted the true-bypass switching "ensures that the unit doesn't muddy up your tone when you're going straight through it," and that the pedal "doesn't cost a crippling amount"¹.

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