Subdecay Prometheus 3 Dual Super Filter B Stock

The Subdecay Prometheus 3 Dual Super Filter B Stock is the discounted, cosmetically blemished version of the Prometheus 3 Dual Super Filter, a filter pedal built around an MS-20-inspired filter design. At its heart are an analog high pass and low pass filter inspired by what Subdecay calls "our favorite 1970s monophonic synthesizer classic," a reference to the Korg MS-20's filter section¹. The B-stock listing sells for $259.00, down from the original $349.00 price².

What B-stock means here

Subdecay describes B-stock as fully functional pedals with superficial blemishes, usually from paint or screen printing issues. The company states that all B-stock items are "warrantied like any other Subdecay pedal," so the B-stock Prometheus 3 carries the same warranty coverage as the regular version².

For a player, the trade is straightforward: the same circuit and controls as the standard Prometheus 3, at a lower price, with cosmetic marks on the enclosure².

A Dual Super Filter inspired by the MS-20

The Prometheus 3's filter design is modeled on the MS-20, the 1970s monophonic synthesizer whose resonant filters became a signature of aggressive, squelchy synth bass and lead sounds. Subdecay implements this as an analog high pass and low pass filter pair, giving the pedal its "Dual Super Filter" name¹².

The pedal is feature-dense beyond the filters themselves. Subdecay's product page lists multiple LFOs, separate envelopes for each filter, tremolo, and savable presets¹. In Subdecay's own buying guide, Brian Marshall notes that "The Prometheus 3 also can get very synthy with its built in octave down envelope," which places it among the more synth-like entries in the company's lineup³.

Presets and 40 editable parameters

The Prometheus 3 offers 40 editable parameters, including 3 LFOs, envelope shapes, overdrive, tremolo, and even the LED color². Editing works through Auto-Set rows: rather than paging through menus, the Auto-Sets send preset values to each parameter in that row. Position 0 recalls the original settings before editing, while position 1 generally sets things to default or "off"¹.

The envelope controls are documented in Subdecay's online user guide, which covers the ENV-CONTROLS section⁴ and the pedal's envelope options, including the envelope select choices that determine how each filter responds to your playing dynamics⁵. The envelope filter bank's parameter knobs control the envelope depth, the filter cutoff frequency, and resonance¹.

How it fits in Subdecay's filter lineup

The Prometheus 3 sits alongside other Subdecay filter pedals, including the Prometheus DLX, the Proteus, the Proteus Auto Filter, the Vocawah, and the earlier Prometheus V2. Compared with those, the Prometheus 3 is the preset-heavy, parameter-deep option, with its 40 editable parameters and 121 factory patches distinguishing it from the simpler entries in the range¹².

Players drawn to its synth character may also want to browse synth pedals more broadly, since the built-in octave down envelope pushes the Prometheus 3 toward synthesizer territory³.

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