The PastFX PolyChorus is a compact analog multi-modulator pedal that recreates the 1977 Electro-Harmonix Echoflanger, the 1979 Polyflange and the circa-1981 Polychorus circuit, using an MN3007 bucket-brigade device (BBD) chip. In one box it covers double tracking, slapback delay, chorus, vibrato, flanging and filter matrix effects, and Guitar Pedal X describes it as shrinking the original down to less than a third of its size while maintaining the same classic soundstage, fidelity and dynamics1.
From the Echoflanger and Polyflange to the Polychorus
PastFX followed the same release cycle as Electro-Harmonix did originally: the company initially released its Echoflanger version first, and then the later and current PolyChorus edition. The Polychorus followed the Echoflanger by a week, in November 20252. Both pedals use vintage NOS Panasonic MN3007 chips; the teal Polychorus variant with black inset carries two of them onboard2.
The original Electro-Harmonix Stereo Polychorus, an analog chorus, flanger and slapback echo pedal, was discontinued in 20113. Barry Rudolph's independent review of that unit noted a Feedback control used in the chorus and flange modes, and put its retail price at $2754.
PastFX as a maker specializes in compact modulation pedals covering choruses, phasers and flangers, with 11 models in its range: 4 choruses, 3 phasers and 4 flangers5.
Controls and modes
The PolyChorus is a 4-mode pedal. Its external controls and mode selector1:
| Control | Function |
|---|---|
| Rate | Modulation rate |
| Modulation Width | Depth of the modulation |
| Tune | Delay time |
| Feedback | Feedback amount |
| Blend | Wet/dry mix |
| Mode | Double Track / Slapback Delay, Chorus / Vibrato, Flange, FilterMatrix |
A dual LED system, introduced by PastFX's Verlie, shows which family of effects is engaged: the blue LED lights for Double Track and FilterMatrix, and the green LED lights for Chorus/Vibrato and Flanger1.
What reviewers said
Guitar Pedal X's Stefan Karlsson reviewed the PolyChorus in April 2026 and gave it a strong verdict:
"This is a fantastic multi-modulator which goes for $310 on thePastFX Reverb.com store - really well worth it."1
Stefan Karlsson, Guitar Pedal X1
The Polychorus and Nirvana
The original Polychorus has a documented place in grunge history: Guitar Pedal X notes that it was used all over Nirvana's third and final album In Utero, and particularly on the track "Radio Friendly Unit Shifter"1.
Questions
What is the PastFX PolyChorus based on?
It recreates the 1977 Electro-Harmonix Echoflanger, the 1979 Polyflange and the circa-1981 Polychorus circuit, in a compact enclosure that Guitar Pedal X describes as less than a third of the original's size while keeping the same soundstage, fidelity and dynamics. PastFX released its Echoflanger version first in November 2025, followed a week later by the Polychorus edition.
Is the PastFX PolyChorus analog?
Yes. Guitar Pedal X describes it as an analog multi-modulator built around a Panasonic MN3007 bucket-brigade device chip, the same kind of chip used in the vintage Electro-Harmonix units it is based on. The original Electro-Harmonix Stereo Polychorus was also an analog chorus, flanger and slapback echo pedal, discontinued in 2011.
What BBD chip does the PolyChorus use?
The PolyChorus uses an MN3007 bucket-brigade device chip. The teal PastFX Polychorus variant with black inset carries two vintage NOS Panasonic MN3007 chips onboard, according to Guitar Pedal X.
What do the blue and green LEDs mean on the PolyChorus?
PastFX designer Verlie introduced a dual LED system on the PolyChorus. The blue LED lights for Double Track and FilterMatrix modes, and the green LED lights for Chorus/Vibrato and Flanger modes, so you can see at a glance which family of effects is engaged.
How much does the PastFX PolyChorus cost?
Guitar Pedal X's April 2026 review put the PolyChorus at $310 on PastFX's Reverb.com store. As of October 9th, 2026, the price was listed as £239. PastFX's standard editions of its modulation pedals have typically sat at $210 USD.
Which Nirvana album used the original Polychorus?
According to Guitar Pedal X, the Polychorus was used all over Nirvana's third and final album In Utero, and particularly on the track 'Radio Friendly Unit Shifter'.
Sources (5)
- Guitar Pedal X, Guitar Pedal X, 2026-04-07
- Guitar Pedal X, Guitar Pedal X, 2026-09-21
- Stereo Polychorus, Electro-Harmonix (ehx.com)
- Stereo Polychorus from Electro-Harmonix, barryrudolph.com, 2021
- Guitar Pedal X, Guitar Pedal X, 2024-11-14
