ThorpyFX Pulse Doppler Phase Shifter

The ThorpyFX Pulse Doppler is an analog phaser pedal with a vibrato mode, and it can also produce tremolo sounds. ThorpyFX positions it as a MKII version of the Doppleganger, the phaser/vibrato pedal that Dan Coggins designed for Lovetone in the 1990s¹. It was the first design ThorpyFX released after Coggins became a full-time member of the team¹.

Announced in May 2021, the Pulse Doppler was created by Adrian Thorpe's ThorpyFX with Coggins on board, the man behind the boutique Lovetone effects of the '90s². Delicious Audio described it as an analog device that "can deliver anything from phaser to vibrato to tremolo"³.

What it is and what it does

A phaser splits your signal and shifts the phase of one path, then recombines it so notches sweep through the frequency spectrum. The Pulse Doppler is a four-stage, two-notch phaser, according to MusicRadar's review⁵. Because the wet (phase-shifted) and dry signals are available on separate outputs, you can run it into two amps for stereo, or use the dry output on its own.

Beyond straight phasing, the Vib/Phase footswitch drops the dry signal entirely for a vibrato sound, where the pitch wobbles instead of the tone sweeping. Delicious Audio's write-up also covers tremolo territory, where the volume pulses rather than the pitch³.

Controls, switches and footswitches

The pedal carries five rotary knobs: Depth, Rate, Blend, Enhance and Manual¹. Two toggle switches select between the five operating modes, and two footswitches handle bypass and the phaser/vibrato changeover².

The five modes are selected via the two toggle switches and include Bi-Directional (figure of 8) and Dual Phasing, alongside a Normal mode that is a simple phaser²³. A further three-way switch, covered in Guitar World's review, offers alternate tonalities: with the straight and phase-shifted signals in phase you get the fullest sound, while inverted phase adds an element of hollowness. The middle Pulse setting removes low-frequency content from the phased signal, acting as a modulated high-pass filter for a leaner sound⁴.

The two footswitches are labeled On/Off and Vib/Phase². Guitar World's reviewer Trevor Curwen singled out the Vib/Phase footswitch as a reason to buy the pedal, since it lets you jump between phaser and vibrato sounds mid-performance⁴.

Stereo outputs

The Pulse Doppler has both dry and wet outputs¹. MusicRadar's review explains the practical use: run it in mono with a single output, or in stereo, sending the phase-shifted signal to one amp and a dry signal to another⁵. Gearnews noted the stereo outputs make it "a lot of fun in the studio and, of course, in stere" setups².

ThorpyFX also offers the pedal with optional Barefoot Button footswitch extensions, with colors available on request¹.

Lineage: the Lovetone Doppelganger, MKII

The Pulse Doppler's circuit traces back to the Lovetone Doppelganger, a four-stage optical phaser first released in 1995⁶. The original covered phaser and vibrato sounds and has become a sought-after vintage pedal. Guitar World's review notes that Dan Coggins "was behind Lovetone's much sought-after Doppelganger phaser/vibrato from the 1990s, which surely donated some of its" character to the Pulse Doppler⁴.

Gearnews called the original a legendary pedal and framed the Pulse Doppler as the MKII: "These two electronic circuit wizards have taken the original '90s Lovetone Doppelganger to create a MKII version"². Guitar World's news piece described it simply as an updated version of the Doppleganger⁷.

On value, Gearnews's verdict was direct:

The same outlet also described the sound in its launch coverage: "Just take a listen to the demos below and hear how sumptuous and chewy this pedal sounds"². Guitar Pedal X later listed the Pulse Doppler Phaser among ThorpyFX pedals released in black editions, alongside the Fallout Cloud fuzz and Camoflange flanger⁸.

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