The GUP Tech RCKT Shadow Phzr is a dual channel phaser pedal with a vibrato mode, made by the Canadian builder GUP Tech. The maker describes it as an evolution of the Electro-Harmonix Small Stone, an OTA phaser with a lot of mods, and as based on the late Blackout Effectors Whetstone Phaser. It does not quite get the exact sounds of the Whetstone, the maker says, especially in the vibrato mode.1
Both the standard RCKT Shadow Phzr and the Douche Edition were listed as sold out on the maker's product pages as of 26 October 2026.12
What it does
As a phaser, the RCKT Shadow Phzr sweeps filters through your signal for the classic whooshing phase effect, but it does so with two channels rather than one. The maker says it carries two storable Rate settings, foot switchable with the left footswitch, so you can flip between two speeds mid-song without bending down to turn a knob. Alongside the phaser setting there is a vibrato mode, which takes the modulation deep enough that the pitch wobbles on its own.1
The pedal also has a volume control, which the maker says gives a good boost, enough to push the pedal's output above unity if you want it.1
Circuit lineage
GUP Tech is explicit about where the design comes from:
"It's an evolution of the EHX small stone, an OTA phaser with a lot of mods."
GUP Tech product page1
The Small Stone, first built by Electro-Harmonix, is an OTA (operational transconductance amplifier) phaser, a circuit approach that uses OTA chips rather than the more common optical or FET methods to sweep the phase stages. The RCKT Shadow Phzr takes that design as its starting point and layers modifications on top, and the maker names the late Blackout Effectors Whetstone Phaser as the pedal it is based on. GUP Tech is careful to say it does not quite get the exact sounds of the Whetstone, especially in the vibrato mode.1
Douche Edition
The Douche Edition is a variant of the same pedal, sold separately as the RCKT Shadow Phzr - Douche Edition. It carries the same description on the maker's page: a dual channel phaser, an evolution of the EHX Small Stone based on the Whetstone, with the same 9VDC center negative power requirement and 5mA current draw. It was also listed as sold out.2
Colors and availability
The maker's product page lists color options for the RCKT Shadow Phzr including Green, Seafoam, Blue, Orange and Purple.1
The page showed a sale price of £109.00 GBP (listed in British pounds by the maker, as stated) and a status of sold out, based on 3 reviews with 100% positive on the maker's site.1
Videos
GUPtech
GUPtech
Sources (2)
- RCKT Shadow Phzr, guptech.ca
- RCKT Shadow Phzr, guptech.ca
