The Blackout Effectors Whetstone Phaser was an analog phaser pedal built around OTA chips, the same approach as the Electro-Harmonix Small Stone it was based on. Aion FX describes it as a Small Stone with several modifications, including additional controls and switches and an output gain boost, and notes that it replaced the obsolete CA3094 OTA with the NE5517/LM13700, essentially a dual version of the chip1. Blackout's own description of the range of sounds, quoted on the Guitar FX Layouts page, was wide: "From classic and not-so-classic sounds, subtle and over-the-top phase tones, mellow through seasick pitch vibrato, ringmod, glitchy octave effects, and outright strange phased/autowah/tremolo hybrid sounds you won't find anywhere else"2.
Release and discontinuation
The Whetstone was originally released in 2009 and was discontinued when Blackout closed their doors in 2018, according to Aion FX1. A current product page refers to it as "the late Blackout Effectors Whetstone Phaser"3, which lines up with that end of production.
The Whetstone has been out of production since 2018. Any unit on sale now is a used or leftover example, not new stock.
Circuit and sound
The pedal is an analog, OTA-based phaser2. OTA stands for operational transconductance amplifier, the chip type that gives the Small Stone family its character. Guitar FX Layouts describes the combination as "the vintage sound of an analog OTA-based phaser melded with contemporary parameters"2.
Beyond the Small Stone starting point, Aion FX records a set of changes Blackout made to the circuit1:
- Additional controls and switches beyond the original layout
- An output gain boost
- Replacement of the obsolete CA3094 OTA with the NE5517/LM13700, essentially a dual version of the chip
Fix mode
The Whetstone's FIX setting kills the LFO completely, per the Guitar FX Layouts discussion, which stops the automatic sweep and leaves the phase position set by hand2. Aion FX flags a quirk in that mode: the lower half of the rotation produces audible high-pitched oscillation, and the actual swept-phase frequency changes happen only around the last 25% of the knob's travel1.
DIY layout
A stripboard layout for the Whetstone was published on Guitar FX Layouts in September 2018, with an unverified schematic link to freestompboxes.org2. Builders on that page reported fitting the circuit in a 1590PP enclosure, about double the height of a standard 1590 enclosure2.
| Build detail | Detail |
|---|---|
| Layout type | Stripboard2 |
| Published | September 20182 |
| Schematic | Unverified link to freestompboxes.org2 |
| Enclosure used by builders | 1590PP, about double the height of a standard 15902 |
The layout notes also cover the rotary switch used in the circuit: only pins A, 1, 2 and 3 of the 3P4T rotary are used, with the other pins unconnected2.
Videos
ProGuitarShopDemos
ProGuitarShopDemos
kismet78
Questions
Is the Blackout Effectors Whetstone Phaser still made?
No. Aion FX describes the Whetstone as discontinued when Blackout Effectors closed their doors in 2018, and a current product page refers to it as the late Blackout Effectors Whetstone Phaser. The pedal was originally released in 2009, so any unit sold today comes from the used market rather than new production.
What is the Whetstone Phaser based on?
According to Aion FX, the Whetstone was based on the Electro-Harmonix Small Stone, a classic OTA phaser, but with several modifications. These included additional controls and switches, an output gain boost, and the replacement of the obsolete CA3094 OTA chip with the NE5517/LM13700, essentially a dual version of the chip.
What does Fix mode do on the Whetstone?
On the Guitar FX Layouts page, the FIX setting is described as killing the LFO completely, which stops the automatic sweep and leaves the phase position under manual control. Aion FX also notes a quirk: the lower half of the relevant control's rotation produces audible high-pitched oscillation, with swept-phase frequency changes limited to around the last 25% of the knob's travel.
Is the Whetstone Phaser analog?
Yes. Guitar FX Layouts describes it as the vintage sound of an analog OTA-based phaser melded with contemporary parameters. OTA stands for operational transconductance amplifier, the chip type at the heart of the Small Stone circuit it was based on.
Can I build a Whetstone Phaser myself?
A DIY stripboard layout was published on Guitar FX Layouts in September 2018, with an unverified schematic link to freestompboxes.org. Builders there reported fitting the circuit in a 1590PP enclosure, which is about double the height of a standard 1590 enclosure, so plan for a roomy box.
Sources (3)
- Redshift Deluxe Phaser / Blackout Whetstone, Aion FX, 2020-06-19
- Guitar FX Layouts: Blackout Effectors Whetstone Phaser, Guitar FX Layouts (tagboardeffects.blogspot.com), 2018-10-27
- Lab Series #17, guptech.ca