The Tech 21 Killer Wail is a wah pedal from Tech 21 that aims to keep what players like about vintage wahs while fixing what breaks on them. Tech 21 describes it as preserving "the original tonal integrity of vintage wahs" while overcoming "familiar shortcomings, such as excessive noise and unreliable mechanical parts"1. The biggest mechanical change is the sweep: instead of a potentiometer, the Killer Wail v2 uses light sensor technology, so there are no clunky pops, no scratching sounds, and no pot to wear out and replace1.
The story starts with the original Killer Wail, which Tech 21 described as "considerably warmer and more 'musical' than conventional wahs," built to overcome the classic wah's faults while preserving the original circuit design2. In late 2024 Tech 21 introduced two Killer Wail Limited Edition pedals, sold directly through its Private Stock division on Reverb. Given their success, the company moved to full-scale production with three pedals: the Killer Wail v2, the Richie Kotzen Signature RK Killer Wail, and the Killer Blue Wail for bass3.
A wah that keeps the classic circuit and cuts the noise
The design idea behind the Killer Wail is straightforward: keep the tone of a vintage wah, replace the parts that cause trouble. Tech 21 says the Killer Wails preserve the tonal integrity of vintage wahs while overcoming excessive noise and unreliable mechanical parts1. Premier Guitar reported the same framing when the production versions were announced3.
Two design choices do most of the work:
- Light sensor sweep. The treadle position is read optically rather than through a pot, which eliminates the scratching and popping that a worn pot produces, and removes the one part that most often needs replacing on a vintage wah1.
- A specially-designed filter. Rather than a simple band-pass or low-pass filter, the Killer Wail uses a filter that changes both frequency and Q as you sweep1.
The original Killer Wail took a similar approach with its humbucking inductor: a custom wound and potted inductor coil that cancels noise and reduces microphonics while reproducing the saturation and harmonics of vintage wahs2. Its bypass switch also used an extra pole to remove the circuit load, which can muddy and weaken the signal when the pedal is off2. The v2 carries the concept forward in a housing machined from solid billet aluminum, which Tech 21 describes as heavy duty and built for long life on and off the road1. The original was housed in a chrome-plated, stomp-proof cast-metal enclosure held together with a solid bolt2.
Power and connections
The Killer Wail v2 runs on a standard 9V alkaline battery, which is not included, or on the optional Tech 21 DC9 power supply13. Former Tech 21 supply models #DC2 and #DC4 also work1.
Both Killer Wails are phantom operable via the Fly Rig 5 v2 and the Richie Kotzen Signature RK5 v2 Fly Rig, but only with a modification to the Fly Rigs1. The Richie Kotzen Signature Killer Wail is phantom power operable via the RK5 v3 Fly Rig without that caveat; Premier Guitar notes the RK5 v3 "has also been pre-configured to provide phantom power for Richie's Tech21 Signature RK Killer Wail wah"4.
Killer Wail v2, Killer Blue Wail and limited editions
The current lineup grew out of the Private Stock limited editions. Here is how the three production pedals differ3:
| Pedal | Treadle | Notes |
|---|---|---|
| Killer Wail v2 | Traditional treadle3 | Standard guitar version, 24 oz.3 |
| Richie Kotzen Signature RK Killer Wail | Spring-loaded rocker3 | Returns to bypass when you lift your foot; engages when you press forward3 |
| Killer Blue Wail | Spring-loaded rocker3 | Bass version, keeps the low end intact3 |
The spring-loaded rocker on the Signature and Blue Wail versions returns the treadle to its resting, bypassed position when you remove your foot, and the pedal automatically engages when you press forward3. The Killer Wail v2 keeps a traditional treadle3.
Availability. Premier Guitar reported anticipated worldwide availability of April/May 2025 for all three pedals3. Tech 21's own pages list anticipated worldwide availability of August 2025 for the Killer Wail v21 and April/May 2025 for the Killer Blue Wail5, so the dates differ between sources. A limited amount of the Private Stock Killer Wails was still available in the U.S. on Reverb as of Premier Guitar's report3.
The Killer Blue Wail for bass
The Killer Blue Wail is Tech 21's bass wah. Unlike guitar wahs, Tech 21 says it keeps the low end intact5. It shares the same design goals as the v2, preserving the tonal integrity of vintage wahs while overcoming excessive noise and unreliable mechanical parts, and it weighs the same 24 oz.5. The original Killer Wail was also pitched at bass players: its mode selector switch provided a variety of curves "for bass as well as guitar"2. For more on the category, see bass pedals.
The mode selector: High, Extended and Deep
The original Killer Wail's mode selector switch offers three sweep curves, each described by Tech 21 as wider, smoother and more even than a conventional wah sweep2:
- HIGH: Moves the wah filter to the high range of the guitar, which Tech 21 calls perfect for leads or funky staccato chords2.
- EXTENDED: Tunes the wah to cover the entire range of the guitar. The filter is not so "peaky" in this mode, and Tech 21 recommends it with clean guitars when you want a smooth, wide sweep2.
- DEEP: Moves the filter down to accentuate the lower strings of the guitar2.
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Questions
Does the Killer Wail use a potentiometer?
No. The Killer Wail v2 uses light sensor technology instead of a potentiometer, so there are no clunky pops, no scratching sounds, and no pot to wear out and replace. The treadle position is read optically, which removes the component that most often fails on vintage wahs.
Can you use the Tech 21 Killer Wail on bass?
The original Killer Wail's mode selector was designed for bass as well as guitar, and Tech 21 now makes the Killer Blue Wail, a bass wah that keeps the low end intact, unlike guitar wahs. It shares the same light sensor design and vintage tonal approach as the Killer Wail v2.
What do the High, Extended and Deep modes do?
HIGH moves the wah filter to the high range of the guitar, suited to leads and funky staccato chords. EXTENDED tunes the wah to cover the entire range of the guitar with a less peaky filter, a good choice with clean guitars. DEEP moves the filter down to accentuate the lower strings.
Can the Killer Wail be powered from a Fly Rig?
Yes. Both Killer Wails are phantom operable via the Fly Rig 5 v2 and the Richie Kotzen Signature RK5 v2 Fly Rig with a modification to the Fly Rigs. The Richie Kotzen Signature Killer Wail is also phantom power operable via the RK5 v3 Fly Rig.
How much does the Killer Wail v2 weigh?
The Killer Wail v2 weighs 24 oz. and measures 3.375 inches wide by 8.0 inches long by 1.75 inches high. The Killer Blue Wail bass version weighs the same 24 oz.
Sources (5)
- Killer Wail v2 Wah, Tech 21 NYC, 2025-07-30
- Killer Wail, Tech 21 NYC, 2019-06-23
- Tech 21 Killer Wail Wah Pedals Unveiled, Premier Guitar, 2025-03-03
- Richie Kotzen RK5 Signature Fly Rig V3 by Tech 21, Premier Guitar, 2024-12-21
- Killer Blue Wail Bass Wah, Tech 21 NYC, 2025-07-30
