The Morley Pro Series II Wah is a wah pedal from Morley's 1992 redesign of its wah line, the redesign that introduced Switchless Activation and converted Morley's classic wah circuits to modern optics1. Instead of a footswitch, the pedal switches on and off through the movement of the treadle, so pushing the pedal down brings the effect in and letting it back up takes it out. Morley has built its reputation on Switchless Activation and optical wah designs since then2, and the company describes the 1992 redesign as having produced "the first Switchless activation Wah"31.
Circuit lineage and the Old Blue connection
The Pro Series II's circuit comes from that 1992 redesign. Morley's own product page for the current signature version states: "The circuit is derived from Morley's 1992 redesign, which introduced Switchless Activation and converted their classic Wah circuits to modern optics"4.
The pedal is best known today through Rex Brown, the Pantera bassist, who "acquired his Pro Series II Wah \"Old Blue\" in the 1990's"5. In January 2025 Morley released the Morley Rex Brown Old Blue Wah, a modified recreation of Brown's pedal with a sweep adjusted to evoke 1970s Morley wahs, launched as the first release of Morley's new Classic Series range14.
"acquired his Pro Series II Wah \"Old Blue\" in the 1990's"
Where it sits in Morley's wah range
The Pro Series II belongs to the switchless, optical branch of Morley's wah designs, the approach that carries through to current pedals such as the Morley 20/20 Classic Switchless Wah, the Morley Bad Horsie 2 and the Morley Tye Trujillo TruDrive Wah. For the wider picture of how these designs differ, see the Wah-Wah Pedals page412.
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Questions
Why is the Pro Series II Wah associated with Rex Brown?
Rex Brown acquired his Pro Series II Wah, which he nicknamed Old Blue, in the 1990s and used it as his bass wah. In 2025 Morley released the Rex Brown Old Blue Wah, a modified recreation of that pedal with a sweep adjusted to evoke 1970s Morley wahs, as the first release of its Classic Series range.
What does Switchless Activation mean on a Morley wah?
Switchless Activation is Morley's design, introduced with the 1992 redesign, that turns the wah on and off through the pedal's travel rather than a footswitch. The Pro Series II uses this approach along with the modern optical circuitry that replaced the older designs.
Sources (5)
- Morley Unveils the Rex Brown Signature Old Blue Bass Wah, Bass Magazine, 2025-01-16
- “We want an entire new generation of players to be able to experience the exact same pedal that Cliff used”: Morley salutes late Metallica bass icon Cliff Burton with the Tribute Power Wah Fuzz reissue, MusicRadar, 2024-02-20
- Morley 50th Anniversary Press Release, Morley, 2019-01
- Rex Brown Old Blue Wah, Morley
- Morley Rex Brown Old Blue Wah, Pedal of the Day, 2025-03-30
Rex Brown
