Morley Old Blue Rex Brown Wah

A Cult Stage Wah: Rex Brown's "Old Blue"

Rex Brown (Pantera) adopted his Morley Pro Series II Wah in the 1990s, and its character can be heard on iconic albums like The Great Southern Trendkill and Reinventing the Steel. The Morley Old Blue carries the DNA of this wah: same circuit philosophy, through-hole components, and layout close to the original, with a modified sweep to match Rex's preferred setting.

The result aims for an "old school" Morley 1970s approach: a more intense sweep and a design intended to remain highly resistant to electromagnetic interference (EMI), a real advantage when stage lighting, power supplies, and large venues pollute the electrical environment.

Who and What For: Metal Bass, Guitar, Keyboards... and Anything That Needs Bite

Designed for bass (and clearly built for heavy contexts), the Old Blue is not a "niche" wah: it also works very well with guitar and keyboards. It's an ideal pedal if you play metal, hard rock, stoner, sludge, but also alternative rock where a wide and expressive wah can transform a simple riff into a sonic signature.

In live settings, the switchless activation is particularly comfortable: you place your foot, filter, lift your foot, and return to bypass. In the studio, it becomes a sound design tool to sculpt attacks, animate a bass line, or create very vocal filter sweeps without unwanted noise.

Controls, Design, and Key Ergonomic Features

The Morley Old Blue Rex Brown Wah relies on the Morley optical circuit : no potentiometer wear for controlling the sweep, resulting in smooth action and great long-term reliability. The switchless trigger eliminates the "click" of a traditional footswitch and speeds up execution, especially when you need to enter/exit the effect with precise rhythm.

Regarding controls, it's straightforward with a Wah level control that can go up to +15 dB. Useful for compensating a very present wah, standing out in a wall of guitars, or adding a controlled boost before distortion. The pedal also includes a Premium Buffer : on a long pedalboard (multiple pedals + cables), this helps maintain definition and avoid a feeling of dynamic loss.

Finally, stage ergonomics are enhanced by the LED indicator and phosphorescent elements (logo and grip), perfect when the stage is dark and you need to find the pedal "by touch".

Sound

The Old Blue delivers a wide and intense filter, with a sweep that doesn't feel like it "cuts" the low end: the sensation is massive, ideal for aggressive and articulated bass lines. By gently rocking the pedal, you get almost "phaser-like" textures, very musical for making a sustained note breathe or animating a riff.

The response is clear and expressive: the harder you play, the more the wah is felt, and the level control allows you to keep a consistent sound between bypass and effect (or conversely to create a real punch at the filter output). This is typically the kind of wah that embraces its character: present, vocal, and designed to withstand the challenge in a modern metal context. Artist-wise, the imprint is obvious: Rex Brown made it a cornerstone of his identity, both on stage and on several Pantera productions.

Technical specifications

Effects	Wah	Type	sector
Technology	Analog	Use	electric guitar
Format	Pedal	Color	Blue

Signature Model	Rex Brown	Enclosure	metal
Activation	switchless (activated when the foot is placed on it)	Indicator	activation LED
Buffer	Premium Buffer (buffered bypass)	Details	phosphorescent logo and phosphorescent grip
True bypass	no	Dimensions	231.9 mm (L) x 149.3 mm (D) x 69.8 mm (H)
Works with	guitar, bass, keyboards	Power adapter	no
Input	6.35 mm jack (mono)	Power Supply	9 V battery or 9 V DC adapter (center-negative)
Output	6.35 mm jack (mono)	Consumption	approximately 5 mA