Walrus | MANTLE | Analog Bass Preamp / DI Pedal | w/ Sapphire Transformers | PRE-ORDER (Ships March 2026)
or 4x fortnight payments of
$324.75 AUD
with
ⓘ
Born from a collaboration with renowned bassist, touring musician, and educator Ian Martin Allison, the Walrus Audio Mantle bass preamp/DI analog pedal is the studio-grade aural architrave your setup craves. Beating at the heart of Mantle are proprietary, custom-wound Sapphire transformers. This proprietary circuit suite pays homage to myriad Neve and API studio designs, painstakingly crafted to support a prismatic palette of pliable, potent, and precise performances.
Sapphire transformers and visionary sound-shaping potential
In developing the Mantle, the minds at Walrus Audio pored over research, development, and design possibilities, spending more than a year refining the groundbreaking input and output transformers that give the dual-function preamp and DI its distinctive, dynamic aural aperture. The end result? Sapphire transformers — a proprietary custom-wound design that articulates the bleeding edge of modern bass-tone contouring.
Prismatic sonic-contouring control — active or passive power
Behind Mantle’s ergonomic and eye-grabbing Art Deco-inspired interface is a kaleidoscopic array of carefully and intentionally refined sonic-contouring tools, and it all starts with the elegant dual-behavior design of the 2-band EQ. Rather than using continuous encoders, the Bass and Treble band controls feature 11-position rotary switches. Here, satisfying studio-caliber tactility and effortlessly reproducible configurations are only the beginning. With a flat response at the noon position, each successive increase boosts your signal by +3dB, peaking at +15dB for each respective register. The sonic transformation begins as a shelf before evolving into a broad, bell-like musicality. Cutting back from noon, the Bass and Treble controls engage a -18dB/octave highpass and lowpass filter, respectively. Selectable points for the Bass control include 30, 50, 80, 100, and 120Hz, and selectable points for Treble are 8, 6, 4, 2, and 1kHZ.
Uncompromising studio-to-stage connectivity
The beauty of Mantle extends beyond the rich musicality of its aural architecture. It is capable of effortlessly integrating into any studio, stage, rehearsal, or recording rig at virtually any place in your signal path. A brief overview of the signal path is as follows: The 1/4-inch input jack is optimized for electric basses, thanks to its hi-Z design and JFET stage. The signal then enters the filtered or dry EQ path, passing through the input transformer and then the EQ before reaching the output transformer and terminating in a branching path that contains an unbalanced 1/4-inch output and a balanced, male XLR output. Whether you’re taking the DI right into your studio or stage space or sending your sound to other amplification options, Walrus Audio has you covered. The Mantle is equipped with an internal 24-volt power supply to maximize headroom and clarity, as well as a Ground Lift toggle to isolate the XLR DI output from the circuit ground.
- State-of-the-art, dual-function preamp and DI pedal designed in collaboration with celebrated tone titan, touring artist, and educator Ian Martin Allison
- Proprietary, custom-wound Sapphire transformers build on a year-plus of R&D to channel historic Neve and API musicality for unmatched studio-caliber sonics
- Gain control offers up to +23dB of magnetic, transparent tone, straight from the transformer, for unrivaled detail and precision that won’t harsh out
- Custom Bass and Treble controls were co-developed with Ian Martin Allison for an innovative mix of shelving and filtering behaviors
- Rotary-designed Bass and Treble knobs give you satisfying studio-style tactility that’s effortlessly reproducible in any studio or stage arrangement
- JFET input buffer supports myriad electric-bass configurations via hi-Z
- Active/Passive switch lets you introduce a -10dB input pad to effortlessly accommodate active- and passive-design instruments without risking input-stage overload
- Unbalanced 1/4-in. output and balanced XLR-M DI output support versatile signal-routing possibilities to maximize studio and stage utility, at any place in your chain
- Ground Lift switch allows for separating XLR DI output ground from the circuit ground to subdue ground-loop noise and hum
- Internal +24V boost supports immense high-headroom clarity that keeps responsiveness, presence, and power firmly intact