Walrus Audio has officially raised the bar for low-end signal processing with the release of The Mantle, a premium analog bass preamp and DI pedal. Developed in rigorous collaboration with renowned bassist and educator Ian Martin Allison, The Mantle is designed to serve as the “impeccable foundation” for any bass rig, whether in the studio, on a global tour, or in a home recording suite.
Priced at $749.99/£719.00, The Mantle isn’t just a utility pedal—it is a sophisticated tonal workstation that bridges the gap between classic British console warmth and American precision.
The Heart of the Tone: Sapphire Transformers
The standout feature of The Mantle is the inclusion of Walrus Audio’s proprietary Sapphire Transformers. After more than a year of research and development, the engineering team has successfully fused two iconic “flavors” of audio history into one enclosure:
-
The Input Stage (Neve-Inspired): Based on classic Neve circuitry, the input transformer delivers an authoritative low-end and a mid-range “push” that handles high-output signals with ease and zero unwanted distortion.
-
The Output Stage (API-Inspired): Based on the legendary API 312 output stage, this transformer balances the signal for long cable runs while adding the airy, articulate harmonic content that professional engineers crave.
Studio-Level Precision with “Smart” EQ
Unlike standard pedals with simple shelving filters, it features a dual-behavior EQ system controlled by eleven-position rotary switches. This ensures that session players can perfectly reproduce their settings every time.
-
Boosting (Positions 7-11): Each click adds +3dB (up to +15dB), starting as a shelf and transitioning into a broad, musical bell.
-
Cutting (Positions 1-5): Instead of just lowering volume, cutting introduces steep -18dB/octave filters. The Bass control becomes a High-Pass Filter (30Hz–120Hz), and the Treble control becomes a Low-Pass Filter (1kHz–8kHz), allowing users to surgically remove “mud” or “fizz” without losing the core of their tone.
Built for the Modern Professional
The Mantle is housed in a robust die-cast enclosure and internally boosts standard 9V power to +24V. This massive internal voltage provides “tremendous headroom,” ensuring that even the most aggressive transients from active five-string basses remain clean and dimensional.
The unit features a high-quality JFET buffer, a -10dB pad for high-output instruments, and a transformer-balanced XLR output with a ground lift for noise-free performance in any venue.
FAQ: Everything You Need to Know
Is The Mantle suitable for active or passive basses?
Yes. It features a high-impedance (1MΩ) input with a JFET buffer. For high-output active electronics, a -10dB pad switch is included to prevent clipping the input stage.
What power supply does The Mantle require?
It requires a standard 9V DC (center-negative) power supply providing at least 500mA. It is highly recommended to use an isolated power supply to maintain the pedal’s ultra-low noise floor (-101dBV).
Can I use this as a standalone DI for recording?
Absolutely. The Mantle is designed to be a “studio-grade” front end. The transformer-balanced XLR output allows you to go directly into an audio interface or mixing console with a fully realized, professional tone.
What makes the EQ different from a standard bass pedal?
Most pedals use simple “boost/cut” knobs. The Mantle uses fixed rotary positions for recallability and shifts its behavior from shelving (when boosting) to steep filtering (when cutting), offering much more control over the mix.
Technical Specifications at a Glance
| Feature | Specification |
| Circuitry | All-Analog with Sapphire Transformers |
| Internal Voltage | +24V (from 9V input) |
| Gain Range | -6dB to +23dB |
| Frequency Response | 20Hz – 20kHz |
| THD @ 1kHz | 0.04% |
| Outputs | 1/4″ Unbalanced, XLR Balanced DI |
Conclusion
The Walrus Audio Mantle is more than a preamp; it is a commitment to tone. By combining the “Big Two” of console history—Neve and API—into a pedalboard-friendly format, Walrus Audio and Ian Martin Allison have created a tool that ensures your bass is heard in its most “confident, fully realized form.”
For the bassist who refuses to compromise on their fundamental sound, The Mantle could well be the new industry standard.
Price & Availablity
Available to pre-order now at select Walrus Audio dealers.
More Information
#Walrus Audio
This article may contain affiliate links to Andertons, DeathCloud, Donner, Fender, Gear4Music, Positive Grid, Sweetwater, and Thomann that help finance the running costs of GuitarBomb. We will receive a small commission if you buy something through these links. Don’t worry; you pay the same price, and it costs you no extra to use these affiliate links for your purchases.
