The Walrus Audio Mantle Bass Pre-Amp DI in Black is a studio-grade tone shaper designed specifically for electric bass, and it was built in close collaboration with Ian Martin Allison. This is ideal for serious bass players who want their tone dialed in before it hits the amp, interface, or front-of-house. Whether you're playing live, tracking in a studio, or just shaping your sound at home, the Mantle gives you deep, musical control with a design that's both intuitive and powerful.

At its core are Walrus Audio's custom-wound Sapphire input and output transformers. These bring the punch and warmth of classic Neve and API-style preamps, delivering harmonically rich low-end and articulate high-end clarity. You get up to +23dB of clean, magnetic gain, with EQ controls that act more like precision studio filters than traditional pedal shelves. With selectable high-pass and low-pass filters on the Bass and Treble knobs, you can sculpt your tone with surgical accuracy or broad musicality-no mud, no harshness.

This thing is built to be your always-on, pro-level foundation. The JFET input buffer keeps your signal responsive and clear, and the high-headroom +24V internal power gives you massive dynamics without distortion. The Active/Passive pad, ground lift, and simultaneous 1/4" and XLR outputs make it incredibly flexible on any board or in any studio. We've seen a lot of DI/preamp boxes, but the Mantle really feels like the one that gets everything right.

Specifications:

- Input: 1/4" TS Unbalanced, JFET Buffered
- Output: 1/4" TS Unbalanced, XLR Balanced (Transformer-Isolated)
- Power Requirements: 9VDC, 500mA, Center-Negative (Internally Boosted to +24V)
- Input Impedance: 1MΩ
- Output Impedance: 150Ω Balanced, 150Ω Unbalanced
- Gain Range: -6dB to +23dB
- EQ Boost Range: 0dB to +15dB
- EQ Cut Range: -18dB/oct HPF (Bass), -18dB/oct LPF (Treble)
- THD @ 1kHz 1Vrms: 0.04%
- Frequency Response: 20Hz - 20kHz
- Noise Floor: Balanced -101dBV, Unbalanced -94dBV
- Enclosure Size (with knobs): 6.09" x 4.7" x 2.28" (154.78mm x 119.35mm x 57.98mm)
- Switches: Active/Passive Pad (-10dB), Ground Lift
- Controls: Gain, Bass (11-position rotary), Treble (11-position rotary)

Sku: MANTLE