{"product_id":"walrus-audio-mantle-bass-pre-amp-di","title":"Walrus Audio Mantle Bass Pre-Amp\/DI Black","description":"\u003cp\u003e\u003ciframe width=\"560\" height=\"315\" src=\"https:\/\/www.youtube.com\/embed\/nV7i5NvvDmE?si=OlyKLytVjItXGWqr\" title=\"YouTube video player\"\u003e\u003c\/iframe\u003e\u003c\/p\u003e\n\u003ch2 dir=\"auto\" class=\"PDq2pG_selectionAnchorContainer\"\u003eProduct Description\u003cspan class=\"PDq2pG_selectionAnchor\"\u003e\u003c\/span\u003e\n\u003c\/h2\u003e\n\u003cp dir=\"auto\"\u003eThe \u003cstrong\u003eWalrus Audio Mantle Bass Preamp \u0026amp; DI\u003c\/strong\u003e is a premium analogue preamp and direct box developed in close collaboration with bassist \u003cstrong\u003eIan Martin Allison\u003c\/strong\u003e. Designed for stage, studio and home use, Mantle provides a refined foundation for electric bass with extensive headroom, musical gain, flexible EQ and transformer-balanced output.\u003c\/p\u003e\n\u003cp dir=\"auto\"\u003eAt the heart of Mantle are Walrus Audio’s proprietary \u003cstrong\u003eSapphire Transformers\u003c\/strong\u003e. The input transformer draws from classic Neve-style architecture for authoritative low end and midrange presence, while the output transformer is based on the output stage of an API 312, providing balanced output alongside rich harmonic character.\u003c\/p\u003e\n\u003cp dir=\"auto\"\u003eA high-impedance \u003cstrong\u003eJFET input buffer\u003c\/strong\u003e preserves detail and playing dynamics before the signal reaches the transformer gain stage. Gain is adjustable from \u003cstrong\u003e-6dB to +23dB\u003c\/strong\u003e, providing everything from attenuation to clean, harmonically rich amplification.\u003c\/p\u003e\n\u003cp dir=\"auto\"\u003eThe Bass and Treble controls use 11-position rotary switches with a flat setting at position six. Boost settings provide up to \u003cstrong\u003e+15dB\u003c\/strong\u003e in 3dB increments, while the cut positions introduce selectable high-pass and low-pass filtering for precise control over the frequency extremes.\u003c\/p\u003e\n\u003cp dir=\"auto\"\u003eMantle operates internally at \u003cstrong\u003e+24V\u003c\/strong\u003e for increased headroom and clean low-frequency response. A -10dB Active\/Passive pad accommodates higher-output instruments, while Ground Lift helps address ground-loop noise when using the balanced XLR output.\u003c\/p\u003e\n\u003cp dir=\"auto\"\u003eWith unbalanced 1\/4\" input and output plus a transformer-balanced XLR DI output, Mantle provides a flexible central preamp for sending a polished bass signal to an amplifier, interface, mixer or additional effects.\u003c\/p\u003e\n\u003ch2 dir=\"auto\"\u003eKey Features\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDeveloped with bassist Ian Martin Allison\u003c\/li\u003e\n\u003cli\u003ePremium analogue bass preamp and DI\u003c\/li\u003e\n\u003cli\u003eProprietary custom-wound Sapphire input and output transformers\u003c\/li\u003e\n\u003cli\u003eHigh-impedance JFET input buffer\u003c\/li\u003e\n\u003cli\u003eTransformer-based gain from -6dB to +23dB\u003c\/li\u003e\n\u003cli\u003e11-position Bass and Treble controls\u003c\/li\u003e\n\u003cli\u003eUp to +15dB of musical EQ boost\u003c\/li\u003e\n\u003cli\u003eSelectable high-pass and low-pass filtering\u003c\/li\u003e\n\u003cli\u003eTransformer-balanced XLR DI output\u003c\/li\u003e\n\u003cli\u003eInternally boosted to +24V for increased headroom\u003c\/li\u003e\n\u003cli\u003e-10dB pad for active and high-output basses\u003c\/li\u003e\n\u003cli\u003eGround Lift for live and studio setups\u003c\/li\u003e\n\u003cli\u003eFlexible 1\/4\" and balanced XLR routing\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2 dir=\"auto\"\u003eControls\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eGain:\u003c\/strong\u003e -6dB to +23dB of transformer-based gain\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBass:\u003c\/strong\u003e 11-position boost\/cut and high-pass filter control\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTreble:\u003c\/strong\u003e 11-position boost\/cut and low-pass filter control\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eActive \/ Passive:\u003c\/strong\u003e Engages a -10dB input pad when required\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eGround Lift:\u003c\/strong\u003e Separates XLR output ground from circuit ground\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2 dir=\"auto\"\u003eEQ\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eBass and Treble Controls: 11 Positions Each\u003c\/li\u003e\n\u003cli\u003eFlat Position: Position 6\u003c\/li\u003e\n\u003cli\u003eBoost Positions: 7–11\u003c\/li\u003e\n\u003cli\u003eBoost Increment: +3dB Per Position\u003c\/li\u003e\n\u003cli\u003eMaximum EQ Boost: +15dB\u003c\/li\u003e\n\u003cli\u003eBass Cut: -18dB\/oct High-Pass Filter\u003c\/li\u003e\n\u003cli\u003eBass HPF Frequencies: 30Hz, 50Hz, 80Hz, 100Hz, 120Hz\u003c\/li\u003e\n\u003cli\u003eTreble Cut: -18dB\/oct Low-Pass Filter\u003c\/li\u003e\n\u003cli\u003eTreble LPF Frequencies: 8kHz, 6kHz, 4kHz, 2kHz, 1kHz\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2 dir=\"auto\"\u003eSpecifications\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eBrand: Walrus Audio\u003c\/li\u003e\n\u003cli\u003eModel: Mantle\u003c\/li\u003e\n\u003cli\u003eProduct Type: Bass Preamp \/ DI\u003c\/li\u003e\n\u003cli\u003eInput Buffer: High-Impedance JFET\u003c\/li\u003e\n\u003cli\u003eTransformers: Walrus Audio Sapphire Input and Output Transformers\u003c\/li\u003e\n\u003cli\u003eSignal Path: JFET Buffer → LPF\/HPF or Dry Path → Input Transformer → Boost EQ → Output Transformer\u003c\/li\u003e\n\u003cli\u003eGain Range: -6dB to +23dB\u003c\/li\u003e\n\u003cli\u003eEQ Boost Range: 0dB to +15dB\u003c\/li\u003e\n\u003cli\u003eActive Bass Pad: -10dB\u003c\/li\u003e\n\u003cli\u003eInput: 1 × 1\/4\" TS Unbalanced\u003c\/li\u003e\n\u003cli\u003eInstrument Output: 1 × 1\/4\" TS Unbalanced\u003c\/li\u003e\n\u003cli\u003eDI Output: Male XLR Balanced\u003c\/li\u003e\n\u003cli\u003eInput Impedance: 1MΩ\u003c\/li\u003e\n\u003cli\u003eBalanced Output Impedance: 150Ω\u003c\/li\u003e\n\u003cli\u003eUnbalanced Output Impedance: 150Ω\u003c\/li\u003e\n\u003cli\u003eBalanced Noise Floor: -101dBV\u003c\/li\u003e\n\u003cli\u003eUnbalanced Noise Floor: -94dBV\u003c\/li\u003e\n\u003cli\u003eTHD at 1kHz \/ 1Vrms: 0.04%\u003c\/li\u003e\n\u003cli\u003eFrequency Response: 20Hz–20kHz\u003c\/li\u003e\n\u003cli\u003eInternal Operating Voltage: +24V\u003c\/li\u003e\n\u003cli\u003ePower Requirement: 9V DC, 500mA\u003c\/li\u003e\n\u003cli\u003ePolarity: Centre Negative\u003c\/li\u003e\n\u003cli\u003ePower Connector: 2.1mm\u003c\/li\u003e\n\u003cli\u003ePower Supply: Not Included\u003c\/li\u003e\n\u003cli\u003eRecommended Power: Isolated Power Supply\u003c\/li\u003e\n\u003cli\u003eDimensions: 154.78 × 119.35 × 57.98mm including knobs\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp dir=\"auto\"\u003e \u003c\/p\u003e","brand":"Walrus Audio","offers":[{"title":"Default Title","offer_id":46212828659756,"sku":"900-1103","price":1199.0,"currency_code":"AUD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/2161\/9961\/files\/Mantle_left_1800x_e8c15a39-7f98-441d-abc7-a4ebe68a4f0d.webp?v=1790145983","url":"https:\/\/guitarfactory.net\/products\/walrus-audio-mantle-bass-pre-amp-di","provider":"Gladesville Guitar Factory","version":"1.0","type":"link"}