Ashdown Rootmaster UK-RBM-500 500W Bass Amp Head - Ice Blue

Designed for players who want extensive control over their sound without sacrificing portability, the Guitar Center Exclusive Ashdown Rootsmaster Bass Magnifier UK-RBM-500 delivers 500W of output in a compact, UK-built bass amp head. Handcrafted in Essex, England, it builds upon Ashdown’s Rootmaster legacy with an expanded tone-shaping section that includes a Sub-Harmonic Generator for added depth, an onboard compressor for controlling dynamics and a valve-emulated overdrive circuit that ranges from subtle warmth to driven textures. A 5-band EQ and Pre-Shape control provide both detailed adjustment and quick tonal shaping, while dual DI outputs—including an Analogue Cab Sim DI—expand its options for stage and studio use. With an FX loop, headphone output and flexible connectivity, the UK-RBM-500 provides a portable platform for a wide range of bass rigs.

500W Power With Sub-Harmonic Generator, Compression and Drive

The UK-RBM-500 combines a 500W solid-state power section with a suite of tone-shaping tools designed to expand its range. The Sub-Harmonic Generator adds a controllable octave-below layer for increased depth and weight, while the onboard compressor helps manage peaks and smooth dynamics. A valve-emulated overdrive circuit introduces harmonic character, allowing you to dial in warmth, growl or more aggressive textures. Together, these controls provide a flexible foundation for shaping bass tones across a range of playing styles and musical settings.

5-Band EQ and Pre-Shape Control for Detailed Tone Shaping

A flexible 5-band EQ—bass, low-mid, mid, high-mid and treble—provides detailed control across the frequency range, from low-end weight and midrange presence to high-frequency definition. For faster adjustments, the Pre-Shape switch applies a preset tonal contour for quick access to a familiar Ashdown voice. The straightforward control layout keeps adjustments accessible, while the line mix control lets you balance an external source with your instrument signal for additional flexibility.

Analogue Cab Sim DI and Flexible Connectivity for Stage and Studio

For direct applications, the UK-RBM-500 includes both a standard balanced DI output and Ashdown’s Analogue Cab Sim DI, which simulates the response of a miked speaker cabinet when sending the amplifier directly to a PA or recording system. Multiple voicing options allow you to adjust the simulated cabinet response for different applications. An FX loop integrates pedals and external processors, while a headphone output and line input support silent practice and playback. Dual speaker outputs provide flexible cabinet-pairing options for building or expanding a bass rig.

A Compact UK-Built Rootsmaster Bass Amp Head

Handcrafted in the UK and housed in a compact chassis, the Ashdown Rootsmaster Bass Magnifier UK-RBM-500 combines 500W of output with extensive onboard tone shaping and flexible connectivity. Its Sub-Harmonic Generator, compressor, valve-emulated drive and 5-band EQ provide detailed control over the amplifier’s voice, while dual DI outputs expand its usefulness for live sound and recording. Available as a Guitar Center Exclusive, the UK-RBM-500 brings Ashdown’s UK-built Rootsmaster design to bassists seeking a powerful, portable centerpiece for their rig.

Ashdown Amplification Arrives at Guitar Center

Since 1997, Ashdown has built its reputation on powerful, road-ready amplification trusted by bassists on stages around the world. From its iconic Bass Magnifier amps and bass cabinets to pedals, guitar amplification and artist-driven designs, the family-run company has remained dedicated to giving players distinctive tone and dependable performance while renewing its commitment to UK-built craftsmanship. Guitar Center is proud to partner with Ashdown, bringing the brand’s celebrated amplification legacy to musicians nationwide.