UK-RBM-500
UK-RBM-500
UK-RBM-500

Ashdown Engineering

UK-RBM-500

£799.00

Please note: All UK-built products are made to order. The approximate lead time is 20 days.

For more information, please email: info@ashdownmusic.co.uk

The Ashdown UK-RBM-500 (Rootmaster Bass Magnifier) is a UK-built, Ice Blue lightweight 500 watt bass head crafted for players who want punchy performance in a highly portable format. Equipped with Sub-Harmonic Generator, smooth Compression, expressive Valve-Emulated Overdrive, a useful FX Loop, and both DI and Ashdown’s Analogue Cab Sim DI outputs, it delivers refined tone-shaping options for stage, studio, and silent practice through its dedicated Headphone Out.

Compact but impressively capable, the UK-RBM-500 offers the clarity, warmth and reliability that define the RBM series.

Pairs well with

Ships within 1-2 business days (UK Customer Orders Only)

5 Year Warranty

Engineered to Last, Trusted by the Best

Product Specifications

POWER

• Power Output: 500 Watts
• Power Requirements: 115–230 Volts
• Impedance: Minimum 4 Ohms

CONNECTIVITY & I/O

• Speaker Outputs: 2 × Neutrik Speakon/Jack outputs
• High Instrument Input: Impedance 3.9M Ohms, input range 150mV
• Low Instrument Input: Impedance 10k Ohms, input range 300mV – 405V p-p
• Line Input: Impedance 22k Ohms, input level 0dBu nominal
• DI Output: 420 Ohm balanced, Level 0dBu nominal
• Effects Send: Impedance 22k Ohm, Level 0dBu nominal
• Effects Return: Impedance 22k Ohms, Input Level 0dBu nominal

PERFORMANCE

• Frequency Response: –3dB @ 17Hz and 30kHz
• Signal to Noise: Better than 80dB (EQ flat)
• EQ:
• Bass: ±15dB @ 100Hz
• Lo Mid: ±15dB @ 340Hz
• Middle: ±15dB @ 660Hz
• Hi Mid: ±15dB @ 1.6kHz
• Treble: ±15dB @ 7kHz shelving
• Distortion: Less than 0.5% THD

DIMENSIONS & WEIGHT

• Height: 89 mm
• Width: 311 mm
• Depth: 235 mm
• Net Weight: 2.5 kg

Rootmaster DNA, Refined in the UK

The Ashdown UK-RBM-500 (Rootmaster Bass Magnifier) channels the essence of the Rootmaster philosophy into a UK-built amplifier finished in striking Ice Blue. Inspired by the RM-500-EVO III and reimagined for today's players, this lightweight 500-watt head is designed to deliver confident, articulate bass tone in a compact, highly portable format - ideal for musicians constantly moving between rehearsals, gigs, studio sessions, and home use.

Precision Tone Control

At the heart of the UK-RBM-500 is a carefully curated set of tone-shaping tools that allow bassists to sculpt their sound with accuracy and musicality. Whether dialling in subtle refinement or bold character, the amp offers responsive control that adapts effortlessly to both modern and traditional bass approach.

Weight, Warmth, and Character

The Sub-Harmonic Generator introduces a rich octave-below layer that adds depth and authority to your low end, enhancing everything from tight contemporary lines to classic bass foundations. The onboard Compressor provides smooth, even dynamic control, while Ashdown's valve-emulated Overdrive circuit delivers a wide tonal range - from gentle warmth to assertive growl and full-bodied grit.

Ready for Any Signal Chain

An onboard FX Loop allows external pedals and processors to slot naturally into the signal path, preserving the amp's core character. For direct use, the UK-RBM-500 includes both a standard DI output and Ashdown's Analogue Cab Sim DI, recreating the response of a mic'd Ashdown cabinet - perfect for in-ear monitoring, recording environments, and consistent front-of-house tone.

Compact, Capable, and Built to Last

User

manual

CLICK THE IMAGE ABOVE TO DOWNLOAD THE USER MANUAL

FAQs

Please read our FAQs page to find out more.

How Long Will My Order Take To Arrive?

Orders placed before 3pm (Monday-Thursday) are dispatched on the same day. UK Customer orders are shipped on a next-day delivery service via TNT.

Do You Shop To Outside Of The UK?

Currently, we do not facilitate orders to outside of the UK. If there is a specific product that you are after, be sure to check our Dealer Locator to find your closest Ashdown dealer!

If you cannot find a local dealer, please do not hesitate to get in touch and we will try and assist!

Do Ashdown Products Come With A Warranty?

Yes! All Ashdown product purchased include a 5 year warranty, giving you peace of mind and long-term support.

For more information on warranties, visit our Warranty Info page!

Where Can I Buy Ashdown Spares and Accessories?

Spare parts, footswitches, and accessories can be purchased directly through our in-house service team. If you're looking for something specific, our team will be happy to point you in the right direction!

How Can I Contact Ashdown Support?

Our passionate UK-based team is always ready to help. You can get in touch by phone or email, and we'll be happy to assist with any questions.

Didn’t find your answer?

Don't hestitate to contact us