RM 420

This product is now discontinued

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  • RM 420
  • RM 420
  • RM 420
  • RM 420

RM 420

This product is now discontinued

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At Ashdown, we know that not every gig pays the big bucks. Dedicated to busy, hard-working bass players on a budget, Rootmaster heads, combos and cabinets draw on all of our experience working with some of the biggest bands in the world to deliver workhorse reliability, creative tone-shaping, comprehensive recording and performing facilities plus the sonic slam you need to underpin your band’s performances night after night – all at a price that won’t break the bank.

Powered by 420W digital amp, the RM420 is the lightest RM head, weighing in at 4kg (8.8lbs) and the perfect choice for working bassists looking for power and features without the weight. 

Simple, powerful EQ 

It all starts with an ultra-low-noise instrument input where the accompanying Input Level control helps you perfectly match the output of your bass. Five-band rotary tone controls act with surgical precision to provide total control over your sound, while a Shape switch instantly dials you in to a classic Ashdown tone setting, straight from the world-famous ABM.

One-knob Compression

Instantly adding warmth and body to your tone, this simple to use, great sounding compressor delivers a powerful, even sound to make sure your bass will fill out any mix.

Footswitchable variable overdrive 

With footswitchable flexibility, our tube-emulated overdrive can take your core bass sound and push it into warm overdrive through to distorted filth whenever you need to add extra grind and girth to your tone. 

Kick it down

Bringing extra depth and definition to your bass parts, the Sub-Harmonic Generator lets you dial in a sub-octave and kick it in via footswitch whenever you need the extra depth for those super-heavy Godzilla moments. 

Totally connected

If you want to use your favourite pedals or multi-effects, you’ll find send and return sockets on the back panel, along with a DI output for direct injection into the PA mixer or recording console and a Line Input (with front panel level control) so you can jam along with a backing track in rehearsal.

Create the perfect rig

A combined Jack/Speakon socket with a minimum 4- ohm load provides flexible partnering options with a dedicated range of Rootmaster cabinets. 2 x 10”, 4 x 10” and 2 x 12” cabs all feature custom-designed Ashdown bass drivers plus a high-frequency horn for additional top-end bite. A 1 x 15” completes the range with all cabinets featuring ultra-cool retro cloth grilles, road-ready tolex covering and tough metal protective corners.


Power Output 420 Watts
Power Requirement 115 - 230V
Speaker Outputs 2 x Jack sockets
Frequency Response -3dB at 17Hz - 30Khz
High Instrument Input Impedance 3.9m Ohms, input range 150mV - 20mV p-p
Low Instrument Input Impedance 1M Ohms, input range 150mV - 10V p-p
Line Input Impedance 10K Ohms, input range 300mV - 40V p-p
Tuner Output  Impedance 22K Ohms, Level 0dBu nominal 
DI Output 600 Ohms balanced, level -20dBu nominal 
Impedance Minimum 4 Ohm 

Bass +/-15dB @ 100Hz Lo Mid +/-15dB @ 220Hz Middle +/-15dB @ 660Hz Hi Mid +/-15dB @ 1.6kHz Treble +/-15dB @ 7kHz shelving Deep +

Effects Send Impedance 22k Ohm, level 0dBu nominal 
Effects Return Impedance 22K Ohm, level 0dBu nominal 

less than 0.5% THD

Signal to Noise Better than 80dB (EQ Flat)
H x W x D (mm)

78 x 313 x 225

Weight (kg) 4


5 Year Warranty

We're so confident in our amplifiers, we offer a 5 year warranty on all new products.

Built for the road

Perfect for gigging bass players, our products are built to last.