Ashdown Engineering

ABM-600-EVO IV Head


Unleash your bass's true potential with the Ashdown ABM EVO IV. For over two decades, the ABM range has been the go-to choice for bassists seeking unrivalled tone, versatility, power, and reliability. Now in its fifth iteration, the ABM EVO IV pushes the boundaries further.

The 600W head features the Variable Valve Drive Plus, offering an array of clean to overdriven tones at your fingertips. The new 9-band EQ, with precision controls, ensures you find your perfect sound effortlessly. And let's not forget the Input VU meter, which streamlines the setup process. 

ABM EVO IV retains beloved features like the One Knob Dynamic Compressor and the Sub-Harmonic Generator, enriching your bass notes with depth and character. Professional connectivity options, including a tuner output, transparent FX loop, and Line Input, make this head stage-ready and studio-friendly.

With flexible foot-switching capabilities, you can control Valve Drive, Compression, EQ, and Sub-Harmonic Generation on the fly, giving you countless sound combinations without extra pedals. Elevate your bass playing with the Ashdown ABM EVO IV.

Please Note:

Direct purchases NOT available in the United States

Find your local Ashdown Dealer HERE


  • Power Output - 600 Watts
  • Power Requirement - 115-230 Volts
  • Speaker Outputs - 2 x Jack/Speakon outputs
  • Frequency Response - -3dB @ 17Hz und 30KHz
  • High Instrument Input - Impedance 3.9m Ohms, input range 150mV
  • Low Instrument Input - Impedance 22k Ohms, input level 0dBu nominal
  • Line Input - Impedance 22k Ohms, input level 0dBu nominal

  • DI Output - 600 Ohm balanced, Level 0dBu nominal
  • Tuner Output - Impedance 22k Ohms, Level 0dBu nominal
  • Effects Send - Impedance 22k Ohm, Level 0dBu nominal
  • Effects Return - Impedance 22k Ohms, Input Level 0dBu Nominal
  • H x W x D (mm) - 146 x 489 x 336
  • Weight (kg) - 12.5

Ashdown ABM 600 evo iv head variable valve drive plus
Variable Valve Drive Plus – from zero to rock hero!
Our Variable Valve Drive preamp section has also been upgraded in EVO IV. Delivering more current to the 12AX7 tube enables more drive and harmonic content than ever before, enabling players to dial in a sound from pristine clean, to the fattest, fullest bass overdrive currently available. The Drive level can be preset and kicked in and out via footswitch, providing access to a huge range of clean, warm and overdriven tones.
Ashdown ABM 600 evo iv head eq controls
The best EQ in the business, just got better!
Bassists plugging into EVO IV will be greeted straight away by the flickering of the new Input VU meter, allowing them to quickly find the sweet spot for their instrument. From there, EVO IV features a sophisticated 9-band EQ, with familiar Bass, Middle and Treble controls and six sliders providing precision cut and boost at 100Hz, 180Hz, 340Hz, 1.3KHz, 2.6KHz and 5KHz. The EQ can be switched in via footswitch taking the player from a flat fretless sound to their favourite EQ setting instantly. The NEW 9-band EQ is a revelation of sonic perfection and will surprise older ABM users.
Ashdown ABM 600 evo iv head one knob compressor
One knob compressor
Other ABM favourite features are retained in EVO IV, including Ashdown’s famous One Knob Dynamic Compressor sub octave note for huge bass tones. Kick it in and this simple to use, great sounding compressor delivers a powerful, even sound, guaranteed to help your bass fill out any mix.
Ashdown ABM 600 evo iv head subharmonic generator control
Sub-Harmonic Generator
Once heard – never forgotten. The ABM Sub-Harmonic generator adds an octave below the notes being played bringing fullness to any bass part. The Sub level is independently controllable, letting you dial in anything from a subtle hint of deep bass to a full-on subterranean funk.
Ashdown ABM 600 evo iv head professional connections including speakon and jack sockets
Professional Connections
Not that you'd expect any less, ABM is loaded with connectivity. A tuner output, Line out, transparent FX loop and a Line Input for the connection of an external sampler or sound source. Output muting cuts the signal from the DI output but leaves the tuner output 'live', allowing the player to tune up in silence.

A pair of Neutrik Jack/Speakon sockets with a minimum 4 ohm load provide flexible partnering options with a dedicated range of ABM EVO IV cabinets. The ABM 600 EVO IV can be used to power a single 8 ohm cabinet, a pair of 8 ohm cabinets or a single 4 ohm cabinet.
Ashdown fs 4 footswitch
Flexible Footswitching
Paired with our FS-4 footswitch (not included) the ABM comes alive for onstage use, enabling on-the-fly tonal gearshifts. With footswitchable Valve Drive, Compression, EQ and Sub Harmonic Generator, ABM puts dozens of sound combinations at your feet, without so much as an effect pedal in sight.


Click the link to see more ABM videos!


ABM 600 User Manual
ABM 600 Data Sheet

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