The Variable Valve Drive preamp in the ABM EVO IV has been completely re-engineered to deliver even more harmonic richness and dynamic drive. By pushing more current through the 12AX7 tube, players now have access to the widest spectrum of bass overdrive ever offered in an ABM - from crystal-clear, articulate cleans to thunderous, full-bodied distortion. With the drive level presettable and footswitchable, this section makes it effortless to jump between subtle warmth and stage-shaking growl.

Next-Level EQ Control

EVO IV introduces an enhanced 9-band EQ system, bringing precision tonal shaping to new heights. Alongside the familiar Bass, Middle, and Treble controls, six additional sliders allow exact boost and cut at 100Hz, 180Hz, 340Hz, 1.3kHz, 2.6kHz, and 5kHz, ensuring total command of your sound. The new Input VU meter makes it easy to find the perfect gain sweet spot for your instrument, while a footswitchable EQ lets you toggle between flat tones and your customized settings instantly.

One-Knob Dynamic Compressor

A cornerstone of the ABM range, the one-knob compressor is retained in EVO IV. This intuitive control delivers smooth, even dynamics with the flick of a switch, ensuring your bass tone remains punchy, balanced, and mix-ready. Whether you’re underpinning a live band or tracking in the studio, this compressor guarantees a professional polish without overcomplicating.

Professional Connectivity

Designed with working bassists in mind, the EVO IV provides a wealth of professional-grade connections. A dedicated tuner out, transparent FX loop, line input for samplers or external sources, and line out cover every performance or recording need. The output mute function ensures silent tuning by cutting the DI while keeping the tuner live - ideal for seamless stage setups.