The MESA/Boogie® Bass 400+, the apex model of MESA’s long-running and storied valve bass amplifier line, reigned supreme throughout the 1980s and 1990s among players seeking to elevate their tone with a boutique-class valve head. Featuring a supremely musical valve preamp, a powerful 7-band graphic EQ, a mighty bank of twelve 6L6 output valves, and a power supply designed to deliver instantaneous pitch, punch, and power on demand, exceptional bass tone was guaranteed. Top artists across genres—from jazz, R&B, funk, and blues to stadium rock, including Sir Paul McCartney—chose the 400+ for its tone both on stage and in the studio, praising its defined attack, clear pitch, and dynamic, lead-the-band character.

Now, the classic receives a modern update, keeping pace with contemporary needs while preserving the nuanced tone of the original, all without the cumbersome size and weight. Introducing the MESA/Boogie Bass-800D, a Class D-powered reimagining of the Bass 400+, combining its sound and attributes with highlights from the successful Subway line of bass products. The valve preamp follows the architecture and sonic cues of the 400+, along with Boogie® Channel topography from the popular Subway TT-800. Additional gain and refined tweaks have been incorporated to achieve an even warmer, valve-enhanced character and expanded capability for subtle, musically relevant overdrive.