Gallien-Krueger 400RB-IV preset

Close · 70/100 confidence. Most values readable. Minor gaps filled by inference from similar circuits.

The 400RB-IV is a solid-state Gallien-Krueger bass head, a later version of GK's long-running 400RB. Its single channel has a JFET input with a -14 dB pad, volume, presence and contour controls, an active four-band EQ with hi-mid and lo-mid, and a master. It adds a tuner output with mute, an effects loop, and a balanced direct out with pre/post and ground-lift switches, giving the punchy, bright bass tone the brand is known for.

• Made in: USA
• Wattage: 280W
• Channels: 1

Tags: bass, solid-state, american, high-wattage.

Schematic-derived preset files for 16 Fractal and Line 6 modelers: Axe-Fx II/XL/XL+, Axe-Fx III, FM3, FM9, and the full Helix family (Floor, LT, Rack, HX Stomp, HX Stomp XL, Native).

Gridleak extracts amp parameters from original circuit schematics using AI vision — component values, gain staging, tone stack topology, tube types — then generates native preset files for every supported modeler. Every extraction is scored 0–100 and the score is published.