Ampeg B4R (preamp) - Ch 1 preset

Close · 75/100 confidence. Most values readable. Minor gaps filled by inference from similar circuits.

The B4R is a professional solid-state bass head delivering 1000 watts in a rack-mount format. The Ch 1 preamp provides Ampeg's characteristic bass tone shaping with extensive EQ options. The B4R was aimed at touring professionals who needed maximum power and reliability from a solid-state design.

• Years produced: 1998–2004
• Made in: USA
• Wattage: 1000W
• Channels: 1

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

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.