Gallien-Krueger BL250/350/600 Preamp (206-0109-A) - Clean preset

Verified · 83/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The Gallien-Krueger BL250/350/600 preamp series shares a common circuit board across multiple Backline head models. GK designed this architecture to provide consistent clean tone with optional overdrive across an entire product family at various power ratings. The clean channel is the defining characteristic, offering GK's famously tight, articulate bass response.

• Years produced: 2000–2010
• Made in: USA
• Wattage: 600W
• Channels: 2

Tags: american, modern, bass, 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.