Gibson Atlas IV preset

Verified · 86/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The Atlas IV is a 1960s Gibson bass amplifier with one channel, two inputs and a 15-inch 16-ohm speaker. A 6EU7 input stage feeds a bass and treble network and a volume, then the second 6EU7 half and a 6C4 gain stage, and a 6EU7 long-tail phase inverter drives a fixed-bias push-pull pair of 6L6s. The supply uses silicon diodes with a filter choke and a power/polarity/standby switch.

• Made in: USA
• Wattage: 35W
• Channels: 1
• Preamp tubes: 2× 6EU7, 1× 6C4
• Power tubes: 2× 6L6

Tags: american, vintage, bass, 6l6.

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.