Ampeg SB-12 (7868 Version) - Instrument preset

Verified · 85/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

This is a service bulletin or schematic document (reference SB-127868) for an Ampeg Portaflex amplifier, representing a specific factory revision or engineering change notice applied to the Portaflex line. Ampeg's Portaflex series featured a distinctive flip-top cabinet design where the amplifier head folded into the speaker cabinet for transport. The SB designation suggests this document was issued to address a circuit modification or component substitution approved by Ampeg engineering.

• Made in: USA

Tags: american.

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.