Kay K-550 - Ch1 (upper) preset

Close · 78/100 confidence. Most values readable. Minor gaps filled by inference from similar circuits.

The Kay 550 is a mid-1950s tube combo offering a step up from the 500 in power and tonal control, featuring a push-pull output stage and a more developed preamp with separate bass and treble controls. Built in Chicago with straightforward American tube circuit design, it delivers approximately 12 watts of clean, warm tone with responsive dynamics suited to the strumming styles popular in the era. The two-channel design accommodates both guitar and microphone inputs, reflecting the all-purpose demands placed on amplifiers by small performing groups of the 1950s. The Kay 550 is a solid example of mid-decade American budget tube amplification.

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.