Masco MAP-15 preset

Verified · 92/100 confidence. Complete schematic. All component values readable. Parameters derived directly from the circuit.

The MAP-15 (Sams Photofact 1947) is a three-input, five-valve amplifier. 6SL7 twin triodes handle the inputs (one set up for a crystal microphone), tone and paraphase inversion, driving two cathode-biased 6L6GAs in push-pull from a 5Y3GT rectifier. Masco (Mark Simpson Manufacturing Co.) built PA and instrument amplifiers in New York, and many are now converted for guitar.

• Made in: USA
• Wattage: 15W
• Channels: 1
• Preamp tubes: 2× 6SL7
• Power tubes: 2× 6L6GA

Tags: american, vintage, 6l6, low-wattage.

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.