Rob Robinette 5F6-A Bassman Micro (Cathodyne) preset

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

Rob Robinette's 5F6A-M Bassman Micro is a DIY build that shrinks the tweed 5F6-A Bassman to about one watt. It keeps the Bassman's bright input stage, cathode-follower-driven bass/mid/treble stack and a 12AY7 cathodyne phase inverter, then drives a single 12AU7 as a push-pull triode power amp. A master volume and tone-bypass switch let it deliver cranked-tweed breakup at bedroom and headphone levels; a 12BH7 can replace the 12AU7 for more power.

• Made in: USA
• Wattage: 1W
• Channels: 1
• Preamp tubes: 1× 12AY7, 1× 12AX7
• Power tubes: 1× 12AU7 (both triodes push-pull)

Tags: diy, american, tweed, low-wattage, breakup, crunch, practice.

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.