Formula 5F6

The Catalinbread Formula 5F6 recreates the Fender 5F6-A Tweed Bassman, arguably the most influential amplifier circuit ever designed. Jim Marshall copied it wholesale for the JTM45, and from there it spawned virtually every British amp that followed. Buddy Holly, Stevie Ray Vaughan, and Buddy Guy all ran through Bassmans.

The Formula 5F6 reproduces the Bassman's tone stack part-for-part, giving you a full three-band EQ with Treble, Middle, and Bass controls. An internal Stock Bassman / Secret Lead voicing switch changes the gain structure, and an internal presence trimpot provides additional high-frequency fine-tuning. This gives it the widest tonal range of any Formula variant.

Forty-five watts through dual 5881s into a 4x10 cab produced a sound that sat perfectly between Fender sparkle and the raw aggression that Marshall would later make famous. The Formula 5F6 captures that crossover point. Runs on 9-18V DC.