Catalinbread Formula 5F6

A Tweed Bassman, the "bass" amp that became a guitar reference

The Formula 5F6 is designed as a pedal translation of the Bassman tweed spirit: a circuit born for bass but quickly adopted by guitarists for its harmonic richness, bright top end, and grain that "breaks up" beautifully when you push the volume. Here, the idea is the same: to capture that feeling of a living amp, shifting from a wide, snappy clean to expressive breakup, then to a dense crunch, without losing note clarity.

And to go beyond simple vintage reproduction, the circuit also offers an internal setting that "supercharges" the response: more gain and an adjusted tone for bigger sounds while maintaining clear definition.

Who is the Formula 5F6 for?

This pedal is aimed at guitarists who want an amp-driven sound at controlled volume, both in studio and live settings, and those seeking a foundational tone ("always-on") rather than a compressed modern overdrive saturation. It excels in blues, classic rock, roots, country, garage... but can also serve as a platform for heavier styles when stacked with a boost, fuzz, or another overdrive.

Its very responsive behavior makes it particularly rewarding for players who use a pick with nuance or control saturation via the guitar's volume knob. With single-coils, you get a superb "tweed" sparkle; with humbuckers, you reach crunch and grit more quickly.

Settings, modes, and design: the "amp" approach on a pedalboard

The Formula 5F6 adopts a preamp-style ergonomics: Gain to adjust the amount of drive, Volume for output level, and especially a 3-band EQ (Treble, Middle, Bass) that lets you recreate the behavior of an amp tone stack, with a real impact on playing feel and mix placement. This is a major asset for moving from a bright, spacious clean to a tighter crunch, or conversely to keep punchy lows without muddying the bottom end.

Inside, a presence control allows fine-tuning of brightness and upper-mid openness, while an internal mode selector provides access to a second, more "pumped-up" voice: more gain, clearer attack, and bigger sounds, perfect for launching a solo or thickening a riff.

The Sound

The character of the Formula 5F6 is this blend of brightness and organic grain: an attack that tightens slightly (fast compression), then a sound that "breathes" and opens up, with glassy highs, full lows, and a nice sense of depth. At low gain, it adds definition and a touch of amp-like harmonics just pushed enough; increasing Gain leads to an extremely musical breakup, then to a thick, creamy crunch that retains clarity.

This modern "tweed" signature is also found on rock and roots-oriented pedalboards: the pedal is notably spotted in setups of artists like Taylor Goldsmith, G. E. Smith, or Nick Godwin, proving it can handle nuanced rhythmic playing as well as more biting textures when pushed.

Technical specifications

Effects	Preamp, Overdrive, Amp Simulator	Type	sector
Technology	Analog	Use	electric guitar
Format	Pedal	Color	Grey
EQ	3 channels

Sound character	tweed Bassman (dynamic response and "amp-like" tone)	Dimensions	110 x 60 x 50 mm (approximately)
Controls	Volume, Gain, Treble, Middle, Bass	Weight	0.18 kg (approximately)
Internal settings	presence (trim), mode selector ("stock" voicing / enhanced-gain voicing)	Manufacture	USA
Input	1 x 6.35 mm jack (mono)	Documentation	included
Output	1 x 6.35 mm jack (mono)	Power supply	not included
True bypass	yes	Required power supply	9V to 18V DC (center-negative)
Footswitch	1	Consumption	5 mA
Chassis	metal