Boss FA-1 FET Amplifier

The Boss FA-1 FET Amplifier is a portable, compact clean boost and preamp pedal made by Boss, originally released as part of the Boss Pocket Series in early 1984¹²³. It is an analog circuit built around a field-effect transistor input buffer coupled to dual operational amplifiers, and RockBoard's PedalPedia describes it as providing transparent signal enhancement or pushed overdrive depending on where you set the volume knob¹. Housed in a distinctive green enclosure, it was designed with an integrated belt clip for mobile use without a traditional footswitch, and it relies on an always-on architecture rather than a bypass switch¹.

The FA-1 is a rare pedal today, and that rarity is part of what makes it desirable; several decent clones are available from other makers, which is how most players now get the circuit⁴.

The controls

The FA-1 keeps its control set simple: a volume knob plus bass and treble knobs, along with a low-cut switch². The volume knob functions as an adjustable gain control within the op-amp feedback loop, which is what lets it run from a clean lift all the way to pushed overdrive¹. The bass and treble controls sit in an active Baxandall two-band equalization section, the same EQ approach Boss used across its preamp designs of the era¹.

The low-cut switch is the one toggle on the unit. It engages a filter at 200Hz with a slope of -6dB per octave, rolling off everything below that point⁴. For a player pushing an amp into overdrive, cutting the sub-200Hz content tightens the low end and keeps the drive from getting flubby, which is a common reason the switch is there on preamp circuits of this kind.

A Boss Pocket Series pedal from the early '80s

In early 1984 Boss released two strange new devices under the name "The Pocket Series," and the FA-1 FET Preamp was one of them³. Writing on Boss's own history pages, Rod Brakes notes that the FA-1 FET Amplifier sported the same array of knobs, Volume, Treble, and Bass, along with a low-cut switch, tying it to Boss's earlier preamp work². The pedal was developed in the early '80s as a compact, battery-powered preamp a player could clip to a belt rather than stomp on stage¹⁵.

Rory Gallagher, David Gilmour, and The Edge are all documented players of the unit². That player pedigree, along with the small production run, is a large part of why the FA-1 commands attention on the used market decades later⁴.

Power and the lack of a jack

The FA-1's power arrangement is the detail most players need to know before buying one. Power is supplied exclusively via an internal 9-volt battery, because the original vintage design lacks an external power jack¹. There is no 9V DC input to connect to a pedalboard power supply, so the pedal cannot be daisy-chained or run off a mains adapter as shipped. The current draw is low, at 2.5mA, so a battery lasts a long time, but the always-on architecture means the circuit draws that current whenever a battery is installed¹⁴.

Clones and modern versions

Because original FA-1 units are rare and desirable, several makers have built their own versions of the circuit⁴. JHS Pedals sells the Clover, a take on the FA-1 FET Preamp, and describes the original as one of the two devices Boss launched under the Pocket Series name in early 1984³. In Australia, Audio Blend has evolved the FA-1 preamp into its Edge EQ pedal, keeping the FA-1's Treble and Bass Baxandall controls, Volume with the same +26dB range, and Flat / Low-Cut switch, while adding a parametric EQ section with a PEQ / MID In button and a BAX Out button for switching the Baxandall stage in and out⁶. DIY builders can also find the circuit documented as a project, with madbeanpedals describing the FA-1 as an early '80s "pocket" effect by Boss⁵.

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