The Boss FA-1 FET Amplifier is a small preamp pedal from the early 1980s, part of the company's Pocket Series of compact effects. It is a preamp and booster designed to stay on all the time rather than be switched in and out of the signal. TONEHOME lists the production period as 1983 to 1984, so original units are scarce today.12
What it does
The FA-1 is a FET (field-effect transistor) amplifier stage that shapes and boosts the signal on its way to an amp. RockBoard's PedalPedia notes that "the unit relies on an always-on architecture," meaning there is no footswitch to turn it off: it is part of the signal chain permanently.1
That design comes from how Boss intended it to be used. As Madbean Pedals' project document explains, "It had no bypass feature and was meant to work in tandem with MA-1 (a pocket amplifier) or clipped onto a guitar strap." In other words, it was a companion piece for Boss's MA-1 Mascot Amplifier, a tiny amp the FA-1 could feed, and its small size let it ride on a strap rather than a pedalboard.3
The circuit
The original FA-1 ran on a Hitachi op-amp chip. Guitar Pedal X, writing about the circuit's legacy, notes "the original NOS Hitachi HA1457W OpAmp chips featured in the original." That chip is long out of production, which matters to anyone servicing a vintage unit or building a replica.4
"Most takes on the FA-1 rather feature the LM1458."
The LM1458 is a common, inexpensive dual op-amp, which is why most modern builds and clones of the FA-1 circuit use it instead of the scarce Hitachi part. Players comparing an original to a reissue or clone are, in circuit terms, comparing those two chips.4
Buying a vintage FA-1
The FA-1 was discontinued after its short 1983 to 1984 run, and it has never been reissued by Boss in its original form. Madbean Pedals noted in 2020 that "Current prices on Reverb for the vintage units are in the $300-400 range."23
The FA-1 has no bypass, so a vintage unit is always in the circuit when connected. Plan your pedalboard around that, or use it with a loop switcher if you want it out of the signal.
Boss has since revisited the FA-1 concept in other pedals, and the modern Boss FA-1 FET Amplifier and BOSS FA-1 FET Amp pages cover current takes on the design.
Videos
TheSuperFunAwesomeHappyTimePedalShow
Guy Capuano
Cameron Johnson
Sources (4)
- FET Amplifier FA-1 by BOSS, RockBoard PedalPedia, 2026
- TONEHOME, TONEHOME
- Fireaxe.pdf, madbeanpedals.com, 2020
- Guitar Pedal X, Guitar Pedal X, 2024-07-09
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