Boss FA-1 Project…Getting Started

Posted: 2009/05/27 in Boss FA-1 Clone, DIY Guitar Effect Pedal Projects

O.K. So what is the Boss FA-1?  Well here are some pictures of one in nearly mint condition with the box (no, not mine):


As you can see it’s not really even a proper pedal… there is no footswitch.  Interestingly, it has a clip on the back in order to attach it to your belt.  (I know of at least one other pedal in this “pocket series” by Boss.  There was also a pedal called the MA-1  also with a belt clip that has a little speaker in it!)

fa-1 in boss book

I suppose the purpose of this could have been to have a buffer/line  driver close your guitar in order to drive long cables without losing high end due to cable capacitance.   It turns out that the simple circuit of the FA-1 also makes a good volume boost pedal for solos, etc… Well, at least we know The Edge thinks so since he has had one in his rack for years.

Let’s take a look at the schematic:

FA-1 Schematic

FA-1 Schematic

Following the circuit from the input there is a basic FET buffer circuit, a switchable low-cut (high-pass) filter, followed by two inverting op amp stages, the first giving volume amplification, and the second with a a Baxandall tone circuit in the feedback loop giving treble/bass control.  (More about this here .) The name “FET Amplifier” is perhaps a little misleading since the FET circuit is only a unity gain buffer and the amplification is done by op amps (HA1457…which don’t even have any FETs inside them).

  1. Rik Smith says:

    I found an ORIGIANAL Boss FA-1 FET Amplifier,complete like new box,with manual,boss battery.This thing has the new smell,not 1 scratch,absolutely mint.Found it at a thrift shop for $7.99.I had no idea of its value at the time.

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