Boss FA-1

A clean boost pedal that is used by U2 guitarist “The Edge”.
This is a work-alike circuit as the original op-amps and FET are hard to come by.
I used a 4558 for the IC and a J201 for the FET.
Note that the 47uF cap is non-polar.

Download Build Diagram and Etch Template
Download Schematic

FA-1 Thumbnail

7 Responses to “Boss FA-1”

  1. Gerrit Koerselman Says:

    Nice PCB layout!

    I’ve seen that small bear carries the HA1457W and 2SK246-GR. Do you think it would be worth to get them? I’m in Germany so shipping would be at a bit of a cost.

    I also saw that you are using only one 4558 (dual opamp) where the original uses 2 HA1457Ws. Are C13 and C14 (both 100p caps) not required for the 4558?

    Oh yeah, would you share your ‘eagle’ schematic with me?


  2. Immo Says:


    you´ve got some really good Layouts here!

    But is it true that there´s a 47µF non polar Cap in the circuit?
    The original schematics says “0.47µF.
    I can´t find a non-polar 47µF that would fit in there – they´re all too big and have axial leads.


  3. ralph Says:

    … and if I understand that circuit, the 47µF non-polar cap wouldn´t make any sense! I think a 0.47µF film cap should do the job.
    Would be nice to read what you think about that!

    Or has anybody else built the FA-1?

  4. Remco Says:

    Yeah, it needs to be a 0.47uF Non-Polar electolytic.
    I traced the original PCB part for part, after owning an original FA-1.

    I made a clone, after managing to find the last 2 HA1457W’s locally (paid almost 9 euro a piece for them!) and that little shop (now out of business) also had 3 correct 2SK246-GR FET’s around.

  5. Fernando Says:

    I’ve just built this one using a 470n instead of the “47u NP”. It works great with the recommended IC and FeT. Thanks for the layout.

  6. JD Says:

    The greatest thing about my Boss FA-1 was the extremely high output: it could directly drive any power amp to clipping with no strain. Does this single-IC version have that much gain and output?

  7. Hanhoo Says:

    I just finished the build using exactly the above schematic and PCB layout, but i’m getting a huge amount of noise on the input side. The noise timbre changes when I turn the volume on my guitar. The noise followes the volume nob on the FA-1 clone. The noise (naturally) goes away when I hit the bypass switch. I double checked all the components and can’t find anything wrong.

    Any hint on what’s causing this noise?

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