Akashic Guitar effects PCB lookup
TREBLEBASSVOLUME

1590B · 3 knobs

Aion FX

Prism (Legacy)

Based on the BOSS FA-1 FET Amplifier· 2 other boards clone it

Category
Boost· Boost / Preamplifier
Controls
Treble · Bass · Volume
Difficulty
Easy
Price
see vendor

From the vendor

An extremely loud and tonally-flexible boost/preamp with a two-band EQ, most notably used by The Edge of U2.

These things have recently gotten a lot of attention since someone found out that The Edge from U2 uses one as part of his sound. Originals routinely sell for over $500 on eBay.

The Boss FA-1 FET Amplifier was released in the early 80’s and discontinued in 1985. The original was not a traditional pedal, but instead an always-on effect with a clip on the back, with the idea that you actually wore it and your guitar plugged straight into it before going to the rest of your chain.

My version adds a footswitch and LED to turn it into an actual effect that’s more at home on the floor than clipped to your belt. Otherwise, it is completely faithful to the original circuit. If you’d like to experiment, it also has additional pads allowing you to use a DIP8 dual opamp instead of two stock SIL HA1457Ws as in the original. (I recommend the LM1458 as a great alternative to two HA1457s. I couldn’t hear the difference in an A/B test.)

If you want to read more about this pedal, Music Gear Reviews has a fantastic article.

Schematic

The schematic is in the vendor's build document, page 3. Open the build document. No KiCad fragment has been drawn for this circuit yet.

Parts list 39 rows

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RefValueNormalizedTypeNotes
Resistors 15
R110k10k
R23M33.3M
R310k10k
R4470k470k
R515k15k
R6470k470k
R78k28.2k
R833k33k
R98k28.2k
R1010k10k
R11470R470
R12100k100k
R1322k22k
R146k86.8k
R1515k15k
Capacitors 14
C110n10n
C2470n470n
C347n47n
C410uF10u
C510uF10u
C633n33n
C733n33n
C85n65.6n
C95n65.6n
C1010uF10u
C1110uF10u
C12100uF100u
C13100pF100p
C14100pF100p
Diodes 1
D11N40021N4002
Transistors 1
Q12SK2462SK246
ICs 2
IC1HA1457WHA1457W
IC2HA1457WHA1457W
Potentiometers 4
TREBLE50KBB50kPotentiometer
BASS50KBB50kPotentiometer
VOLUME1MAA1MPotentiometer
RPD1M1MPotentiometer
Switches 1
SW1SPDTSPDT
LEDs 1
LED1intoINTO

Other boards based on the BOSS FA-1 FET Amplifier