Akashic Guitar effects PCB lookup
PREAMPPRESENCEFULLNESSMASTER

125B · 4 knobs

Aion FX

Triton Mk. IIPreamp Drive

Based on the Dirty Little Secret Mk. II

Category
Overdrive· Overdrive / Amp Emulation
Controls
Preamp · Presence · Fullness · Master
Difficulty
Intermediate
Price
$12.50in stock

From the vendor

An adaptation of the classic Marshall amplifiers from the 1960s. It uses cascaded mu-amp stages in place of tubes for amp-like tone in a small box.

The Triton Preamp Drive Mk. II is an adaptation of the Catalinbread Dirty Little Secret Mk. II, the second version of their pedal emulation of Marshall amplifiers. It was originally released in 2011 and was traced by Aion FX in 2020.

The DLS Mk. II is a fair amount different from both the Mk. I and the Mk. III. It didn’t get as much attention on its own, probably partially due to the confusing tone stack labeled “Fullness” and “Presence” rather than the more familiar Bass and Treble

In 2013, it was replaced by the Dirty Little Secret Mk. III, a full redesign which is still in production today. A PCB for this version is available from Aion FX as the Triton Mk. III. The original version of the Dirty Little Secret is also available as the Horizon.

The Dirty Little Secret used 2N5457 JFETs, which are no longer available in through-hole format. Extra pads have been provided if you want to use surface-mount JFETs (part number MMBF5457), which are still in production and perform identically to those used in Catalinbread pedals. Aion FX also offers pre-soldered MMBF5457s on adapter boards if you find surface-mount parts intimidating. See project documentation for more details.

The Triton Mk. II is compatible with the 18V Voltage Doubler / Bypass module if you want to run the circuit at 18V without an external adapter. The higher voltage provides increased volume and clarity.

Note: This project uses a type of capacitor that has been temporarily discontinued by WIMA. Please see our news article about the issue and the substitution spreadsheet for project-specific recommendations. The build document has not yet been updated to reflect this.

Schematic

The schematic is in the vendor's build document, page 6. Open the build document. No KiCad fragment has been drawn for this circuit yet.

Parts list 58 rows

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RefValueNormalizedTypeNotes
Resistors 22
R1470k470kMetal film resistor, 1/4W
R233k33kMetal film resistor, 1/4W
R32M22.2MMetal film resistor, 1/4W
R41k1kMetal film resistor, 1/4W
R51M1MMetal film resistor, 1/4W
R61M1MMetal film resistor, 1/4W
R747k47kMetal film resistor, 1/4W
R8470k470kMetal film resistor, 1/4W
R9470k470kMetal film resistor, 1/4W
R101k1kMetal film resistor, 1/4W
R111M1MMetal film resistor, 1/4W
R121M1MMetal film resistor, 1/4W
R13130R130Metal film resistor, 1/4W
R1433k33kMetal film resistor, 1/4W
R1522k22kMetal film resistor, 1/4W
R163k33.3kMetal film resistor, 1/4W
R172M22.2MMetal film resistor, 1/4W
R182M2MMetal film resistor, 1/4W
R194k74.7kMetal film resistor, 1/4W
R202k2kMetal film resistor, 1/4W
R21100R100Metal film resistor, 1/4W
LEDR4k74.7kMetal film resistor, 1/4WLED current-limiting resistor. Adjust value to change LED brightness.
Capacitors 21
C1220n220nFilm capacitor, 7.2 x 2.5mm
C21n1nFilm capacitor, 7.2 x 2.5mm
C3220n220nFilm capacitor, 7.2 x 2.5mm
C4680n680nFilm capacitor, 7.2 x 4.5mm
C52.2uF2.2uFilm capacitor, 7.2 x 5mmCan also substitute electrolytic (polarity marked on PCB)
C6470pF470pMLCC capacitor, NP0/C0G
C722n22nFilm capacitor, 7.2 x 2.5mm
C8100pF100pMLCC capacitor, NP0/C0G
C9470pF470pMLCC capacitor, NP0/C0G
C10470pF470pMLCC capacitor, NP0/C0G
C11680n680nFilm capacitor, 7.2 x 4.5mm
C122.2uF2.2uFilm capacitor, 7.2 x 5mmCan also substitute electrolytic (polarity marked on PCB)
C13470pF470pMLCC capacitor, NP0/C0G
C14470pF470pMLCC capacitor, NP0/C0G
C1522n22nFilm capacitor, 7.2 x 2.5mm
C1622n22nFilm capacitor, 7.2 x 2.5mm
C17100n100nFilm capacitor, 7.2 x 2.5mm
C18220n220nFilm capacitor, 7.2 x 2.5mm
C1922n22nFilm capacitor, 7.2 x 2.5mm
C20100uF100uElectrolytic capacitor, 6.3mmPower supply filter capacitor.
C21100n100nMLCC capacitor, X7RPower supply filter capacitor.
Diodes 1
D11N58171N5817Schottky diode, DO-41
Transistors 5
Q1MMBF5457MMBF5457JFET, N-channel, SOT-23Substitute for 2N5457 (TO-92). See build notes.
Q2MMBF5457MMBF5457JFET, N-channel, SOT-23Substitute for 2N5457 (TO-92). See build notes.
Q3MMBF5457MMBF5457JFET, N-channel, SOT-23Substitute for 2N5457 (TO-92). See build notes.
Q4MMBF5457MMBF5457JFET, N-channel, SOT-23Substitute for 2N5457 (TO-92). See build notes.
Q5MMBF5457MMBF5457JFET, N-channel, SOT-23Substitute for 2N5457 (TO-92). See build notes.
Potentiometers 4
PRE.1MAA1M16mm right-angle PCB mount pot
FULL.1MAA1M16mm right-angle PCB mount pot
PRES.250kBB250k16mm right-angle PCB mount pot
MAST.250kAA250k16mm right-angle PCB mount pot
Switches 1
FSW3PDT3PDTStomp switch, 3PDT
Jacks & sockets 3
IN1/4" stereo1/4" STEREO1/4" phone jack, closed frameSwitchcraft 112BX or equivalent.
OUT1/4" mono1/4" MONO1/4" phone jack, closed frameSwitchcraft 111X or equivalent.
DC2.1mm2.1MMDC jack, 2.1mm panel mountMouser 163-4302-E or equivalent.
Hardware 1
ENC125B125BEnclosure, die-cast aluminumCan also use a Hammond 1590N1.