125B · 4 knobs
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
Report a wrong parse| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 22 | ||||
| R1 | 470k | 470k | Metal film resistor, 1/4W | |
| R2 | 33k | 33k | Metal film resistor, 1/4W | |
| R3 | 2M2 | 2.2M | Metal film resistor, 1/4W | |
| R4 | 1k | 1k | Metal film resistor, 1/4W | |
| R5 | 1M | 1M | Metal film resistor, 1/4W | |
| R6 | 1M | 1M | Metal film resistor, 1/4W | |
| R7 | 47k | 47k | Metal film resistor, 1/4W | |
| R8 | 470k | 470k | Metal film resistor, 1/4W | |
| R9 | 470k | 470k | Metal film resistor, 1/4W | |
| R10 | 1k | 1k | Metal film resistor, 1/4W | |
| R11 | 1M | 1M | Metal film resistor, 1/4W | |
| R12 | 1M | 1M | Metal film resistor, 1/4W | |
| R13 | 130R | 130 | Metal film resistor, 1/4W | |
| R14 | 33k | 33k | Metal film resistor, 1/4W | |
| R15 | 22k | 22k | Metal film resistor, 1/4W | |
| R16 | 3k3 | 3.3k | Metal film resistor, 1/4W | |
| R17 | 2M2 | 2.2M | Metal film resistor, 1/4W | |
| R18 | 2M | 2M | Metal film resistor, 1/4W | |
| R19 | 4k7 | 4.7k | Metal film resistor, 1/4W | |
| R20 | 2k | 2k | Metal film resistor, 1/4W | |
| R21 | 100R | 100 | Metal film resistor, 1/4W | |
| LEDR | 4k7 | 4.7k | Metal film resistor, 1/4W | LED current-limiting resistor. Adjust value to change LED brightness. |
| Capacitors 21 | ||||
| C1 | 220n | 220n | Film capacitor, 7.2 x 2.5mm | |
| C2 | 1n | 1n | Film capacitor, 7.2 x 2.5mm | |
| C3 | 220n | 220n | Film capacitor, 7.2 x 2.5mm | |
| C4 | 680n | 680n | Film capacitor, 7.2 x 4.5mm | |
| C5 | 2.2uF | 2.2u | Film capacitor, 7.2 x 5mm | Can also substitute electrolytic (polarity marked on PCB) |
| C6 | 470pF | 470p | MLCC capacitor, NP0/C0G | |
| C7 | 22n | 22n | Film capacitor, 7.2 x 2.5mm | |
| C8 | 100pF | 100p | MLCC capacitor, NP0/C0G | |
| C9 | 470pF | 470p | MLCC capacitor, NP0/C0G | |
| C10 | 470pF | 470p | MLCC capacitor, NP0/C0G | |
| C11 | 680n | 680n | Film capacitor, 7.2 x 4.5mm | |
| C12 | 2.2uF | 2.2u | Film capacitor, 7.2 x 5mm | Can also substitute electrolytic (polarity marked on PCB) |
| C13 | 470pF | 470p | MLCC capacitor, NP0/C0G | |
| C14 | 470pF | 470p | MLCC capacitor, NP0/C0G | |
| C15 | 22n | 22n | Film capacitor, 7.2 x 2.5mm | |
| C16 | 22n | 22n | Film capacitor, 7.2 x 2.5mm | |
| C17 | 100n | 100n | Film capacitor, 7.2 x 2.5mm | |
| C18 | 220n | 220n | Film capacitor, 7.2 x 2.5mm | |
| C19 | 22n | 22n | Film capacitor, 7.2 x 2.5mm | |
| C20 | 100uF | 100u | Electrolytic capacitor, 6.3mm | Power supply filter capacitor. |
| C21 | 100n | 100n | MLCC capacitor, X7R | Power supply filter capacitor. |
| Diodes 1 | ||||
| D1 | 1N5817 | 1N5817 | Schottky diode, DO-41 | |
| Transistors 5 | ||||
| Q1 | MMBF5457 | MMBF5457 | JFET, N-channel, SOT-23 | Substitute for 2N5457 (TO-92). See build notes. |
| Q2 | MMBF5457 | MMBF5457 | JFET, N-channel, SOT-23 | Substitute for 2N5457 (TO-92). See build notes. |
| Q3 | MMBF5457 | MMBF5457 | JFET, N-channel, SOT-23 | Substitute for 2N5457 (TO-92). See build notes. |
| Q4 | MMBF5457 | MMBF5457 | JFET, N-channel, SOT-23 | Substitute for 2N5457 (TO-92). See build notes. |
| Q5 | MMBF5457 | MMBF5457 | JFET, N-channel, SOT-23 | Substitute for 2N5457 (TO-92). See build notes. |
| Potentiometers 4 | ||||
| PRE. | 1MA | A1M | 16mm right-angle PCB mount pot | |
| FULL. | 1MA | A1M | 16mm right-angle PCB mount pot | |
| PRES. | 250kB | B250k | 16mm right-angle PCB mount pot | |
| MAST. | 250kA | A250k | 16mm right-angle PCB mount pot | |
| Switches 1 | ||||
| FSW | 3PDT | 3PDT | Stomp switch, 3PDT | |
| Jacks & sockets 3 | ||||
| IN | 1/4" stereo | 1/4" STEREO | 1/4" phone jack, closed frame | Switchcraft 112BX or equivalent. |
| OUT | 1/4" mono | 1/4" MONO | 1/4" phone jack, closed frame | Switchcraft 111X or equivalent. |
| DC | 2.1mm | 2.1MM | DC jack, 2.1mm panel mount | Mouser 163-4302-E or equivalent. |
| Hardware 1 | ||||
| ENC | 125B | 125B | Enclosure, die-cast aluminum | Can also use a Hammond 1590N1. |