125B · 3 knobs
HorizonAmp Overdrive
Based on the Catalinbread DLS Mk.I
- Category
- Overdrive
- Controls
- Gain · Tone · Level
- Difficulty
- Easy
- Price
- $12.50in stock
From the vendor
An “amp in a box” drive pedal inspired by the sounds of 1970s Marshall amplifiers.
The Horizon Amp Overdrive is a recreation of the Catalinbread Dirty Little Secret Mk. I, a unique drive pedal that resembles a Marshall amp stack in its response and tone.
The DLS Mk I was the first of three versions, and is often considered the best—or at least, different enough that subsequent versions should have been released as new pedals. They share some DNA in common, but they have very different tonestacks and tweakability.
The DLS circuit uses cascaded mu-amps as a foundation. There are no op-amps or clipping diodes. The clipping signal is generated entirely by the JFETs, giving it a different flavor than diode-clipping-based overdrives.
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. We are stocking a limited supply in the mean time. 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 56 rows
Report a wrong parse| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 19 | ||||
| R1 | 1M | 1M | Metal film resistor, 1/4W | |
| R2 | 47k | 47k | Metal film resistor, 1/4W | |
| R3 | 10k | 10k | Metal film resistor, 1/4W | |
| R4 | 1M | 1M | Metal film resistor, 1/4W | |
| R5 | 1M | 1M | Metal film resistor, 1/4W | |
| R6 | 4k7 | 4.7k | Metal film resistor, 1/4W | |
| R7 | 470k | 470k | Metal film resistor, 1/4W | |
| R8 | 200k | 200k | Metal film resistor, 1/4W | |
| R9 | 22k | 22k | Metal film resistor, 1/4W | |
| R10 | 470k | 470k | Metal film resistor, 1/4W | |
| R11 | 1M | 1M | Metal film resistor, 1/4W | |
| R12 | 1M | 1M | Metal film resistor, 1/4W | |
| R13 | 1M | 1M | Metal film resistor, 1/4W | |
| R14 | 4k7 | 4.7k | Metal film resistor, 1/4W | |
| R15 | 22k | 22k | Metal film resistor, 1/4W | |
| R16 | 12k | 12k | Metal film resistor, 1/4W | |
| R17 | 200k | 200k | Metal film resistor, 1/4W | |
| R18 | 47R | 47 | 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 19 | ||||
| C1 | 47n | 47n | Film capacitor, 7.2 x 2.5mm | |
| C2 | 100pF | 100p | MLCC capacitor, NP0/C0G | |
| C3 | 220n | 220n | Film capacitor, 7.2 x 2.5mm | |
| C4 | 4.7uF | 4.7u | Electrolytic capacitor, 4mm | |
| C5 | 22n | 22n | Film capacitor, 7.2 x 2.5mm | |
| C6 | 47n | 47n | Film capacitor, 7.2 x 2.5mm | |
| C7 | 470pF | 470p | MLCC capacitor, NP0/C0G | |
| C8 | 200pF | 200p | MLCC capacitor, NP0/C0G | |
| C9 | 47pF | 47p | MLCC capacitor, NP0/C0G | |
| C10 | 220pF | 220p | MLCC capacitor, NP0/C0G | |
| C11 | 4n7 | 4.7n | Film capacitor, 7.2 x 2.5mm | |
| C12 | 47n | 47n | Film capacitor, 7.2 x 2.5mm | |
| C13 | 47pF | 47p | MLCC capacitor, NP0/C0G | |
| C14 | 10uF | 10u | Electrolytic capacitor, 5mm | |
| C15 | 2.2uF | 2.2u | Film capacitor, 7.2 x 5mm | |
| C16 | 33n | 33n | Film capacitor, 7.2 x 2.5mm | |
| C17 | 3n3 | 3.3n | Film capacitor, 7.2 x 2.5mm | |
| C18 | 100n | 100n | MLCC capacitor, X7R | Power supply filter capacitor. |
| C19 | 100uF | 100u | Electrolytic capacitor, 6.3mm | Power supply filter capacitor. |
| Diodes 1 | ||||
| D1 | 1N5817 | 1N5817 | Schottky diode, DO-41 | |
| Transistors 6 | ||||
| Q1 | 2N5457 | 2N5457 | JFET, N-channel, TO-92 | |
| Q2 | 2N5457 | 2N5457 | JFET, N-channel, TO-92 | |
| Q3 | 2N5457 | 2N5457 | JFET, N-channel, TO-92 | |
| Q4 | 2N5457 | 2N5457 | JFET, N-channel, TO-92 | |
| Q5 | 2N5457 | 2N5457 | JFET, N-channel, TO-92 | |
| Q6 | 2N5457 | 2N5457 | JFET, N-channel, TO-92 | |
| Potentiometers 3 | ||||
| GAIN | 1MA | A1M | 16mm right-angle PCB mount pot | |
| TONE | 100kB | B100k | 16mm right-angle PCB mount pot | |
| VOL | 100kB | B100k | 16mm right-angle PCB mount pot | |
| Switches 2 | ||||
| ROCK | DPDT on-on | DPDT ON-ON | Toggle switch, DPDT on-on | |
| FSW | 3PDT | 3PDT | Stomp switch, 3PDT | |
| LEDs 1 | ||||
| LED | 5mm | 5MM | LED, 5mm, red diffused | |
| 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 2 | ||||
| BATT | Battery snap | BATTERY SNAP | 9V battery snap | Optional. Use the soft plastic type—the hard-shell type will not fit. |
| ENC | 125B | 125B | Enclosure, die-cast aluminum | Can also use a Hammond 1590N1. |