125B · 4 knobs
ObeliskVintage Drive
Based on the Lovetone Brown Source
- Category
- Overdrive
- Controls
- Drive · Tone · Volume · Mode
- Difficulty
- Intermediate
- Price
- $12.50in stock
From the vendor
An op-amp overdrive voiced to achieve the legendary “brown sound” tone of the 1960s and 70s, notably used by James Hetfield, Kirk Hammett and Johnny Marr among others.
The Obelisk Vintage Drive is an adaptation of the Lovetone Brown Source, a distortion/overdrive pedal that was first released in 1995, and which also forms the second half of the Cheese Source dual pedal that came later in 1999.
The Brown Source was intended to capture the “brown sound” guitar tone tones from the 1960s and 70s. At first glance it’s a fairly simple diode clipper, but as usual it has a generous dose of Lovetone’s secret sauce for tone-shaping.
As in other Lovetone circuits, it uses a 4-position rotary control for three different parameters: tone control frequency, tonestack bypass, and a treble cut at the end of the circuit that “warms up” the tone and provides a midrange emphasis.
While each of these parameters could be given their own toggle, we found that there were not really any useful sounds to be had in these extra modes and it really worked best with just the four positions of the original. A daughterboard for the rotary switch is included for easy wiring.
Special thanks to Ian (LaceSensor / Gigahearts FX), the DIY community’s resident Lovetone expert, for help verifying the Obelisk prototype against an original Brown Source for accuracy.
Schematic
The schematic is in the vendor's build document, page 8. Open the build document. No KiCad fragment has been drawn for this circuit yet.
Parts list 46 rows
Report a wrong parse| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 16 | ||||
| R1 | 1M2 | 1.2M | Metal film resistor, 1/4W | |
| R2 | 1M2 | 1.2M | Metal film resistor, 1/4W | |
| R3 | 3k9 | 3.9k | Metal film resistor, 1/4W | |
| R4 | 220R | 220 | Metal film resistor, 1/4W | |
| R5 | 1k | 1k | Metal film resistor, 1/4W | |
| R7 | 3k9 | 3.9k | Metal film resistor, 1/4W | |
| R8 | 3k9 | 3.9k | Metal film resistor, 1/4W | |
| R9 | 1M2 | 1.2M | Metal film resistor, 1/4W | Early version uses 330k. See build notes. |
| R10 | 22k | 22k | Metal film resistor, 1/4W | Early version uses 18k. See build notes. |
| R11 | 3k9 | 3.9k | Metal film resistor, 1/4W | |
| R12 | 220R | 220 | Metal film resistor, 1/4W | |
| R13 | 22k | 22k | Metal film resistor, 1/4W | |
| R14 | 22k | 22k | Metal film resistor, 1/4W | |
| R15 | 100R | 100 | Metal film resistor, 1/4W | Power supply filter resistor. |
| LEDR | 4k7 | 4.7k | Metal film resistor, 1/4W | LED current-limiting resistor. Adjust value to change LED brightness. |
| RPD | 2M2 | 2.2M | Metal film resistor, 1/4W | Input pulldown resistor. Can be as low as 1M. |
| Capacitors 14 | ||||
| C1 | 33n | 33n | Film capacitor, 7.2 x 2.5mm | |
| C2 | 470n | 470n | Film capacitor, 7.2 x 3mm | |
| C3 | 33n | 33n | Film capacitor, 7.2 x 2.5mm | |
| C4 | 2.2uF | 2.2u | Film capacitor, 7.2 x 5mm | Can also use 1uF with no change in tone. |
| C5 | 33n | 33n | Film capacitor, 7.2 x 2.5mm | |
| C6 | 220n | 220n | Film capacitor, 7.2 x 2.5mm | |
| C7 | 33n | 33n | Film capacitor, 7.2 x 2.5mm | |
| C8 | 33n | 33n | Film capacitor, 7.2 x 2.5mm | |
| C9 | 220n | 220n | Film capacitor, 7.2 x 2.5mm | |
| C10 | 2.2uF | 2.2u | Film capacitor, 7.2 x 5mm | Can also use 1uF with no change in tone. |
| C11 | 33n | 33n | Film capacitor, 7.2 x 2.5mm | |
| C12 | 47uF | 47u | Electrolytic capacitor, 5mm | Reference voltage filter capacitor. |
| C13 | 100uF | 100u | Electrolytic capacitor, 6.3mm | Power supply filter capacitor. |
| C14 | 100n | 100n | MLCC capacitor, X7R | Power supply filter capacitor. |
| Diodes 3 | ||||
| D1 | 1N5817 | 1N5817 | Schottky diode, DO-41 | |
| D2 | 1N914 | 1N914 | Fast-switching diode, DO-35 | |
| D3 | 1N914 | 1N914 | Fast-switching diode, DO-35 | |
| Transistors 1 | ||||
| Q1 | BC549C | BC549C | BJT transistor, NPN, TO-92 | |
| ICs 1 | ||||
| IC1 | TL072 | TL072 | Operational amplifier, DIP8 | |
| Potentiometers 3 | ||||
| DRIVE | 25kB | B25k | 16mm right-angle PCB mount pot | Can substitute 50kB or 100kB for more available drive. |
| TONE | 100kB | B100k | 16mm right-angle PCB mount pot | |
| VOL. | 10kA | A10k | 16mm right-angle PCB mount pot | |
| Switches 2 | ||||
| MODE | 3P4T rotary | 3P4T ROTARY | Rotary switch, 3 pole / 4 position | Must be Alpha SR2612F. See parts spreadsheet (2nd tab) for sources. |
| FSW | 3PDT | 3PDT | Stomp switch, 3PDT | |
| LEDs 1 | ||||
| LED | 5mm | 5MM | LED, 5mm, red diffused | |
| Jacks & sockets 4 | ||||
| IC1-S | DIP8 socket | DIP8 SOCKET | IC socket, DIP-8 | |
| IN | 1/4" mono | 1/4" MONO | 1/4" phone jack, closed frame | Switchcraft 111X 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. |