Akashic Guitar effects PCB lookup
DRIVETONEVOLUMEMODE

125B · 4 knobs

Aion FX

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

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RefValueNormalizedTypeNotes
Resistors 16
R11M21.2MMetal film resistor, 1/4W
R21M21.2MMetal film resistor, 1/4W
R33k93.9kMetal film resistor, 1/4W
R4220R220Metal film resistor, 1/4W
R51k1kMetal film resistor, 1/4W
R73k93.9kMetal film resistor, 1/4W
R83k93.9kMetal film resistor, 1/4W
R91M21.2MMetal film resistor, 1/4WEarly version uses 330k. See build notes.
R1022k22kMetal film resistor, 1/4WEarly version uses 18k. See build notes.
R113k93.9kMetal film resistor, 1/4W
R12220R220Metal film resistor, 1/4W
R1322k22kMetal film resistor, 1/4W
R1422k22kMetal film resistor, 1/4W
R15100R100Metal film resistor, 1/4WPower supply filter resistor.
LEDR4k74.7kMetal film resistor, 1/4WLED current-limiting resistor. Adjust value to change LED brightness.
RPD2M22.2MMetal film resistor, 1/4WInput pulldown resistor. Can be as low as 1M.
Capacitors 14
C133n33nFilm capacitor, 7.2 x 2.5mm
C2470n470nFilm capacitor, 7.2 x 3mm
C333n33nFilm capacitor, 7.2 x 2.5mm
C42.2uF2.2uFilm capacitor, 7.2 x 5mmCan also use 1uF with no change in tone.
C533n33nFilm capacitor, 7.2 x 2.5mm
C6220n220nFilm capacitor, 7.2 x 2.5mm
C733n33nFilm capacitor, 7.2 x 2.5mm
C833n33nFilm capacitor, 7.2 x 2.5mm
C9220n220nFilm capacitor, 7.2 x 2.5mm
C102.2uF2.2uFilm capacitor, 7.2 x 5mmCan also use 1uF with no change in tone.
C1133n33nFilm capacitor, 7.2 x 2.5mm
C1247uF47uElectrolytic capacitor, 5mmReference voltage filter capacitor.
C13100uF100uElectrolytic capacitor, 6.3mmPower supply filter capacitor.
C14100n100nMLCC capacitor, X7RPower supply filter capacitor.
Diodes 3
D11N58171N5817Schottky diode, DO-41
D21N9141N914Fast-switching diode, DO-35
D31N9141N914Fast-switching diode, DO-35
Transistors 1
Q1BC549CBC549CBJT transistor, NPN, TO-92
ICs 1
IC1TL072TL072Operational amplifier, DIP8
Potentiometers 3
DRIVE25kBB25k16mm right-angle PCB mount potCan substitute 50kB or 100kB for more available drive.
TONE100kBB100k16mm right-angle PCB mount pot
VOL.10kAA10k16mm right-angle PCB mount pot
Switches 2
MODE3P4T rotary3P4T ROTARYRotary switch, 3 pole / 4 positionMust be Alpha SR2612F. See parts spreadsheet (2nd tab) for sources.
FSW3PDT3PDTStomp switch, 3PDT
LEDs 1
LED5mm5MMLED, 5mm, red diffused
Jacks & sockets 4
IC1-SDIP8 socketDIP8 SOCKETIC socket, DIP-8
IN1/4" mono1/4" MONO1/4" phone jack, closed frameSwitchcraft 111X 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.