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125B · 4 knobs

Aion FX

AphelionVintage Distortion

Based on the MXR Distortion+· 2 other boards clone it

Category
Distortion· Overdrive / Distortion
Controls
Gain · Volume · Treble · Clip
Difficulty
Beginner
Price
$12.50in stock

From the vendor

One of the first drive pedals to use an op-amp, this classic effect was a favorite of Yngwie Malmsteen, Thom Yorke and Randy Rhoads among many more.

The Aphelion Vintage Distortion is a clone of the MXR Distortion+, one of the first op-amp-based drive pedals dating all the way back to 1973.

This was also one of the first circuits to use hard diode-to-ground clipping, and while it’s a fairly simple circuit, it served as an ancestor to many other classic pedals like the Boss DS-1 and Maxon/Ibanez SD-9. It has no tone control, but instead, the gain control also changes the tone as you turn it up. Technically speaking, only the bass frequency is cut, but this has the perceived effect of increasing treble as well.

DOD released their version in a few years later in 1976, which they called the Overdrive Preamp 250 (commonly abbreviated to just the “250”). Both versions are classics in their own right, with the Distortion+ being favored by Randy Rhoads, Jerry Garcia, and Thom Yorke, while the 250 is inseparably associated with Yngwie Malmsteen.

Like the Big Muff, both the Distortion+ and 250 had a lot of circuit tweaks throughout the manufacturing run. Because of this, there’s no definitive version of either of them, although some variants were more notable than others. This project includes a versions spreadsheet that provides part values for each of the variants.

The Aphelion adds two extra modifications to the classic two-knob circuit: a treble-cut switch that changes out a capacitor at the input, and a diode selector that lets you go between germanium (Distortion+), silicon (250), or LEDs.

Schematic

The schematic is in the vendor's build document, page 7. Open the build document. No KiCad fragment has been drawn for this circuit yet.

Parts list 32 rows

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RefValueNormalizedTypeNotes
Resistors 8
R110k10k
R21M1M
R31M1M
R44k74.7k
R510k10k
R61M1M
R71M1M
R8100R100
Capacitors 11
C11n1n
C22n22.2n
C32n22.2n
C410n10n
C510pF10p
C647n47n
C71uF1u
C81n1n
C947uF47u
C10100uF100u
C11100n100n
Diodes 9
D11N58171N5817
D2GeGE
D3GeGE
D41N9141N914
D5(jumper(JUMPER
D6(jumper)(JUMPER)
D71N9141N914
D85mm5MM
D95mm5MM
ICs 1
IC1LM741LM741
Potentiometers 3
GAIN500KCC500kPotentiometer
VOL.50KAA50kPotentiometer
ENC125BB125Potentiometer

Other boards based on the MXR Distortion+