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TEXTUREBLENDVOLUME

125B · 3 knobs

Aion FX

ApertureOctave Fuzz

Based on the Ampeg Scrambler· 3 other boards clone it

Category
Fuzz· Octave-up fuzz
Controls
Texture · Blend · Volume
Difficulty
Easy
Price
$12.50in stock

From the vendor

A legendary octave-up fuzz effect with a blend control that makes it great for bass guitar.

The Aperture Octave Fuzz is an adaptation of the Ampeg Scrambler, an exceptionally rare octave-up fuzz pedal originally released in 1969. It’s said that fewer than 2,500 units were produced, and today the originals typically sell for over USD$1,000 on the used market.

The Scrambler is an octave-up fuzz in the vein of the Superfuzz, fOXX Tone Machine and Octavia—although all four circuits use their own techniques to generate the octave, so they all sound different.

Due to its largely un-filtered bass content and clean blend control, the Scrambler is particularly good for bass guitar, as you would expect from a company that primarily makes bass equipment.

Ampeg reissued the Scrambler in 2005 in a vintage-style enclosure. According to Analogman, these reissues are very faithful to the originals, but not identical.

In 2017, the Scrambler was again reissued, this time in a modernized enclosure and including a treble control and output volume, and marketed as a “bass overdrive” with no mention of fuzz. It’s not known how accurate these circuits are to the original, but they have received mixed reviews and are not regarded to sound like either the old ones or the 2005 reissues, so it is likely that the resemblance is in name only.

The Aperture project is faithful to the original 1969 Scrambler, with the addition of an optional volume boost stage as well as a master volume control at the end. The original unit suffers from excessively low volume, so the make-up gain stage from the Univox Superfuzz has been adapted for this circuit. With the gain boost disabled and the Volume knob at full, the circuit is 100% identical to a vintage Scrambler.

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 5. Open the build document. No KiCad fragment has been drawn for this circuit yet.

Parts list 53 rows

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Resistors 21
R11M1MMetal film resistor, 1/4W
R21M1MMetal film resistor, 1/4W
R34k74.7kMetal film resistor, 1/4W
R42k22.2kMetal film resistor, 1/4W
R5470k470kMetal film resistor, 1/4W
R64k74.7kMetal film resistor, 1/4W
R7220R220Metal film resistor, 1/4W
R88k28.2kMetal film resistor, 1/4W
R9220k220kMetal film resistor, 1/4W
R10220k220kMetal film resistor, 1/4W
R111k1kMetal film resistor, 1/4W
R12470R470Metal film resistor, 1/4W
R1347k47kMetal film resistor, 1/4W
R1447k47kMetal film resistor, 1/4W
R15100k100kMetal film resistor, 1/4W
R1615k15kMetal film resistor, 1/4W
R171k1kMetal film resistor, 1/4W
R1810k10kMetal film resistor, 1/4W
R19100R100Metal film resistor, 1/4W
RPD2M22.2MMetal film resistor, 1/4WInput pulldown resistor.
LEDR4k74.7kMetal film resistor, 1/4WLED current-limiting resistor. Adjust value to change LED brightness.
Capacitors 12
C110n10nFilm capacitor, 7.2 x 2.5mm
C24.7uF4.7uElectrolytic capacitor, 4mm
C3100uF100uElectrolytic capacitor, 6.3mm
C422uF22uElectrolytic capacitor, 5mm
C54.7uF4.7uElectrolytic capacitor, 4mm
C64.7uF4.7uElectrolytic capacitor, 4mm
C71uF1uFilm capacitor, 7.2 x 3.5mm
C81uF1uFilm capacitor, 7.2 x 3.5mm
C91uF1uFilm capacitor, 7.2 x 3.5mm
C101uF1uFilm capacitor, 7.2 x 3.5mm
C11100uF100uElectrolytic capacitor, 6.3mmPower supply filter capacitor.
C12100n100nMLCC capacitor, X7RPower supply filter capacitor.
Diodes 3
D11N58171N5817Schottky diode, DO-41
D31N4561N456Rectifier diode, DO-35
D41N4561N456Rectifier diode, DO-35
Transistors 5
Q1MPSA14MPSA14Darlington transistor, NPN, TO-92Substitute. Original uses 2N5306.
Q22N39042N3904BJT transistor, NPN, TO-92Substitute. Original uses BC169B.
Q3MPSA14MPSA14Darlington transistor, NPN, TO-92Substitute. Original uses 2N5306.
Q4MPSA14MPSA14Darlington transistor, NPN, TO-92Substitute. Original uses 2N5306.
Q52N39042N3904BJT transistor, NPN, TO-92
Potentiometers 3
TEXT.10kBB10k16mm right-angle PCB mount pot
BAL.50kBB50k16mm right-angle PCB mount pot
VOL.50kBB50k16mm right-angle PCB mount pot
Trimmers 1
OCT.10k10kTrimmer, 10%, 1/4"Set to about 40% rotation (11:00) for stock circuit.
Switches 2
BOOST DPDTToggle switch, DPDTTOGGLE SWITCH, DPDT
FSW3PDT3PDTStomp switch, 3PDTAvailable from Aion FX.
LEDs 1
LED5mm5MMLED, 5mm, red diffused
Jacks & sockets 3
IN1/4" stereo1/4" STEREO1/4" phone jack, closed frameSwitchcraft 112BX or equivalent.
OUT1/4" mono1/4" MONO1/4" phone jack, closed frameSwitchcraft 111X or equivalent.
DC2.1mm2.1MMDC jack, 2.1mm panel mountLumberg NEB/J 21 C or equivalent.
Hardware 2
BATTBattery snapBATTERY SNAP9V battery snapOptional. Use the soft plastic type—the hard-shell type will not fit.
ENC125B125BEnclosure, die-cast aluminumCan also use a Hammond 1590N1.

Other boards based on the Ampeg Scrambler