125B · 3 knobs
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
Report a wrong parse| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 21 | ||||
| R1 | 1M | 1M | Metal film resistor, 1/4W | |
| R2 | 1M | 1M | Metal film resistor, 1/4W | |
| R3 | 4k7 | 4.7k | Metal film resistor, 1/4W | |
| R4 | 2k2 | 2.2k | Metal film resistor, 1/4W | |
| R5 | 470k | 470k | Metal film resistor, 1/4W | |
| R6 | 4k7 | 4.7k | Metal film resistor, 1/4W | |
| R7 | 220R | 220 | Metal film resistor, 1/4W | |
| R8 | 8k2 | 8.2k | Metal film resistor, 1/4W | |
| R9 | 220k | 220k | Metal film resistor, 1/4W | |
| R10 | 220k | 220k | Metal film resistor, 1/4W | |
| R11 | 1k | 1k | Metal film resistor, 1/4W | |
| R12 | 470R | 470 | Metal film resistor, 1/4W | |
| R13 | 47k | 47k | Metal film resistor, 1/4W | |
| R14 | 47k | 47k | Metal film resistor, 1/4W | |
| R15 | 100k | 100k | Metal film resistor, 1/4W | |
| R16 | 15k | 15k | Metal film resistor, 1/4W | |
| R17 | 1k | 1k | Metal film resistor, 1/4W | |
| R18 | 10k | 10k | Metal film resistor, 1/4W | |
| R19 | 100R | 100 | Metal film resistor, 1/4W | |
| RPD | 2M2 | 2.2M | Metal film resistor, 1/4W | Input pulldown resistor. |
| LEDR | 4k7 | 4.7k | Metal film resistor, 1/4W | LED current-limiting resistor. Adjust value to change LED brightness. |
| Capacitors 12 | ||||
| C1 | 10n | 10n | Film capacitor, 7.2 x 2.5mm | |
| C2 | 4.7uF | 4.7u | Electrolytic capacitor, 4mm | |
| C3 | 100uF | 100u | Electrolytic capacitor, 6.3mm | |
| C4 | 22uF | 22u | Electrolytic capacitor, 5mm | |
| C5 | 4.7uF | 4.7u | Electrolytic capacitor, 4mm | |
| C6 | 4.7uF | 4.7u | Electrolytic capacitor, 4mm | |
| C7 | 1uF | 1u | Film capacitor, 7.2 x 3.5mm | |
| C8 | 1uF | 1u | Film capacitor, 7.2 x 3.5mm | |
| C9 | 1uF | 1u | Film capacitor, 7.2 x 3.5mm | |
| C10 | 1uF | 1u | Film capacitor, 7.2 x 3.5mm | |
| C11 | 100uF | 100u | Electrolytic capacitor, 6.3mm | Power supply filter capacitor. |
| C12 | 100n | 100n | MLCC capacitor, X7R | Power supply filter capacitor. |
| Diodes 3 | ||||
| D1 | 1N5817 | 1N5817 | Schottky diode, DO-41 | |
| D3 | 1N456 | 1N456 | Rectifier diode, DO-35 | |
| D4 | 1N456 | 1N456 | Rectifier diode, DO-35 | |
| Transistors 5 | ||||
| Q1 | MPSA14 | MPSA14 | Darlington transistor, NPN, TO-92 | Substitute. Original uses 2N5306. |
| Q2 | 2N3904 | 2N3904 | BJT transistor, NPN, TO-92 | Substitute. Original uses BC169B. |
| Q3 | MPSA14 | MPSA14 | Darlington transistor, NPN, TO-92 | Substitute. Original uses 2N5306. |
| Q4 | MPSA14 | MPSA14 | Darlington transistor, NPN, TO-92 | Substitute. Original uses 2N5306. |
| Q5 | 2N3904 | 2N3904 | BJT transistor, NPN, TO-92 | |
| Potentiometers 3 | ||||
| TEXT. | 10kB | B10k | 16mm right-angle PCB mount pot | |
| BAL. | 50kB | B50k | 16mm right-angle PCB mount pot | |
| VOL. | 50kB | B50k | 16mm right-angle PCB mount pot | |
| Trimmers 1 | ||||
| OCT. | 10k | 10k | Trimmer, 10%, 1/4" | Set to about 40% rotation (11:00) for stock circuit. |
| Switches 2 | ||||
| BOOST DPDT | Toggle switch, DPDT | TOGGLE SWITCH, DPDT | ||
| FSW | 3PDT | 3PDT | Stomp switch, 3PDT | Available from Aion FX. |
| 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 | Lumberg NEB/J 21 C 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. |
Other boards based on the Ampeg Scrambler
- Ampeg Scrambler Experimentalists Anonymous
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