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PROJECT NAME
PHOBOS
BASED ON
Tone Bender Mk. III (3-knob)
EFFECT TYPE
Germanium fuzz
PROJECT SUMMARY
A reproduction of the third version of the Tone Bender germanium fuzz sold by Macaris in London in the
late 1960s.
Actual size is 2.3" x 1.86" (main board) and 2.3" x 0.86" (bypass board).
This documentation is for the PCB-only version of the project. If you are building the full kit from
Aion FX, please use the
may differ in some areas due to the specialized parts and assembly methods used in our kits.
PHOBOS GERMANIUM FUZZ
IMPORTANT NOTE
kit build documentation
BUILD DIFFICULTY
Easy
DOCUMENT VERSION
1.0.2 (2024-08-08)
instead. The instructions are more detailed and
1

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Summary of Contents for aion PHOBOS GERMANIUM FUZZ

  • Page 1 Actual size is 2.3” x 1.86” (main board) and 2.3” x 0.86” (bypass board). IMPORTANT NOTE This documentation is for the PCB-only version of the project. If you are building the full kit from Aion FX, please use the kit build documentation instead. The instructions are more detailed and may differ in some areas due to the specialized parts and assembly methods used in our kits.
  • Page 2: Table Of Contents

    11 Document Revisions INTRODUCTION The Phobos Germanium Fuzz is a clone of the Colorsound / Sola Sound Tone Bender Mk III. While the first version was essentially the same topology as a Fuzz Face, and the second version added a gain stage...
  • Page 3: Parts List

    Electrolytic capacitor, 5mm 470n MLCC capacitor, X7R 100n MLCC capacitor, X7R 1N4742A Zener diode, 12V, DO-41 1N5817 Schottky diode, DO-41 Germanium Germanium diode, DO-07 Original uses 1N270, but part number isn’t important. Just use any NOS germanium diode. PHOBOS GERMANIUM FUZZ...
  • Page 4 DC jack, 2.1mm panel mount Mouser 163-4302-E or equivalent. BATT Battery snap 9V battery snap Optional. Use the soft plastic type—the hard-shell type will not fit. 3PDT Stomp switch, 3PDT 125B Enclosure, die-cast aluminum Can also use a Hammond 1590N1. PHOBOS GERMANIUM FUZZ...
  • Page 5: Build Notes

    For Q3, the EQ does change a bit depending on the bias, but as long as the transistors have the right characteristics, the overall character of the fuzz will be the same across the range. PHOBOS GERMANIUM FUZZ...
  • Page 6: Output Volume

    While the circuit isn’t lacking in available volume, if you’d like to get a little more out of it, you can reduce this resistor to 68k and then increase the volume control to 250kA. This gives you the same total resistance (~320k) so the tone and output impedance is unaffected, but available output volume is increased. PHOBOS GERMANIUM FUZZ...
  • Page 7: Schematic

    SCHEMATIC 1N5817 100uF 100n 10uF TC1044SCPA PWR_GND PWR_GND 470n 47uF PWR_GND PWR_GND Q3 BIAS 50kB 220k FUZZ 100kB 220pF 10uF GND GND PHOBOS GERMANIUM FUZZ...
  • Page 8: Drill Template

    INCH 0.625” 0.625” ø3/8” ø3/8” ø1/2” VOLUME FUZZ x: -0.65, y: +1.71 x: 0.65, y: +1.71 ø9/32” ø9/32” TONE x: 0, y: +0.66 ø9/32” CENTER (0,0) FOOTSWITCH x: -0.775, y: -1.20 x: 0, y: -1.20 ø5/16” ø15/32” PHOBOS GERMANIUM FUZZ...
  • Page 9: Enclosure Layout

    ENCLOSURE LAYOUT Enclosure is shown without jacks. See next page for jack layout and wiring. 125B PHOBOS GERMANIUM FUZZ...
  • Page 10: Wiring Diagram

    GND +V +V JACK GND JACK GND GND PCB 125B Shown with optional 9V battery. If battery is omitted, both jacks can be mono rather than one being stereo. Leave the far-right lug of the DC jack unconnected. PHOBOS GERMANIUM FUZZ...
  • Page 11: Document Revisions

    Changed LEDR to 10k to work with a wider variety of LEDs. 1.0.1 (2022-10-18) Revised biasing instructions and changed both bias trimmers to 50k to allow for easier biasing of a wider variety of transistors. 1.0.0 (2020-07-03) Initial release. PHOBOS GERMANIUM FUZZ...

Table of Contents