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Friday, November 14, 2014

Monolith Oracle Fuzz

This is a pretty cool fuzz box. It's a cross (sonically anyway) between an early Vox Tone Bender and a Big Muff. It uses PNP germanium transistors, but still uses a negative ground power supply. Originals have OC76 transistors with hfe of around 100 for Q1 and 300 for Q2. 300 is high for most PNP germ. devices and might be hard to source, but I've read of people using trannies with typical Fuzz Face gains (70, 100) with good results. The switch on the original is a push/pull on the 250k pot, but a DPDT switch can also be used.



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8 comments:

  1. melassebandMarch 18, 2019 at 9:04 AM

    works well. Heavy great sounding fuzz between bender/blackrumuff territoty, with a GT115V - 167 hfe as Q1 and GT115D - 323 Hfe as a Q2. Color2 to Output3, Output2 to fx output. thnx u storyboardist!

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    Replies
    1. Effects LayoutsMarch 18, 2019 at 9:15 AM

      Thanks for verifying!

      Delete
    2. AlexFebruary 2, 2023 at 2:31 PM

      Hello! I created it the other day. I used GT403 hfe 100/300, replaced the potentiometer B1M with A1M, but I lack a little gain and sustain (perhaps this is a feature of transistors), I plan to try to add a booster via a DPDT switch in the future, I tried MICRO BOOSTER, it is too loud, maybe a VOX booster will do . As it is relevant for someone, IN should be through DENSITY 2, then the DENSITY potentiometer works normally (in my opinion). Thanks for the layout!

      Delete
  2. LukeJune 24, 2019 at 10:25 AM

    I think the transistors are backwards/upside on this. The emitter is supposed to hook up to the 820/100k resistors according to the schematic: https://s76.photobucket.com/user/IvIark_2006/media/Layouts/Schematics/Monolith-Oracle-Schematic.gif.html

    Of course, I might be totally wrong--it wouldn't be the first time.

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    Replies
    1. mrJelleBeatJune 28, 2019 at 7:29 AM

      Hmm, I was thinking so as well, will try it right away

      Delete
    2. mrJelleBeatJune 28, 2019 at 7:21 PM

      I've tried the schematic you've provided and that one works perfectly (this pedal is a beast!)
      But turning the transistors around seems to work as well o.0
      This could be due an improvisation I had to do, for I had no 1M pot laying around.
      Since this effect is ground negative, I would stick to the schematic you've found.
      Hope it'll help you out.

      Delete
    3. LukeApril 19, 2020 at 6:05 PM

      I had success flipping the transistors around based on that schematic. After not having success with the layout above (the rest of the layout is great!)

      (I just realized that I was the original commenter on this--I must have given up for a number of months, then having gone back to it during quarantine, had success.)

      Delete
  3. BloozestringerAugust 15, 2021 at 1:29 PM

    What’s the bias voltage on Q1 and Q2?

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