Saturday, 16 January 2016

Faustone Fuzz Unit

   Faustone was kind enough to post their schematic on their website for DIY use, and they make great products. Support this cool company if you are able :)

Info from Faustone:

    "The Faustone Fuzz Unit is a replica of the rare Barnes and Mullins (B&M) Champion Fuzz Unit. The original pedals were built by Colorsound in London in the late 70s. Rebranded under many names —B&M, CMI, G.B., Pro’Traffic— electronically the circuit was the British cousin of the Electro Harmonix Big Muff, and —allegedly— it was featured on “A Girl Like You”, the Edwyn Collins hit single.
This Faustone version is based on my April 1977 original which was carefully dissected, studied and re-assembled. The circuit on mine is a tad different from the available Internet schematic, and features Zetex brand transistors instead of the ubiquitous BC184Cs.
The circuit is basically a clone of a Big Muff minus the fourth transistor position. In the Fuzz Unit, two ZTX383C transistors —with a gain of around 600— occupy the two first positions (Q1 and Q2). A lower gain transistor is used for Q3 —ZTX382B, gain of 150— which in my opinion is the key to achieving the characteristic musical flute-like sound of the original pedal."












This layout omits the 220K output resistor for increased output








Posted by at 01:34
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15 comments:

  1. zosotone16 January 2016 at 16:22

    Great! Faustone makes cool pedals. Maybe the most impressive it's the Valve Klipper (Laney Klipp channel).

    Thanks for the schematics Fausto.

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    Replies
    1. zosotone16 January 2016 at 16:27

      It would be nice to see a vero of this pedal.

      http://faustone.com/pdf/Faustone_Valve_Klipper_schematic.pdf

      Delete
  2. Travis16 January 2016 at 17:25

    Thanks zosotone! The Klipper was my introduction to Faustone, but I didn't realize that he posted the schematic for that one too.

    At any rate, I'm a bit uncomfortable uploading a layout for that on the main site. I have never drawn a layout with tubes or transformers and the lethal voltages found in that circuit are not something to play around with.

    With that said, I really want to build one, and it is a prime candidate for the amp section in the forum

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  3. Travis17 January 2016 at 15:31

    I'm building this to verify right now and I've noticed two mistakes. The top leg of the 470K at Q3 needs to come down one row so that it goes between Q3 base and collector. Also, I must have accidentally deleted the collector resistor for Q2 during editing.

    Sorry folks, if you hold off on building for an hour or two I should have this edited and verified shortly

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  4. Travis17 January 2016 at 20:17

    My build is working fine, but since I moved a few things around I'll keep this tagged as unverified for now just to be safe. Should be good to go though

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  5. Servant0718 January 2016 at 04:56

    Thanks for the post. Just built this and it is working, however the tone is reversed, so 1 and 3 need to be swapped and the output is really low. I looked at the schematic and it is noted that the 220k resistor at the output is optional, so I removed it and it is much louder now.

    I used MPSA18's (hfe around 660) for Q1 and Q2, and a 2N2222A (hfe 180) for Q3.

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  6. Travis18 January 2016 at 14:10

    Thanks servant07, I forgot to flip tone 1 and 3

    I'll update and tag the layout when I get back from work.

    Regarding the 220K output resistor, this cut too much output for me too. I dropped mine to 100K, but I may omit it altogether. I used BC550C for Q1 and Q2 and 2N2222A for Q3

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  7. Travis19 January 2016 at 04:06

    Layout updated and tagged. I also added a version without the output resistor so you can get some extra output.

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  8. BlueOysterCult21 January 2016 at 16:08

    Just build it today. Works but sustain is not famous.

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  9. Travis21 January 2016 at 19:19

    Hmm. Did you do the one with or without the output resistor?

    Maybe post some good pics of your build in the debugging section on the forum and I'll take a look. Sounds like there's a problem in your build. Mine definitely sounds really sweet with plenty of sustain

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  10. BlueOysterCult22 January 2016 at 13:22

    This comment has been removed by the author.

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  11. BlueOysterCult22 January 2016 at 16:27

    After changing the wrong resistor, it sounds awsome !
    Thanks all

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    1. Travis22 January 2016 at 19:51

      Glad you got it fixed! Hope you enjoy, I know I'm enjoying my build. This is a badass muff variant.

      One thing I've noticed about these muff variants with only one clipping stage is that they seem to mix in a bit of clean-ish signal into the overall output. My theory is that the 470K feedback resistor on q3 mixes in some clean signal, and since there isn't another clipping stage following that bit of clean signal makes it all the way through. It has a subtle but interesting effect on the overall sound

      Delete
  12. 0friendsrecordings29 January 2017 at 21:25

    I built this a couple of months back but the output was really low, even without that last 220k before the volume pot.
    If I bypass the tone stage (hook vol 3 between Q3 and tone circuitry) there is lots of hot fuzz at volume. I've tried checking for common errors on my build, though not sure I've tried the tone 1+3 swap. No joy though. That 33uF maybe wants to go negative straight to ground rail?

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  13. liquidify19 March 2019 at 03:18

    ever figure this out?

    ReplyDelete

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