Vintage Mu-Tron III

Discussion in 'The Stomp Box' started by Kozmo, Jul 2, 2019.

  1. Kozmo

    Kozmo TDPRI Member

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    I just acquired one of these in a package deal. Unfortunately it's not working properly.
    I know there are folks I can send it to for an overhaul but I thought I'd ask here first.

    So it "wahs" when engaged, like a wah pedal rocking back and forth, but it doesn't "auto-wah"- it doesn't react to individual notes or pick attack, no matter where I set it.

    Any Mu-Tron experts in the house?
    IMG_4493.jpg
     
    zippofan and BorderRadio like this.
  2. Utah Joe

    Utah Joe Tele-Meister

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    Try this: http://www.lsound.com/
     
  3. Kozmo

    Kozmo TDPRI Member

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    Thanks, Utah Joe.
    Yes, that's probably the best guy to send it to. But that'll cost me another $200. I'm not sure it's worth it.
     
  4. dan1952

    dan1952 Friend of Leo's

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    If you get it fixed it won't be original. Oh no!
     
  5. brokenbones

    brokenbones Tele-Meister

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    Have you opened it up and given it a visual inspection?
     
  6. Kozmo

    Kozmo TDPRI Member

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    Yes, looks clean inside- no burnt components. No loose wires.
     
  7. zippofan

    zippofan Tele-Afflicted

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    A schematic is available over on the Madbean site, I just completed a clone circuit and it sounds terrific. Look for the "Naughty Fish" build and forum threads. There is also one on General Guitar Gadgets but it's a variant.
    mutron_complete.jpg

    The Sweep circuit includes the Vactrols (LED/LDR) which in the original were custom made parts. The Madbean clone uses an Xvive part that mimics the original but isn't exact. Madbean's build doc would be a good place to start troubleshooting. I think you could find the original schematic on the web too.
     
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  8. Kozmo

    Kozmo TDPRI Member

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    Awesome. Thanks zippofan!
     
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  9. zippofan

    zippofan Tele-Afflicted

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    Good luck, I hope you are able to get it working again! It's an awesome effect, I really love it, from subtle to over the top it sounds great.
     
  10. sirbergersworth

    sirbergersworth Tele-Holic

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    I didn’t know this circuit was capable of an “auto wah” type of sound. I thought it was only an envelope filter. Have I been wrong all these years.
    I wonder if a cap is out of spec and the thing is self oscillating.


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