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Wednesday, March 23, 2016

Mad Professor Stone Grey Distortion

Here's the Stone Grey Distortion from Mad Professor. It's reminiscent of the Distortion +/OD250 circuit, but with a hex inverter stuck after the opamp. It also uses 2 JFETs in the feedback loop of the opamp for clipping. Original op amp is the TL051, but other single opamps can be used (Tl061, 71, etc). Should be an easy fit in a 1590B. Mind the jumper under the CB4069UBE.



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16 comments:

  1. UnknownMarch 26, 2016 at 7:44 PM

    Built this today with a TL071 and 2N3819 and it sounds great. I tired my Jazzmaster on it and my SG. I doubt I have to say it but this thing loves the burst buckers. The SG got some great crunch sounds and with drop D tuning it was instant Soundgarden sound. Outshined!

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    1. EndrjuJanuary 20, 2019 at 7:17 AM

      Hey. I have also build it, but have some issues with the signal. It is a little bit noisy and I think that the distortion knob is doing nothing... Any ideas?

      Delete
  2. BerkicauMarch 28, 2016 at 7:51 AM

    cody, have you tried using tl072?

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    1. Effects LayoutsMarch 28, 2016 at 9:17 AM

      The TL072 won't work in this as it's a dual op amp. This effect uses a single op amp. Other options would include TL061, NE5534, or LF351. A LM741 would also work in a pinch, but probably wouldn't sound as good.

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  3. fredJune 4, 2016 at 2:16 AM

    suhr riot pcb please brother!!!

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  4. DiegoHinoJuly 14, 2016 at 4:36 AM

    do you have a pdf file of this pedal? is it 1590b size? thanks

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    1. Effects LayoutsJuly 14, 2016 at 11:43 AM

      It's in the Transfer Image Library tab at the top of the page. Yes, it'll fit in a 1590B.

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  5. UnknownMarch 3, 2017 at 11:38 PM

    any substitute components for 2N3819??

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  6. Leonardo HalfeldSeptember 22, 2017 at 11:41 AM

    I was looking at the schematic to this one ( this http://3.bp.blogspot.com/-P2RCqMsl__A/TxLM0MEtCJI/AAAAAAAAAio/rVtTwB3v83g/s1600/Mad+Prof+stone+grey+schem.gif ), and i found an error in your layout. The 4.7uF capacitor should connect to the 10k resistor by the negative side and to the CD4069 by the positive side.

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  7. UnknownDecember 18, 2017 at 3:07 AM

    Awsome Awsome Distortion!!!
    Built it on Perf, sounds great
    Thank you very much

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  8. adminFebruary 14, 2018 at 6:58 AM

    This comment has been removed by the author.

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  9. dmitrogenDecember 31, 2019 at 8:48 AM

    Is there any other JFET that can be used in lieu of 2N3819?
    Thanks in advance, and Happy New Year!

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    1. Effects LayoutsJanuary 1, 2020 at 9:43 AM

      They're being used as clipping diodes, so you can use diodes or even a pair of MOSFETs like 2N7000 or BS170s

      Delete
  10. AlexAugust 19, 2020 at 2:15 PM

    Built this yesterday with 2N7000 and TL061 and it sounds wicked.

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  11. Zaraki1337April 9, 2021 at 11:16 AM

    Anyother pots that can be used intead of A1M ???

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