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Wednesday, May 13, 2015

Ross Distortion

The Ross Distortion is very similar to two other famous distortion boxes of the late 70s (MXR Distortion +, DOD 250). However, it uses one side of a 4558 dual opamp instead of the single opamp (741) found in the the other two, and a few other tweaks in component values. There are two versions of this circuit: the Tan version, which uses 2 germanium diodes for clipping (originals used 1N270s, but 1N60Ps or 1N34As should also work just fine), and the Black version, which uses 3 silicon diodes for asymmetrical clipping. I've drawn up 2 layouts for each version, both will fit in a 1590A. The only difference is improved power filtering and added polarity protection in the larger layouts. The yellow 1µ caps are tantalum.





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16 comments:

  1. UnknownMay 15, 2015 at 11:21 PM

    This comment has been removed by the author.

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  2. dtgehringMay 17, 2015 at 3:09 PM

    Thanks for catching that. Fixed.

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  3. pete_gJanuary 15, 2017 at 2:37 AM

    Seeing the early tan version is exactly like an MXR Dist + can you use a 741 chip in it instead?

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    1. Effects LayoutsJanuary 15, 2017 at 8:16 PM

      In theory yes, but not with this layout as the 4558 is a dual opamp and the 741 is a single. So the pinout is very different. If you want to use the 741 chip, check out the Drivestortion project.

      Delete
    2. pete_gJanuary 15, 2017 at 11:47 PM

      Would there be much noticeable difference in the sound with the 4558 and 1n914 diodes goat the MXR Dist + uses?

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    3. Effects LayoutsJanuary 17, 2017 at 9:34 AM

      Not a ton. Just a different "flavor" if you will. That's the great thing about this circuit. There's lots of tweaks you can make to it to fit what you want.

      Delete
  4. pete_gJanuary 15, 2017 at 11:49 PM

    Damn autocorrect! That.
    Not goats. Not kidding!

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  5. romdosJune 12, 2018 at 4:45 PM

    This comment has been removed by the author.

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  6. romdosJune 13, 2018 at 3:06 PM

    Is there a way to make Gerber files (or does anyone have one?) from those PDFs of the Ross Distortion layout? I want to have them made with an online PCB company.

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  7. MetalheadJuly 29, 2018 at 8:48 AM

    Can i use 4148 diode?

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  8. MetalheadAugust 9, 2018 at 10:21 AM

    Verified, i did the black version 1,

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  9. João LimaDecember 16, 2021 at 3:30 PM

    Hoje, no horário de almoço montei um, versão TAN... E estou me divertindo bastante! É um bocado brilhante de mais, sobretudo com singles, mas rugiu lindamente no meu "Alien Rocket". Circuito bastante simples, deve rolar umas mods pra reduzir os agudos, reforçar os graves e quem sabe um pequeno aumento de drive...

    Saudações do Brasil.

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    1. Effects LayoutsDecember 18, 2021 at 10:38 AM

      Try increasing the value of the 10nF input cap to 22-47nF. Also you can adjust the value of the 1nF cap that comes off Volume 3 to ground as that's bleeding off treble. Try 2.2-4.7nF.

      Delete
    2. João LimaDecember 29, 2021 at 8:10 AM

      Obrigado pelas dicas. Vou fazer os ajustes pra ver como vai soar.

      Delete