This is a library of perfboard and single-sided PCB effect layouts for guitar and bass. I'm not an electrical engineer by any stretch of the imagination, just a DIY'er who likes drawing layouts. It is meant for the hobbyist (so commercial use of any of these layout is not allowed without permission) and as a way to give back to the online DIY community.

Thursday, July 9, 2015

Wampler Distortion Plus Mods

A while back Brian Wampler shared a bunch of mods to the classic MXR Distortion Plus circuit in Premiere Guitar magazine. It adds a tone control, a switchable soft clipping stage, a compression switch, and a bass boost switch.

13 comments:

  1. Wow brian mods...biggest thank for you brother :)
    Just 1 question, are this verified ?

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  2. The Drive pot is backwards but it works great. Mark it verified.

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  3. Built tonight, sounds really good with the mods! The gain pot is still backwards, so not sure if maybe the update didn't get uploaded. Still works as it should otherwise, thanks!

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  4. verified!
    I made some changes:
    Gain pot is better use log pot (as original wampler mods)
    Tone stack is useless, I changed for a100k pot and 22n capacitor and it works very much better (22n to 68n works fine)
    Thanks!

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    Replies
    1. And reversed tone pot for high tones clockwise

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    2. Buen día. Hoy 28 de julio lo acabo de terminar con la configuración de condensadores de Sergio. Esta excelente, suena de maravilla. Gracias a Efects Layouts

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  5. Hello,
    1 question, the image from Tranfer Image Library differs from what is above, is it ok to proceed with the one that is there ?

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    Replies
    1. How does the transfer image pdf differ?

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    2. Distortion pot is in reverse in either image library or here (log 1 to switch) :), but after closer look doesn`t affect the effect, only the pot would work opposite way.

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  6. This comment has been removed by the author.

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  7. This comment has been removed by the author.

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  8. Since C500k it´s a hard to find in some places I have been doing some simulation in lt spice and breadboard testing. The great Wampler Mods uses a A1M and 1k to increase the gain from 46dB (original) to 60dB (which is too much for my little 15w amp). The filter is made for the 1k and 220n, this way the 720 Hz is manteined (original high pass filter is made by 4.7k and 47n). So here you´ve got some values for using diferent potentiometers keeping the cut at 720 Hz:

    1meg = 60 dB
    500k = 54 db
    250k = 48 dB

    The 250k potentiometer is more likely to the original in lt spice frecuency renponse graph, much more with 1.5k and 150n instead 4.7k and 47n.

    For me.. ...A500K pot/1k Resistor/220n Cap, sounds the best in my amp.


    Saludos desde Venezuela

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