Wednesday, 5 December 2012

Marshall Guvnor

Very similar to the Drive Master posted a couple of days ago, but thought I'd include the full layout to keep things complete.  This version with a diode/LED switch as per a request I had.  If you'd prefer yours to be like the original and have fixed LEDs rather than this switch, then just solder in LEDs directly on the board as per the Drive Master layout.  The 10u cap will need to be moved 3 columns to the right.






19 comments:

  1. I was wondering about this pedal and am very pleased you put it up. I really like the Switch option. Much appreciated. Thanks. (Will Build)

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  2. Awesome, always loved that original Marshall pedal (one in the video). Isn't the Marshall Shredmaster the LED mod you have here. This is next on my list to build.

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    1. Finally built this, sounds wonderfully Marshall! I think I prefer the silicon diodes, but the LEDs (and lifted) also sound great. Thanks for this layout, gonna box this one :)

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  3. Ivlark, I built this pedal and it has great Marsahll tone and sustain but I bypassed your switch configuration and wired the diodes as per the original Schematic. The switch for me did not work and I believe it is wired differently to the original schematic, but being a novice I am quite willing to be proved wrong gracefully.

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    1. The original schematic for the Guvnor has LEDs shunted to ground. The switch allows you to choose whether you have LEDs or silicon diodes shunted to ground to give you a couple of different flavours of distortion (plus the diode lift option). I can't see how it deviates from any of the schematics I have. But thanks for verifying the layout and glad you're liking it.

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  4. Hi guys, I've one question. Regarding the red LEDs, what kind of red LED is it intended to use? 5mm or 3mm? low currant or standard?
    Is it the same?

    Thanks in advance

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  5. Any chance you could work out the Marshall Guv'nor's wayward son the Super Plextortion?

    http://www.diystompboxes.com/smfforum/index.php?topic=77421.msg635337#msg635337

    " . . . basically what you have is a non-inverting gain stage into an inverting gain stage into a baxandall stage into a jfet gain stage. You'll get close by using the marshall guv'nor's first two stages as the clipping. swap out the 680k in the inverting stage via a switch to a 220k/ 470k. baxandall after the led clipping diodes. go from there into a jfet gain stage (1k source). you'll have to dumb down the signal a bit before the jfet gain stage - use a trim pot for maximum effectiveness."

    I'm real interested in a good foundation Marshall in a Box to use with my Bassman LTD and have it down to the DLS mk III and the Plexitortion and want to build both to compare and choose a keeper.

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  6. Hi,
    Built this in a 1590BB as a dual build, along with a Drive Master. There are subtle differences between the two of these, I like using the Guv'nor with lower gain, and the Drive Master with higher gain settings.
    Here's a pic:
    http://imageshack.us/photo/my-images/832/3ush.jpg/
    I included the mods suggested here (it's in French, but the schematics speak for themselves):
    http://optimisetonampli.chez-alice.fr/exemple.htm#guv
    The idea is using an OPA2134 instead of the TL072, and (improving the) decoupling (of) the 4.5V and 9V, to improve the harmonic response. Works great! :)

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    1. Hi,
      I bought the GV1 when it appeared and later I've made the "optimisetonampli" mods too. It is really amazing !
      I recommend !!
      Mine is now True Bypassed as it sucked my tone (mainly on bend) when not engaged.
      Thank you for this so rich blog.
      Emmanuel

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  7. Built and boxed this one. Some great sounds to be had from it that's for sure. Thanks for the layout :)

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  8. I built this up and it sounds amazing. One question though... If I turn up the treble the signal becomes almost non-existent. There's a faint signal, but it's unusable. The pedal works great other than this one issue. It's something I can live with, but I'd love to be getting the most versatility out of this if possible. Does anyone know what might be wrong? Thanks!

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  9. Built one with Wampler Plextortion values, excellent!

    I used the values found here, but went with a JRC4580 and clipping switch: http://img404.imageshack.us/img404/8174/tonepadguvnorwamplerple.jpg

    The guy I made it for said it has kicked his Fulltone OCD off his pedal board.

    https://lh6.googleusercontent.com/-L65G4ylK3B0/VBPxnNJDdlI/AAAAAAAAAOY/JiSdbLlLiM0/w277-h510-no/IMG_20140911_122528_836.jpg

    https://lh5.googleusercontent.com/-xQgwqgxpILY/VBPxPBsj95I/AAAAAAAAAM4/EY3zINvkvaA/w287-h510-no/IMG_20140911_121531_560.jpg

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    1. Where did you find the Wampler Plextortion values? I've seen a couple of variations, which one's did you use?

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  10. Sorry but I could not listen to any soun difference using clipping diodes 1N4148 or the red leds.

    did you feel any sound difference ?

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    1. There should be a decent difference between silicon diodes and LEDs. Listen for a change in the character of the low/mid range. LEDs are generally more 'Marshally'.

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    2. I will try to listen to this low/mid range difference.

      Are there other kind of mods for this clipping stage ?

      Thank you very much.



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  11. I recommend to try infrared diodes. Voltage is lower than reds, so is autput volume, but tone/character is sweeter to my ears than default recommended red LEDs.

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  12. The originals had a built in effects loop. Where would I put it?

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    1. Here.
      http://optimisetonampli.chez-alice.fr/Download/Guvnor_modif.gif

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