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.

Monday, August 21, 2017

JHS Charlie Brown V3

Unrelated to the Angry Charlie circuit, the Charlie Brown emulates the brown sound of a JTM45 amp and is a variation on the zVex Box of Rock without the boost section. The input stage is an AMZ Mosfet Booster (replacing the SHO input stage of the Box of Rock to avoid crackle in the gain pot), and the tone control has been modified to include the AMZ presence control.


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29 comments:

  1. ArcadeAugust 22, 2017 at 10:17 AM

    Nice pedal !! i will build it very soon.. I'd always thought BSIAB was an Charlie Brown, do you have the link to the schematic?

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  2. UnknownAugust 23, 2017 at 9:03 AM

    Just finished this morning but unfortunately there is no signal passing through. Checked for solder bridges but found none. Will check again once I get home from work.

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    1. UnknownAugust 23, 2017 at 9:07 AM

      Is there a way to upload photos in the comments?

      Delete
    2. Effects LayoutsAugust 23, 2017 at 9:30 AM

      You can post links to photos hosted elsewhere, but you can't embed them.

      Delete
    3. UnknownAugust 23, 2017 at 3:19 PM

      Ok cool... I got it working but it really gated. Tone control works and it get even more gated when I turn up the gain pot. When it's all the way down the signal gets through easier. Is the 9.1v zener diode clipping the signal too much? Or mis biased fets? Think I'm going to try 2n5457s and j201s and see what happens. If anybody has any ideas let me know thanks. I can give voltage reading if need be.

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    4. Effects LayoutsAugust 23, 2017 at 4:11 PM

      The zener is there to protect Q1. It's not clipping anything. I would try adjusting the values of the resistors going to the drains from the voltage rail. I wouldn't try subbing the MOSFETs for JFETs. You could sub 2N7000s for the BS170s. Just rotate them 180º.

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    5. UnknownAugust 24, 2017 at 6:16 AM

      Ok thanks😀. I'll put some sockets in for those resistors and give it a go. I also noticed on the gut shot that's floating around on fsb that there are three 22n box caps on the board. Wish I could see the trace side... I'll let you guys know what I figure out in a few.

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    6. UnknownAugust 24, 2017 at 7:18 AM

      You can mark it!! Got it working!! Had a cold joint on one of the drains of the bs170. Sounds good too!! Thanks for the layout man!!!

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    7. Effects LayoutsAugust 24, 2017 at 11:35 AM

      Cool! Glad you got it working.

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    8. UnknownAugust 24, 2017 at 3:06 PM

      Only thing is the presence pot... Think it has anything to do with the 22n in the gut shot pic?

      Delete
    9. ArcadeAugust 24, 2017 at 5:17 PM

      Check this mods for the BSIAB circuit, it uses the same tone control, i think #2 is the one on this pedal... http://postimg.org/image/qz49x137n/

      Delete
    10. Boba7August 24, 2017 at 5:29 PM

      The schematic of the pedal hasnt really been verified, it's based solely on gut shots (see the FSB thread).
      The presence pot is a mystery to me, I think we must have missed something, or the pot must be a much higher value, cause as is, it cannot make a difference.
      Of course you can try various tonestack values, and find the ones you prefer. But we dont know for sure what values the Charlie Brown uses.

      One thing seems sure to me: the 100n going to Tone3 should be 10n.

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    11. Boba7August 24, 2017 at 5:35 PM

      Also... the 1nf (input cap) should be 100nf, and the 100nf on the left going to 470k/470pf should be 22nf.

      Again, careful, the schematic posted on FSB isnt accurate.

      Delete
  3. sergioAugust 23, 2017 at 11:26 AM

    This comment has been removed by the author.

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  4. Boba7August 23, 2017 at 5:10 PM

    The schematics have not been verified. I posted myself a few message on FSB, based on what I could guess from the gutshots. But the contour pot value isn't verified.

    And I feel pretty sure the 100n going to tone 3 should be 10n.

    The contour pot always seemed odd to me.

    Anyways, I don't think you should totally trust the schematics posted on FSB.

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    Replies
    1. Boba7August 24, 2017 at 5:36 PM

      Also... the 1nf (input cap) should be 100nf, and the 100nf on the left going to 470k/470pf should be 22nf.

      Again, careful, the schematic posted on FSB isnt accurate.

      Delete
    2. UnknownMay 28, 2018 at 4:22 PM

      Just thought I'd share in case it is helpful to someone - I was able to get a useful Presence control by replacing the 82k resistor with something between 3-8k. Not sure what the CB actually has in there, but I'm using a 5k6 currently and it works well. Figured this out after comparing the tone circuit in the layout to the AMZ Presence Control (http://www.muzique.com/images/tone2c.gif).

      Delete
  5. UnknownJanuary 4, 2018 at 7:46 AM

    And what about Gain pot? Do anything, but after 3/4 made evil gain. Maybe must be C characteristic?

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    1. UnknownJune 10, 2020 at 10:46 PM

      Same thing here. Have you ever figure that out?
      I'm thinking of trying a C5k pot, but I do not have it handy at the moment.

      Delete
  6. UnknownJuly 20, 2018 at 7:28 PM

    Good Nigh, one question This project is working well?...I built It, but didn't work, Maybelline i did something wrong here, i'll be wait for coments...thanks

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    1. UnknownAugust 13, 2018 at 2:17 PM

      Yes, it´s working fine. Just built two this weekend. The first worked in the first attempt, but I had problems with the second. Nothing serious, mauybe a bad weld. Really cool distortion, much better than my Boss DS2.

      Delete
  7. andyJanuary 7, 2019 at 1:28 AM

    can i replace 10M Ohm resistor with 20M ?

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    Replies
    1. Effects LayoutsJanuary 7, 2019 at 9:07 AM

      Use two 20M resistors in parallel and you'll have 10M of resistance.

      Delete
  8. Matheus TostaJanuary 24, 2020 at 11:17 AM

    Is it really verified? I checked at least 5 times and it still not working :(

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  9. giuspolidoroApril 26, 2020 at 12:40 PM

    I built this one and it works, except the presence control.
    Someone had the same problem?
    I'll try to change components mentioned on comments above.

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    Replies
    1. AlejandroFebruary 18, 2021 at 7:57 PM

      Did you have success changing components to make the presence control work?

      Delete
  10. AlejandroFebruary 14, 2021 at 1:44 PM

    Hello!! Nice job on this one!!

    I am just facing an issue with presence control.. it doesn't seem to chance anything.

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  11. giuspolidoroNovember 13, 2021 at 6:36 PM

    Dear all, the presence control will not work as Charlie Brown v.03 on this way...
    Please, look at the FSB discussion https://www.freestompboxes.org/viewtopic.php?t=14501&start=40

    ReplyDelete

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