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, June 15, 2015

Xotic EP Booster

Here's another circuit from Xotic. Simple JFET boost with an output buffer borrowed from the Tube Screamer. Originals have 2SP1815 transistors with BCE pinout, but I've laid this out for the more common 2N5088 with CBE pinout. The originals also have the Bright and Fat switches internally as DIP switches. Having these externally should be much easier on the user, and it shouldn't be too hard to fit in a 1590A. Well, no harder than any other 1590A layout. 


48 comments:

  1. Verified!sounds great!Thanks!

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  3. HI, What's the correct dimension do print this board? Thanks

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    Replies
    1. Check out the Transfer Image Library tab at the top of the page.

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  4. could you please tell me the offboard layout ? what is the meaning of both SPST,
    is it using foot pedal or not ?

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    1. They're individual toggle switches. One controls the brightness and the other the fatness. In the original they were internal switches on the circuit board (DIP switches as I mentioned above), but to get to them you have to open the pedal up. Making them external makes it more versatile in my opinion. The footswitch you would wire up the way you normally would, and there are a multitude of diagrams for that online.

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    2. o i see it is a toogle switch, this spst looks like have 3 pin on it.
      you write in this, there is two toggle.

      one is fat, another one is bright.
      however you only mention the pin 1 and 2 going where.

      my question is where is the pin 3 go ? for the fat and bright toogle switch ?

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    3. SPST switches only have 2 pins. You can use something like an SPDT or DPDT if that's what you have on hand, just use the first 2 pins and ignore the rest.

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    4. so in this design, it will be 3 spst ?

      1. bright
      2. fat
      3. boost.

      is it correct ?

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    5. ooooh my bad.. the boost is the potentio meter for reverse log 10 k.
      sorry man. thanks for your attention.

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  5. The 2/3 pot conection, its for conect the two together or one of them?

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    Replies
    1. Lugs 2 and 3 should be connected, then connect a wire from there to the board.

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  6. Have some minimum voltage for the capacitors?

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    1. Personally I use 35v or 50v for electrolytics and I think my film caps are rated at least at 100v. No idea what the originals use, but that shouldn't effect the tone at all. Just so long as they're higher than 18v

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  7. sounds great!!!!!!!!!!! wow.........

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  8. Hey there,
    I've already assembled and finished.
    It works well !!!!
    but...
    Fat switch absoultamente not appreciate any change.
    any ideas??

    P.S. IF switch the brigth makes its function.

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  9. Really!! Fat switch not appreciate any change.
    any ideas??

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    Replies
    1. I'm with the same problem... maybe it isn't too noticiable as we expect.

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  10. Weird that it's not having any affect. You could try experimenting with the values of the fat switch caps. They're the bottom most 10µ and 100µ caps on the layout.

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  11. Hey there,
    I changed 10uf for 1 uf, and nothing.
    and I changed 100uf by 220uf and neither nothing

    thanks for reply

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    Replies
    1. Wow. You'd think there'd be a change. I wonder if you switch has a short or something...

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    2. I'm with the same problem :/

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    3. Same problem here!! Fat switch doesn't do anything =\

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  12. tested, it works fine. Thank you

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  13. Hi, Congrats for your amazing blog! very inspiring! I was wondering if you can share the schematic here ?

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    1. Did you try googling it?

      https://www.google.com/search?q=ep+booster+schematic&espv=2&biw=1266&bih=818&tbm=isch&imgil=R-y9qgn_lplkIM%253A%253BUzfoqEpoI4DTdM%253Bhttp%25253A%25252F%25252Frevolutiondeux.blogspot.com%25252F2012%25252F01%25252Fxotic-ep-booster.html&source=iu&pf=m&fir=R-y9qgn_lplkIM%253A%252CUzfoqEpoI4DTdM%252C_&usg=__4Gkp0hHlIM0xq_qdDlkXpSva38Y%3D&ved=0ahUKEwjWiZKYuYTNAhVIOiYKHWVmAUkQyjcIKQ&ei=RpVNV9bOJMj0mAHlzIXIBA#imgrc=_

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  14. I do not potenciomentro C10K
    I can put another in his place?

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  15. just build this one.nice little boost.the pot works in reversed.i believe it should be 1&2 to ground
    http://revolutiondeux.blogspot.gr/2012/01/xotic-ep-booster.html

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  16. I'm with the same problem: I didn't ear any change in both switches.
    I tried another caps, check continuity, and nothing.

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  17. BTW: I tried with F245A fet, and the results are the same as 2N5457.

    What does the last section in this circuit? I mean the 2N5088/etc. transistor.

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    Replies
    1. That's an output buffer. Pretty much the same simple transistor buffer that's used in a TS808.

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    2. What I supposed ...
      Thank you!

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  18. I'm having a problem with the circuit. I build two, and both work in the buffer part and the switches bu the pot does nothing when I turn it.any idea what is going wrong?

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    1. I have the same problem, I thing that burn the fet with the solder iron, maybe the next try, I have to use sockets. Could you measure the voltages in the transistors??

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  19. i am confused in caps the one shade part with (-) is the negative part? thanks for answering guys.

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  20. I've done, and works well, but the pot doesn't do anything, and I have less than unity gain. Could someone post the correct voltages when the pedal is totally ok?? Just for reference, I believe that I have a wrong fet or maybe burn it when soldered. Thanks!!

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    1. It works!! Maybe a faulty pot, because today I replace the pot and voila!! But the fat switch still do anything. =[

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  21. Sir can i have a complete details about the parts.. Noob here ��

    For example the resistor watts, IC name and the code like that sir...

    Jake from Philippines

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    Replies
    1. Resistors are always 1/4 watt unless otherwise stated. The IC (or transistors in this case) are listed in the layout.

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  22. Works great! But I´m experiencing some very annoying humming. Any ideas??

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    1. Well... turned out it was (of course) the power supply. Now I just can´t hear any difference from the Fat Switch...

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  23. This comment has been removed by the author.

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  24. mind dont have any output sound. i am using 2n2222 instead of 2n5088 and 2n5458 instead of 2n5457? is it wrong? pls help

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