Seems a lot of people are asking for a layout of this effect.

Update (27.10.2011): Now verified thanks to Glenn. That was fast!

Update (09.10.2012): I was asked to refrain from using the company and product names, so layout has been updated accordingly.

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48 thoughts on “Request: W****** Dlexi-Prive

  1. Hi Kramer,
    I haven’t built this circuit myself, so I can’t really tell you. Have you tried using another brand of JFETs?

  2. Hi all!

    I built this pedal three times already, sounds great, but never seems the original pedal. I set all of drain voltages to 4,8V, that’s OK. It sounds like the original pedal but with much less gain.. If i set gain pot to 12’o clock, the sound is still clean, not crunch as we hear at the original..
    Does your pedal works so? or have you any idea how can i increase the gain?

  3. Sorry to hear that, Dario. I’m afraid there’s little more I can do to help. The only thing I can think of is that you’ve got one of the component values wrong. Have you double checked that R11/R12 are 15k? C8 is 2n2 and not 22n? C9 is 10n and not 100n? And C7 is 1u and not 1n?

  4. Hi Harald!

    I checked all off the things that you recomended but still no effect out of the tone pot. I even resolder everything onto the new veroboard.
    Best regards

  5. Hi Dario,
    So, if I understand you correctly it seems like the tone control is stuck at one extreme and turning it does not do anything? I’m assuming you’ve done the three additional connections (lower right-hand side of layout; tone #2,#3 and volume #1 to ground, and volume #2 as your output).
    – Make sure you’ve got C9 positioned correctly on the board (“C16” to “E16”), you’ve got a proper trace cut next to C9 (at “E14”) and that the “E” track where you have C9 connected does -not- accidentally connect to the “F” track (use your DMM continuity test).
    – Make sure you’ve got a working tone potentiometer; rotate it fully CCW and lug #1 should read short to lug #2 and approx. 25k to lug #3, now rotate fully CW and lug #1 should read approx. 25k to both lug #2 and lug #3.
    – Make sure that tone lug #1 connects to the “E” strip as indicated on the board, and that tone lug #2 connects to ground (lug #3 isn’t strictly necessary and can be left disconnected).
    That’s what I can think of off the top of my head. Hope you’re able to solve it.

  6. Hi Raul, the gain pot works by letting a smaller or larger portion of your signal through to the rest of the circuit, which may also affect the output volume which is normal. But because of R4 (1k) you should always have -some- signal passing by the gain pot. You could check that lug #1 on the gain pot is not shorted to ground, but reads approx. 1k. You should also make sure you have properly biased JFETs; try a whole bunch until you find ones that each read about +4.5-5V drain voltage.

  7. Hi Harald!
    Got really glad when I found your site on a net. I built the DlexiPrive as test but now that it’s finished I can’t seem to get the tone control working. The pedal sounds like all the treble is rolled off. what to do. I can’t use it as it is.
    Best regards
    Dario (Sweden)

  8. I did this one and it worked, but the gain pot is also working as a volume knob, when I turn it counter-clockwise dicreases the gain and the volume too, even mutes. Do you have any ideia of what might be happening?

  9. Hi Kramer, my immediate hunch is that volume lug #1 isn’t making proper contact with ground. Can you double check for cold solder joints, broken wire etc.?

  10. Hello Harald, I bought the parts to build this one but couldn´t find the 25K audio pot, so I bought a 20K and a 50K (both audio). Wich one do you think is better for replacement

  11. Hi!

    I built this pedal, sounds great, but very loud..
    I tried to change volume pot for 500K and 1M, but the volume did not change.
    If i increase the input resistance, the sound will be badder.
    Have you any idea, how can i to make the volume lower and changeable?

  12. Hi Raul. You’re right about R2, R5 and R9. Most JFET amp emulator builds call for 100k trim pots, but 50k is probably more than enough. As long as you’re able to adjust it so that the drain pin on each JFET sits at about +4.5-5v you should be fine.
    Good luck and happy DIYing 🙂

  13. Hello Harald, I would like to build this layout with trimpots instead of resistors on the drain oh the J201s. Just to check, I should replace R2, R5 and R9 insn´t it? Do you think that 50K is a good value for the trimpots?
    Please correct with I´m wrong, I´m kinda new in this DIY stuff.
    Greetings from Brazil! 🙂

  14. Hi!

    Somebody would be able to send a sound sample to me?

    my email address: tamas.gyori1988(at)gmail(dot)com

    Thank you!

  15. Erik. Your issue is most likely due to JFETs having a large variance, and one or more of yours are mis-biased. Typically you’d see JFETs used with trim pots connected to drain (e.g. most of the preamp emulator layouts here) which allows one to use any JFET and adjust the drain resistor to suit it. The other way of looking at it is what you see in Wampler’s effects; there’s a fixed drain resistor and you need to select the right JFETs for the job. Ideally you should have a good number of JFETs at hand, go systematically through the circuit one stage at a time and find transistors that measures approx. +4.5V – +5V at drain.

  16. Hi Harold,

    I built this effect but I got some problem. I got sound when I hit my guitar strings hard, but it sounds like it’s going trough a gate first, a bit like the gate effect on the Z.Vex fuzz factory. It sounds very harsh. Any thoughts on this?


  17. They’re both N-channel with the same pinout, but I’m concerned the J201 is a general purpose amplifier while the J111 is mainly meant for switching applications. It might work, but I would try to find some 2N5457’s instead.

  18. Hi Harold. I can`t seem to find the J201 in Brazil, but the guy at the Elec Store told me to use the J111 instead. Do you know if that`d work ok?

    Thanks in advance and great job!

  19. Grab a bunch of them put them in the circuit and apply power. Now measure the voltage on the drain pin of each; you want something like +5v. If any of them are off, turn off power and swap in a new one, then turn power back on and measure again. Rinse repeat until you’ve found good FETs for each stage.

  20. Hi, How do you match JFETs? I keep on hearing this-that you need to match JFETs …But how is it done? Can someone throw some light?

  21. Hi, I built this using IvIarks layout. Everything works fine except my tone pot has no effect? like it’s completely bypassed.

    Any ideas or anyone else experienced this?

  22. Just finished and it’s just GREAT!!! 😀 Great tone, great sound… the Bass switch adds so much to the sound! Thanks Harald!:D Now let’s wait for the pinnacle 😀 😀 😀

  23. I believe the original use J201s. Be sure to source a lot of them so you can hand pick the ones that give you the correct drain voltage.

  24. sorry, I should have been more specific, is it n-type or p-type transistors?

  25. Hi Harald

    I was wondering if you have any recommendations for transistors for this build

  26. Not sure to be honest, but should be easy enough to find out. Breadboard the stage and try different values. I do believe you’ll need different source resistors for different transistors, though.

  27. Harald

    I was thinking about the gain on this pedal. Its a little anemic. I like the sound of the pedal but I would like to wring a little more gain out of it. I noticed on some other pedals with similar topology, the source resistor of the tranny ( I guess what would be analogous to the cathode resistor on a tube )is a lower value – 1k for the plexidrive, 680 or 330 R for the others. I know on a tube that lowering that cathode resistor will up the gain. Do you think lowering that source resistor would have the same effect of more gain here?

    Just curious…

  28. There’s an illustration on the “Schematics & drawings” page. With the shaft pointing upwards and the lugs towards you; 1, 2, 3 from left to right.

  29. Thanks for the layout guys. What are the pin outs of the Pots? Looking at back of pot is it 1,2,3? or 3,2,1? Thanks

  30. I just built this today, it turned out really well. One question regarding the bass switch, there is quite a big difference in terms of volume between on and off. I don’t have access to the original pedal so I don’t know if that is expected behaviour.

    Anyone else having the same result?

    Thank you so much for creating the layouts, it really saves us a lot of time!

    Now it is time to turn my DRRI into a Marshall and play some ZZ Top!

  31. Hi Glenn,
    Im am very interested in Pinnacle pedal (and also in the Plextortion pedal, if you know). I wish build it but I don’t neither the schematic nor the vero layout. Can you tell me where I can find them (or kindly send me a mail attachemet with vero layout and/or schematic)? Thank You. Ismo

  32. Hi, Gary. If you click on the layout image a couple of times you’ll eventually get to the real-sized one. It’s something about how this WordPress software treat images…

  33. Hi!

    I think that this pedal sounds great, I’d like to try building one.
    The layout diagram on this page is too small resolution to read or print,
    do you have a readable schematic or layout that you can post or send?

    Many thanks

  34. I built this over the weekend, sounds great! Just like the YouTube videos. Thanks for another great layout…

  35. Dr.Robb, to my ears the pedal doesn’t need to be tuned, it works fine without a trimmer.

  36. FYI – The only reservation I see between this and the actual Wampler inside pedal shot is….there are no trimmers in this Vero layout to adjust the bias to the JFETs!!!

    Dr Robb

  37. Hi Harold I built this after work and it sounds very nice. Sounds just like the videos.
    Thanks again bro, now i have 4 wampler built pedals. I build a pinnacle on perf board, thats a nasty animal. I am going to get a paypal account, to help pay for all you kindness. Remember me, I still want the blues driver, but no hurry….cheers Glenn

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