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.

Friday, August 19, 2016

Wampler Velvet Fuzz

The Velvet Fuzz is a unique fuzz that combines amp emulation and 2 different selectable fuzz tones. The toggle selects between a LM386 (Tight) circuit, and a 2N5089 (Big) circuit. These then push a Plexi Drive circuit that gives the Marshall amp emulation. The modular nature of this design gives you the option to have not only a Velvet Fuzz, but a Plexi Drive in the same box. The board is laid out for board mounted pots and I've included trimmers to help bias the J201 JFETs. I've also included a switch diagram to show how to wire the toggle switches.



59 comments:

  1. where i can get schematic,? Please

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  2. I intend to take out of this pedal, but, for me, toggle switches wiring is little confusing. We have two switches, right? One is DPDT for changing from "big" to "tight", and another is 3PDT footswith? Well, where to connect "OUT" from volume 2 on 3PDT switch? Where is classic "IN" from PCB? Also, where to connect LED, input & output 6.3mm jack, and what it means: "fuzz in & fuzz out? Where they are on PCB? Also, there is "input" wire on DPDT? Where to find that "input" item on PCB? Apologies to my beginner questions. :)

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    1. Use this kind of toggle switch
      http://tinkersphere.com/buttons-switches/1112-9-pin-toggle-switch-3pdt.html

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    2. Both the switches in the diagram are toggles, not footswitches. The DPDT allows you to bypass the fuzz stages to just have a Plexi-Drive. This is a mod and not in the original. The 3PDT is what selects between big and tight. If you don't want the optional DPDT, the input wire from the footswitch would go to Fuzz In on the 3PDT pictured above, and the Fuzz Out on the 3PDT would go to the Plexi In pad on the board. The rest of your questions can be answered either over on the General Layout Notes tab or with a google search for footswitch wiring. Also if you're new to building effects, you might want to tackle something a little simpler before taking this one on.

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  3. I understand now, thank you very much! I will start to make this pedal as soon as I get all the parts! :)

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  4. Possible to set up the Plexi and fuzz on separate 3PDTs?

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    1. Totally. Use a 3PDT gootswitch instead of a DPDT toggle and use the 3rd row for LED indication

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  5. This baby is VERIFIED! ;)

    The only problem that i had were bad J201, after replacement with new ones, fuzz is vorking like a charm!!! I do not have jet toggle 3PDT switch, because that i connect wires directly. ;) As soon as i get 3PDT toggle switch and led diode holder, i will finish enclosure. ;)
    Pictures:
    http://www.upslike.net/imgdb/plocica-98768c.jpg
    http://www.upslike.net/imgdb/unutrasnjost-e645d4.jpg
    http://www.upslike.net/imgdb/kutija-30d46c.jpg

    P.S. in many schematic, pin 5 of LM has 220n cap, not 1u, so i replace 1u cap with 220n cap... is that o.k.?

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  6. Btw. thank you very much for free PCB images!!!

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  7. Also verified for me (perfboard layout) with the optional dpdt you added. It works very nice, thanks again for this great layout. Also thank you for the dpdt, it's a great idea.

    http://dl.dropboxusercontent.com/u/9520625/20160904_133838.jpg

    http://dl.dropboxusercontent.com/u/9520625/20160904_133641.jpg

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  8. Great job guys! Those builds look fantastic. And Rade, you're right. That 1µ cap should be 220n. Thanks for catching that. I'll update the layout.

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  9. Final look of my build: http://www.upslike.net/imgdb/Wampler_Velvet_Fuzz-30dcdc.jpg
    BTW. great fuzz pedal!!! :)

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  10. Where can we get the schematic from? I don't know what FSB means. Thanks

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    Replies
    1. Freestompboxes.org It's a forum with a pretty good search function.

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  11. I want to connect two 3PDT on this pedal, to change from plexy for big, how would this connection because it still has the exit and the entrance of the tigth?
    Could you help me with this wire connection please great man, tanks

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    Replies
    1. Not really sure what you're asking... Are you wanting to make the Plexi/Velvet switch a foot switch with LED indication? If so, wire it just like the diagram above and use the 3rd column of the 3PDT for the LED.

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  12. Okay, I want to put foot switch 3PDT, to step, to select the two modes: and the other to activate the pedal, the doubt and which wire to use for input of this switch?

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  13. Great fuzz, thanks!

    http://i.imgur.com/4FvhCGf.jpg
    http://i.imgur.com/jpTicL4.jpg

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  14. Does the gain and tone knobs works when in "plexi" mode?
    Thanks

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  15. Hi.first of all, thank you for answering my previous questions, on this and other layouts.
    I made my first pcb with this layout and now that I look at it, I believe with putted double holes for some componentes, like the 100nf cap next to the trimmer on the left. Is this so we can fit caps of different sizes?

    Also, what values (and where) should I get when adjusting the trimmers?

    Thanks again

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    Replies
    1. Yes, the double holes are different size caps. Set the trimmers to around 4.5v (measure at the drain of the JFETs).

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  16. Hello,

    When i have the switch in Tight mode, i have sound, but in big mode, i don't.
    The crazy thing is that i don't event have audio when probing at the input jack tip (in big mode)!

    WTF? How is this possible? I thought that i wouldn't have audio in the input jack in case it was grounded...


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  17. I had an unwanted solder bridge that was causing the problem,it's fixed now.

    The pedal sound really great, thanks a lot for all these great layouts.

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  18. Super impressed with this pedal. I have a love/hate relationship with most fuzzes but I can't get a bad sound out of this one. Thanks for the layout!

    I worked up a channel switch 3PDT scheme from your offboard wiring for the Grey Channel. Using a blue/green bi-color LED. Opted to leave out the switch to bypass the fuzz section as I have a plexi drive already.

    http://imgur.com/a/lub6m

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  19. Hi, a little late to this party, but really interested in building a switchable plexi / fuzz in a box. Do the pots control the plexi gain / volume as well, or is that using the trimmers?

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    1. Actually looking at the schematics on FSB, I see the "fuzz" control controls gain in the plexi circuit as well.

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    2. The trimmers are there to bias the JFETs in the Plexi portion of the circuit. The fuzz is fixed, though the Fat/Tight switch selects between 2 separate fuzz circuits.

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    3. Thanks for the reply, I see that now. I have a question from anybody experienced with the Velvet Fuzz, is there any reason why I couldn't mod an actual Velvet fuzz to bypass the fuzz circuit and go straight into the plexi circuit. Seems like it wouldn't be too hard, and all the connection points exist on the fat/tight switch don't they?

      Also wondering if bypassing the fuzz section causes a decrease in volume?

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    4. Also looking at the normal plexi drive schematic against the velvet fuzz, when bypassing this fuzz it goes through a 1K resistor in series, should this be skipped too and go straight into the 100n capacitor?

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    5. I've tired to do the switching with a single 4PDT on/on/on, let me know if anything looks not right: http://jameslow.com/2017/11/24/wampler-velvet-fuzz-4pdt-plexi-switch/

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  20. Hey all! Just wondering where the "Input" to the footswitch comes from on this circuit. I don't see it labeled on the board, so I was just wondering if someone could point me in the right direction. Thanks!

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  21. Hello, first of all congratulate him on his great work.
    I have the doubt if 3dpdt must be ON OFF ON or it must be ON ON.
    Thanks in advance and greetings

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  22. This comment has been removed by the author.

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  24. Hi, verified and with brutal sound, excellent work as always friend!
    The only thing that has surprised me is that when I lower the fuzz pot to zero it cuts the volume, that is, it controls the amount of fuzz but from the half to maximum, from half to zero it acts as the volume pot, it cuts completely Sound.
    To which this may be due, I did not see it clearly.
    I use the 3dpdt version without mod and exact pots to those indicated.
    thanks in advance friend

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    Replies
    1. Double check that you don't have a faulty 1k resistor from pin 1 of the fuzz pot to ground. Sounds like it's just shorting to ground. Or if that's not the case, try increasing the value of that resistor. It's what's setting the minimum fuzz level.

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    2. Ok I will try and inform you
      Thank you very much but in quick response and great work.

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  25. Hey there. I'm having trouble trying to figure out the wiring for the 3DPT and the DPDT. On each it says Fuzz In and Fuzz Out. Are those coming from and going to the "in" and "out" of the footswitch? And is the Input on the DPDT coming straight from the tip of the input jack? And is it also going to the input on the footswitch too?

    Sorry, I have everything populated on the board but it seems I've hit a roadblock here.

    Thank you!

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    1. The effect input is lug 2 of the Plexi/Velvet DPDT. That would go to your 3PDT footswitch or whatever method you're using for bypass. The connections in the switch diagram go to the correspondingly labeled pads on the circuit board. The exceptions being Fuzz In and Fuzz Out. These are just connections made between the Plexi/Velvet DPDT and the Fat/Tight 3PDT. Hope that helps.

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  26. Hi!
    Could somebody please let me know how to bias the J201s and how to do that? Negative to ground, and where does the positive DMM lead go to? Which (voltage, I suppose) value do I need to bias it to, and which pin shound I measure it at?
    Thanks in advance!

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    Replies
    1. Set your DMM to measure DC voltage. Plug your circuit board into a +9v supply and put the negative lead of the DMM to ground. Place the positive lead to the drain of Q2 and adjust the lower left trimmer till you around 4.5v. Repeat this process with Q3 and Q4 and their respective trimmers (Q3 lower right trimmer, Q4 upper right trimmer). Now run guitar signal through the effect to an amp and fine tune the trimmers if need be. I'd recommend doing this before boxing up the effect (rock it before you box it as the saying goes).

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  27. Thanks! Actually, the bigger question is the wiring, at least for me.
    I made a drawing of my understanding of how all wires and switches should go, but I can't see an option to attach it. Is there an e-mail address I can send it to?

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  28. I’ve cannot get this one to work. Wiring not a problem. The issue is the trim pots will not bias transistors at all. I always test pcb for shorts before populating and that’s not the problem. I’ve checked all parts and have tried 4 different 386s any ideas?

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  29. Should lugs 1 & 2 be on the same trace going to the drain on tranny ?

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  30. After over 100 pedals you'd think I would know better. A 1m resistor is not a 1K resistor and when you use 8 of them no wonder things don't work.

    Great pedal!

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  31. i was wondering where do you find these Schematics to go off of? im trying to bread board these and so far i can only really understand the ones that include a link to the schematic. does anyone have a schematic for this pedal?

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