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.

Wednesday, June 22, 2016

Fulltone OCD

I've been meaning to redo the OCD with proper board mounted pots, so here it is. It's a development on the Voodoo Labs Overdrive, with MOSFET clipping and a simple tone control. Fulltone has made a few versions of this with a few minor changes over the years. They're all mostly the same, but the biggest differences is in the pot values. Below is a partial bill of materials outlining the differences between the first 4 OCD versions, along with a couple value changes to mod the bass response.


42 comments:

  1. Replies
    1. It's in the transfer library tab at the top of the page in the Fulltone folder.

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  2. Nice project! I'll try it...
    Just one doubt... Where to connect the 3rd pin of tone switch? To ground? Can you post the schematic?
    Thanks a lot!

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    1. The switch is just a SPST, so only 2 lugs. You can use other switches, (SPDT, DPDT) but you only need to connect to the first 2 lugs.

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    2. And the schem you can find pretty easily if you google it.

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    3. Understood! Is an on/off switch, just open or closed contact... Thanks a lot!

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  3. Hey dude! Is there any difference between capacitors showed in green from those showed in cream color on the layout? Green = Polyester and Cream color = Ceramic, is that right? Will it sound different if I put all the same, I mean, all ceramic capacitors for these?
    Thanks!

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    1. You are correct. There probably won't be much discernible difference if you use ceramics for everything. I've used ceramics in a lot of builds with good success.

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  4. You can call this great sounding baby verified. I made a v3 and it sounds awesome. I will switch the connections on the tone switch though to make it more intuitive with treble clockwise instead of the other way around.
    Thanks for another great layout!

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    1. Threw me right off the first time I plugged it in!

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    2. is there a reason why the tone pot is treble counter-clockwise ?

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  5. Theres a 10k resisitor missing from between Pin 1 of the TL082 to the Drain of one of the 2n7000s on the PCB layout. Its on the perf layout.

    Keep up the great work!

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    1. Oh weird. Wonder how I managed that... Fixed now. Thanks for catching that.

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  6. http://robotmonster.nl/2016/09/30/pentagram-2016-eurotour-poster/
    I just finished this tourposter. The circuit in the wolf's cheek is based on photos of my build of your OCD pcb, with some liberties taken ;-)

    Keep up the good work

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  7. can't find any 2n7000 in my local area, is there any substitute for it? preferably the BCxxx series, since I have a bunch of them in my junk box.

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  8. from my reading you can use bs170s but you have to flip them around , different pinout. Can anyone confirm? From what the demos ive listened to on youtube seems like ppl like version 1 the best, either way has anyone tried differnt versions, im curious because i rarely see auio log pots for tone, just so happens i have A25k pot, but from there closest linear pot i have is 100k. Id like to build this, im gonna go ahead with pcb. I dont have really anything else to order, so id prob go ahead and get all new pots the right angle ones.

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    1. Yes you can use BS170s, just rotate them 180º from whats shown in the layout.

      Here's a trick for PCB mount pots. I use thicker component lead cutoffs (generally from film caps or 1N400x diodes) and solder them to regular solder lug pots straight down. Bam–PCB mount pot. you can also use some stripped solid core wire instead of cutoffs.

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  9. what about the 220pf caps? seems like i just keep buying parts, yet i am always missing 1 key value to build what i want to correctly. Ive got some 100pf ceramics, and some 470pf green films, from reading around i cant find much other than one person said it fixed his problem of alot of noise or feedback using 470pfs and someone else who said it reduced the gain a ton and didnt sound like an ocd... As much as i love this hobby its starting to drive me crazy, and i spend more time examining schematics and gut shots than i do actually playing guitar, and like 2 days after i build something its like ok whats next, prob need to take a break from building...

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    Replies
    1. Hahaha! Welcome to club. I said I needed to take a break from building right before I started this blog. :D

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  10. i know i could put the 100 pfs in parallel with each other and get 200pfs and thatd prob be close enough given ceramics tolerance just wondering your thoughts on what 100pf vs 470pf what each one would sound like, i guess this pedal is appropriate place to do one more build and then give it a rest, if im gonna go through etching and drilling and all the work i just hate to be putting couple cheap ass caps in parallel and then it looks junky, im sure you understand...it really has given me ocd wanting everything to look good as well as sound good, seems to be the nature of the hobby

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    1. If it were me, I'd just stick the 2, 100p caps in parallel. You could always throw some heat shrink around them to tidy it up. Either way, it's still gonna look tidier than vero! ;)

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  11. I built v3 and got only clean sound. Idea(s)?

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  12. Just one question, on the picture, tone pot legs 1 and 2 are connected to ground and tone pot 3 is connected to the 47nF cap.

    Should be tone pot leg 1 to ground and legs 2 and 3 to the 47nF cap? Or there is no difference?!?

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  13. Good Day. Send please layout project to ledozzy@mail.ru
    Thank you!

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  14. Replies
    1. посмотри раздел http://effectslayouts.blogspot.com/p/general-layout-notes.html

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  15. Hey buddy, i just finished my OCD V4 but i have a trouble in the volume. It has a too small volume - with the volume pot all open i have the volume equal the bypass volume. I already checked the layout a plenty of times and not found any trouble or mistake. I only replaces the 1n34a for a 1n270 - but it should not cause me any trouble.
    I checked that in pin 1 i have a huge good sound from the pin 1 until the gain pot lug 1, but in the lug 2 i have a too small volume sound. But obviously the pot is not the problem.
    Have you an idea about why it happened? Thank you, you rocks!

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    1. Keep probing. Could be a bad gain pot.

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    2. I already tested the pot it's okay. I found another guy with the same problem on diystompboxes.com forum. I will just continue it tomorrow if you have any advice let me know, please. Thank you for your attention :D

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  16. Hi,
    Thanks for this layout !!
    What schematic did you use for this layout ?
    I've never seen a 47µF caps in any different versions of the OCD.
    And it seems that the 47nF caps is 100nF for Rev1.

    But maybe I'm wrong

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    Replies
    1. I used one of the ones floating around the net. Don't remember which... The 47µ cap is for power filtering.

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  17. Thanks bro!! I just finished mine but I made an excellent mod, put a switch in the 1n34a diode position and I can change between v3 and v4! It's an amazing pedal and amazing layout! Thanks so much and best wishes from Mexico!!

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  18. It´s verified. Made v3 and it sounds great, but the tone control is not clockwise, but no problem.

    Thank you =)

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  19. I've got some questions:
    What's the "4100" unit? (next to the tone pot.) Is it a diode? Is there any file about OCD like for ex. about RAT (BOM, transfer, drilling)? And the last one: When it goes ito HP mode: when spst connects two pins or not?

    Thanks for the answers!!! :D

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    1. It's a rectifier diode to protect your circuit in case of accidentally plugging a power supply with a positive center. 1N4001 / 4002 / 4007 / 400x should be fine. You may omit this if you are sure to have only center negative power supply. When in HP mode, SPST is left open. As for other questions, google is your answer. Lots of info on the web.

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  20. Replies
    1. As long as you use the appropriately rate components it should be fine.

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  21. I built V2 with LED clipping option. Sounds badass. Thanks for sharing this layout!

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