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.
Amazing! I´ll try it!
ReplyDeleteWhere is the tranfer? Thanks
ReplyDeleteIt's in the transfer library tab at the top of the page in the Fulltone folder.
DeleteThanks bro!
DeleteNice project! I'll try it...
ReplyDeleteJust one doubt... Where to connect the 3rd pin of tone switch? To ground? Can you post the schematic?
Thanks a lot!
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.
DeleteAnd the schem you can find pretty easily if you google it.
DeleteUnderstood! Is an on/off switch, just open or closed contact... Thanks a lot!
DeleteHey 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?
ReplyDeleteThanks!
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.
DeleteYou 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.
ReplyDeleteThanks for another great layout!
Threw me right off the first time I plugged it in!
Deleteis there a reason why the tone pot is treble counter-clockwise ?
DeleteTheres 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.
ReplyDeleteKeep up the great work!
Oh weird. Wonder how I managed that... Fixed now. Thanks for catching that.
Deletehttp://robotmonster.nl/2016/09/30/pentagram-2016-eurotour-poster/
ReplyDeleteI 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
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.
ReplyDeletefrom 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.
ReplyDeleteYes you can use BS170s, just rotate them 180º from whats shown in the layout.
DeleteHere'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.
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...
ReplyDeleteHahaha! Welcome to club. I said I needed to take a break from building right before I started this blog. :D
Deletei 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
ReplyDeleteIf 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! ;)
DeleteI built v3 and got only clean sound. Idea(s)?
ReplyDeleteturn the gain up
DeleteJust 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.
ReplyDeleteShould be tone pot leg 1 to ground and legs 2 and 3 to the 47nF cap? Or there is no difference?!?
Shouldn't be any difference.
DeleteGood Day. Send please layout project to ledozzy@mail.ru
ReplyDeleteThank you!
Where is fucking BYPASS паять?
ReplyDeleteпосмотри раздел http://effectslayouts.blogspot.com/p/general-layout-notes.html
DeleteHey 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.
ReplyDeleteI 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!
Keep probing. Could be a bad gain pot.
DeleteI 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
DeleteHi,
ReplyDeleteThanks 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
I used one of the ones floating around the net. Don't remember which... The 47µ cap is for power filtering.
DeleteThanks 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!!
ReplyDeleteNice!
DeleteIt´s verified. Made v3 and it sounds great, but the tone control is not clockwise, but no problem.
ReplyDeleteThank you =)
I've got some questions:
ReplyDeleteWhat'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
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.
DeleteCan I run this pedal on 18V?
ReplyDeleteAs long as you use the appropriately rate components it should be fine.
DeleteI built V2 with LED clipping option. Sounds badass. Thanks for sharing this layout!
ReplyDeletewere did you place the LED clipping? im planning too. tnx in advance
Deletei built the v3.. sounds awesome... i love it
ReplyDeletehello ! why the v3 is better than others ?
Deleteall versions are great depending to the taste of the player..version 3 sounds mre agressive for me .
DeleteHello is somebody know if its possible to use spdt to replace spst ?
ReplyDeleteI think it, ok if i use just 2 lugs of the switch ? please help me i'm not sure
and really i can't find toggle swishy spst with 2 lugs
Yes, a SPDT will work just fine. Just ignore the 3rd lug.
DeleteDisculpen en el D1 que dice Jumper de la versión 2, que va donde dice Jumper
ReplyDeleteHolà,
DeleteDépende de la version que QUIERES construir !
La version 1, 2 & 3 no utilisa diodes PERO une jumper ! La version 4, hay que PONER la diode 1n34 !
No sa y si es Claro por ti ?
Jumper significa puente, o sea, un cable
Deletehi guys.. ive built this following you diagram..and im having trouble with the pop sound whenever i turn the switch on and off (3pdt).. before the sound is noticable i chained it to my multi effects.. from there whenever i switch the pedal on and off the pop sound is very loud..pls anyone can help.. TIA
ReplyDeleteCheck this out:
Deletehttp://www.muzique.com/news/pulldown-resistors/
The vast majority of my layouts have a pulldown resistor at the input, but sometimes it's necessary to increase the value or add one to the output. And sometimes it's just a 3PDT that likes to pop.
iv tried adding a resistor (1M) between the input wire and ground sleeve but nothing happens.. still had the pop sound.. and it adds some buzz..
DeleteSince there's already a 1M resistor to ground from the input, adding another 1M teffectively makes a 500k pull down resistor. Try increasing the value of the resistor right next to the 22nF input cap to like 2.2M. But also try adding one at the output of the circuit.
Deletethanks man..ill try 1st adding 1M on the output..im sorry i miss reading that part on your comment..ill let you know if it works.. hopefully.. fingers crossed..
ReplyDeleteVerify?
ReplyDeleteYes it is verified.
Deleteonce again project completed successfully !!!
ReplyDeleteyou can mark this as verified, I made version 3 and it finishes identical to the original one.
your website is a treasure to me.
thanks from Brazil !!!
Just finished up V3 last night (no issues) and like it so far (still getting used to it).
ReplyDeleteIs there any way to reduce the bass a little? That’s the only adjustment I’d like to make.
Thx, and keep up the great work!
- Buck
Can I use a TL081cp instead of TL082 ?
ReplyDeleteNo. A TL081 is a single opamp, and the TL082 is a dual opamp. You can use another dual opamp like the TL072 or JRC4558 if you like, but it will sound a little different from a standard OCD.
DeleteOk, I just noticed 2 diferences between this project and other in the link bellow, lack of R2 220k in Ver3 and a 10uF in the place of 47uF in all versions. Does it make any difference? What is the original v3 layout? (This one also have the 1N4001 for reverse current protection). Thanks! http://tagboardeffects.blogspot.com/2012/02/fulltone-ocd-all-versions.html
DeleteThis comment has been removed by the author.
ReplyDeleteHi! I know that this thread is a bit old but maybe someone still reads it :) I got the original OCD version 1.4 and what I can see inside are three 10uF elecrolitic caps and one additional 1uF tantalum cap (marked C8).
ReplyDeleteIt looks like this: https://c1.staticflickr.com/4/3182/3120464055_ebe9d4182e_b.jpg
I can't see any 1uF cap on any of layouts above - where should it go if I wanted to add it to my build?
This comment has been removed by the author.
ReplyDeleteI follow you, but the result is not the same. Both devices like you Please help me.
ReplyDeleteThe tone pot is reversed
ReplyDeleteVerified. Works well.
ReplyDeleteWork with charge bomb 555!!!
ReplyDeleteGreat sound!!!
Verfied.. made v2 with all linear pots works cool
ReplyDelete