Here’s a vero layout of the Fulltone OCD based on a schematic by tuemmueh of freestompboxes.org. This particular one corresponds to revision 3, but you can change this to revision 1 or 2 by changing a few values (according to the schematic).
I built the circuit today. Swapped the “Drive” and “Tone” pots compared to the schematic, and I’m now very happy with the result.
Update (08.11.2010): Having heard a lot of praise I wanted to try the Fulltone OCD overdrive pedal myself. It’s certainly a good overdrive, but haven’t yet decided whether I like it. Regardless, it was fun to build!
I didn’t have a TL082 in my parts bin so I substituted a TL072 instead. Will give the TL082 a try once I get a hold of one.
I keep thinking I want to find a better way to mount the circuit boards inside the enclosures. This time I put a pair of double-sided tape pads on the back of the “Tone” and “Volume” pots and fixed the underside of the board to this. It works nicely and is a step in the right direction, I think.
Update (20.10.2011): Fixed dead picture links.
Mine works fine and sounds good. The only problem I have is a small range of Tone pot. Even when it all the way down it still sound kind of bright. It’s even brighter when I turn it up so it works. But should be darker when when it’s turned down. Any ideas?
I can’t help you with any mid boost mod, sorry. You could try the forums (links on right-hand side), or you can breadboard the circuit and do some experimentation.
It works great!
but it has not so much mid frequences…
how can i add a little more mids?
what mod do you suggest?
thanks.
Rob,
Poor choice of word perhaps, but by swapping the pots I (seem to recall) meant swapping the wires going to the #1 and #3 lugs, i.e. making the pot work in the opposite direction. Just a convenience change that has nothing to do with the sound of the unit, just how you interact with it.
If yours only pass clean a clean signal you’ve got a mistake in there somewhere. My best suggestion is to check out the “debugging” section for some guidance and tips.
Hi, I was wondering what you mean by swapping the tone and gain pots??
8
I’ve built this layout but mine doesn’t distort, I just get a clean boost?!
The 2N7000s are used for clipping and not normal operation, so your substitution will probably work fine. Just mind the pinout.
Hi Harald,
Can I swap the 2n7000 for bs170 or will it sound too different.
Thanks
Hi nikos,
Can’t see any reason it shouldn’t work so go ahead. Give it a try 🙂
the ocd with jrc4558d is work?
The output signal is taken directly from the volume pot lug #2. There’s a list of additional required connections in the lower right-hand part of the layout.
where is the output go? or is there something i missing?
I would probably not hear the difference with mica caps, but others might so it’s really up to you 😉
Thanx. I found out I had a faulty transistor q1. So I replaced it, also I upgraded C11 with a tantallum 10uF. Now it sounds really great. Lots of sustain and transparancy, it is so versatile en dynamic. Though I must admit it’s a tad bassy with my SG model, buth nothing a EQ can’t manage. Would it help to swap the 220pF’s with silver mica ones?
I kicked out my 1983 DS1(bwoah) and upgraded my pedalboard with my OCD clone!
Hi Johannes. Depends on what your definition of low volume is, but you should definitely get more than unity gain from this effect. Hard to say what the problem is, really, as it can be any number of things, so I can only encourage you to do basic debugging. Since you’re getting sound it can’t be that bad, but check your trace cuts, look for solder bridges and make sure you’ve used correct value components. Sorry I can’t be of more help.
Hi I built this thing last week, and it sounds great, but volume is very low. I triple checked every item twice, any ideas?
Hi Shawn. I do have a couple of general wiring illustrations for true-bypass wiring and that sort in the “schematics & drawings” section. Hope those are of help to you.
nevermind. I figured it out.
Harald,
Thank you for the plans. I am new to this, but am giving it every effort. I was wondering if you had a schmatic for how to wire the rest of the pedal, not just the vero circuit portion. i.e.(where to the wires go on the pots, switches, etc.) Thank you!
sorry forgot to mention all caps are rated over 25v
Awesome! I built this last night and it sounds great!!! One question though, will it be ok to run on 18v? Thanks again.
Mine is a tad muddy too, but I still like it. If you’re going to use a tantalum you only need to swap C11 on my layout. The two other electrolytics are used for supply filtering and not in the signal path.
Hi Harald!
To begin with i just wanna say thank you for all your amazing designs, i really appreciate them!
I did this one and it sounds beyond awesome, but for some reason i find it a bit muddy, might just be me.
After some reading on the web i found out that tantalum caps might be a bit brither soundsing and better on high freqs.
Do you think changing some of the three electrolytic ones for tantalum would impact the sound in a good way or?
Which one would be the first of them to try swapping out then?
Once again, thank you for your amazing work!
We all make mistakes all the time. Happy to hear you sorted it out 🙂
Hi Harald,
I’m a dumb. I corrected a mistake last night and now the pedal rocks.
Thanks a lot.
Andrea
I Harald,
I built mine last night and it was a complete disaster.
I do not want you to debug my unit online, of course, but the symptoms are quite strange.
Volume works, while turning the drive affects the drive only in the midrange: low or high drive levels make the sound oscillate…?
I will double check everything, I was just wondering, is it possible to have bias values at least for the two transistors and maybe for the TL082? Thank you very much
Andrea
Have you looked for shorts around the related components (R10, R12)? Are both tracks properly cut where they should? Have you double checked your wiring? Do we agree on how switch lugs are numbered (#2 is center)?
Hmm… that makes me sad… I wonder why mine doesn’t.
I have an actual OCD Ver1 and this one sounds similar, so I know what its supposed to do, but it doesn’t do anything.
Mine has two distinct flavors.
I got this thing wired up and it sounds great other than I hear no difference with the toggle switch in either position… anyone else experience this?
I built one of these up yesterday and wired the pots in reverse like a fool. I switched it around and ended up with a non working volume control thats on fully open.
However it sounds great and i shall sort the volume issue shortly.
Has anyone else found its a touch noisier than most OD’s?
THanks for a great layout
T
I put this together last night, and it sounds great (I used a TL082). Thanks for the layout!
It’s me trying to explain I had the potentiometer wiring reversed in the earlier version of the layout. It’s just for reference; the layout should be good to go.
“Swapped the “Drive” and “Tone” pots compared to the schematic”
What does it mean? Thanks
Andy
Good suggestion, Ron. I personally tried a couple different opamps (not any OPAs) and could hear very little difference, but I’m sure some work better than others. I left the 82 in there since it’s the one used in the actual unit.
I think better results can be achieved by swapping TL082 with something from OPA series.
I just made one of these, its absolutely wonderful. I can’t thank you enough for the vero layout.
Cheers!
Hi. planning to make one of these. can you tell me where can i find the schematic for 1st version? wanna give it a try?
You’re right. Thanks for spotting this, Sven.
Hi Harald,
I am not sure but, I think there is little mistake in your OCD layout. The Q1 pinout should be SGD form top to bottom and Q2 DGS.
A BB-Preamp layout would be very fine 🙂
Hilsen
Sven