It was the BS250 mosfet, as I suspected, see the LED switching drawn by Bernardduur in the already linked OCD tracing thread. At some point it got either a voltage spike or a static charge, and it was open all the time, letting voltage through to the LED. I have simply rewired the LED so that the fo...

Here's the complete schem: https://www.freestompboxes.org/viewtopic.php?p=26198#p26198 Thanks, I'll check it out. I'm very much inclined to leave the whole transistor thing out for the LED switching. I guess it is some kind of anti-pop measure, but honestly I never had LED popping issues, especiall...

Thanks for your replies, but unfortunately not The LED functions ok, so does the footswitch, I have measured both.

Dear All, I got a Fulltone OCD v2.0 for repair, the issue is, that the LED is all the time on, no matter where the footswitch or the bypass mode switch are. Also the LED seems to be quite dim. I have opened the box, and saw, that C14 is missing, however I have seen other pix on the internet with tha...

Hi Baja, A great one, thanks a lot! Some questions though... Is there a reason you made the input buffer out of a jfet instead of using IC1b for this? Also I'm thinking about making this one the preamp of a Class D poweramp I've seen on ebay. I would use a switching powersupply for it (again from th...

Hi All, Resurrecting this old thread... I'm trying to get this cracked. I have mailed Digitech, but the factory schematic of the reissue is not available for end users yet. Checked Bernarduur's schematic against the old version's factory schematic, and it is pretty much the same except for the flip-...

If anyone can provide high-res pictures of the top and bottom possibly with the component values (especially the caps and pots) then I would try to trace it...

I used my own pcb layout and I have built the newer version with the Presence control and not the old two-pot version. As I see from my schemos they are quite different in this regards: the old version connects to vref also on the non-inverting input with a 220k resistor.

@Frank,
Yes, that's how I built it the second time. I didn't find it exceptionally good, but it is certainly a very usable overdrive.

@Miro,
Thanks for the info. I didn't have the sqealing problem with the Hot Cake, but it is a nice info. I doN't know though why this is happening

What comes to redundancy, i'm not sure if one extra resistor at BOM is worse than not having the two dividers completely isolated from each other. I've built the Wampler Ecstacy with a common vref and the sound was crap. Then I' built it with separate dividers as in the original and the sound was t...

Time for me to contribute too: created a layout for both SIP and DIP packages. It is not verified yet.

Had the time to fiddle around with it today, and now it is ok. The following changes were necessary: 1) Changed R2 to 22Ohm as on the schematic 2) Changed both C5 and C6 to 100pF. Actually anything below 220pF will work, I hear some difference in the amount of distortion between 220pF and 100pF, but...

Thanks a lot for the schematic and the layout both. I've built the effect based on the layout provided by mirosol, but it does not work. Actually the signal passes through, but there is no distortion whatsoever. The volume pot works (no wonder), the tone contol has a subtle effect, but the drive kno...

Hey Everyone,

Sorry to revive a somewhat older thread, but the linked topic only has the Wampler book for intermediate/advanced and the "How to mod pedals" books. They are both excellent, but I'd be interested in the beginners book too if someone has a source for that...

Thanks!