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Kind of late reply but here's some info, hope it helps.
http://www.tubeampdoctor.com/images/File/BTDR-3%20DIGI-LOG%20REVERB%20MODULE.pdf

Well I tried some other things with this circuit and none completely got rid of the whine. So I put and old BOSS tubescreamer I had laying around before the boneyard and that also did not completely remove the whine, so not even a buffer in from gets rid of it on mine. I might have to do the half gain mod for this to work but I did want the high gain of the original to work   Well I'm sorry I couldn't find the real cause of the problem. I don't if I should spend any more time on this or just put the buffer and be happy with the higher range(b4 oscillation occurs) I can get out of that or spend my time on a different layout instead.

Well thank you for all the info mgwhit and all others who have tried to solve the problem.

Hello guys,

I posted a while back I saying I was going to look into it and I just got my pedal back from my friend so I apologize for the delay and I just started looking into it earlier today.
So far it looks to be crosstalk from the high gain section being routed too close to the input (R4/R1) and that whole trace passes below all the input components all the way to pin1 of the IC(LF347). So I took out all input components(RPD,R1,R2,C1) except C2 and wired the input directly to that and it took the whine away until I set the vol to like 2-3 o'clock then it started to come back again.
Also looks like it needs shielded input wire.
So next I placed R1 soldered to one side of C2 and it still kills the whine but only until the vol reaches 2-3 o'clock position.
I'm going to experiment a lil more later and post my findings. If it's not getting anywhere after that I'll just etch my own PCB to see if that solves it. I would like to build this without the extra buffer circuit but it might not be worth the effort considering how simple it is to just add a buffer in front of it as it has been mentioned here. I'm just determined to find out why it's oscillating I guess...lol

Hi all, I'm new to this forum but I've been following a few threads and this one in particular as I have also built this pedal for myself recently. I used the original a few months ago and I loved it so I waned to make me this one.
Now I love how this pedal sounds but I have also run into the high pitch whine problem. I noticed that moving or touching dome of the wiring killed the whine. So I suspect it might be a layout problem. I let a friend of mine borrow it for two weeks and told him to roll off the treble in his guitar to temporarily cure it. I will work on it as soon as I get it back.
I don't know if you guys noticed that this pedal already has an input buffer according to the schematics. So it might be just a matter of adding a small bypass capacitor(47p or so) at the input or at different stages. I'll try some theories I have and post my findings. Usually high gain circuits as this should have a very short gain loop, so it might be the traces on the PCB as well contributing. If input and output traces are too close, that will cause all the feed back or oscillations.

Well sorry for the extra long first post. I just want to give something back to this great forum where I have learned so many different things.