A biggie but it will fit a BB enclosure without battery. If you think this is to big for vero, Deadend Fx have excellent PCBs for this circuit and many other cool designs.
Schematic is avaiable HERE.
A biggie but it will fit a BB enclosure without battery. If you think this is to big for vero, Deadend Fx have excellent PCBs for this circuit and many other cool designs.
Schematic is avaiable HERE.
Thanks for doing this one! Wanted one of these for ages. I'm getting more of a tremolo type sound and not as prominent resonance as in the demos but going to assume I've screwed a value up somewhere - controls work as expected so likely user error on my part. Will debug and hopefully be able to verify.
ReplyDeleteI built this last night too and got the same results as you. LFO and pots works but there is something missing....reverb and resonance. I compared the layout and schematic until my eyes bled but I can't seem to find any mistakes. I suspect the problem is somwehere around the BBD ICs and transistors since it looks like a feedback path betwwen the op amps.
DeleteOh, well, I'll put this aside for a while and take another look later with fresh eyes and clear mind...
I've printed the schematic out and compared it and can't see any differences to your layout. I'm wondering if maybe there's a value off somewhere that's choking the effect. Bridged the 220k on a whim and it did nothing, complete guess though. The build doc mentions turning the trimmer until it self oscillates but from what I understood that was setting the vref for the opamps so apparently I know even less than I thought!
DeleteJust chiming in to say that I'm having the same issue with the actual DFX board. Modulation section works fine, only a slight hint of resonance/echo with the knobs dimed.
DeleteCurious - which BBD ICs are you folks using? I ordered mine from Smallbear, 2 sets to be safe, no change with either.
No NOS chips in mine, I have V3102 and V3702 by Coolaudio in mine. They are supposed to be interchangable but you never know...
DeleteI used the same coolaudio chips, tried two different sets and no dice with either.
DeleteSomeone over on DIYS was having the same issue and cracked it—swap in a VTL5C2 in place of the 5C3 and that should fix the issue, or play around with LEDs and LDRs until you get the magic combo.
DeleteGreat news! I need to order some VTL5C2s then. Hopefully the new ones from Xvive works...last time I checked the NOS ones was for 22 EUR.:-/
DeleteThe LCR-0203 mentioned in the build doc should also work, I think that's what DFX used to verify the build.
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ReplyDeleteI got mine finally working. Culprit was the 3207 as I suspected, very likely fake- I had 5 of them, all garbage. I recently got a new batch and the cavern started to sound... I tested a few ldr/led combinations and the sound was not very ok, but the effect was there. I finally tried a SR-VTL chinese vactrol (no marking on it, but it has a 450k resistance in dark), and the circuit came to life. It is a nasty echo, it will definitely go in a box soon. So layout is verified imo. Cheers!
ReplyDeleteWow. Thank you for doing this. It really made my day. Tagged it. Waiting for some VTL2C5 to arrive but I'm tempted to to try out some LDR/LED vactrols now... Fingers crossed crossed for that 3207 isn't fake.
DeleteJust to +1 this, I finally got a pack of new vactrols from aliexpress last week and problem solved. It was definitely that xvive VTL5C3. I went with the LCR0203 but ordered the 0202 and VTL5C as well, just in case.
DeleteThx fuzzhead for the beast!
ReplyDeleteI try to do it with time expression jack like in deadend fx project, but i don't see in his schematic what is connected with jack's RSW, SSW and SLV. Any thoughts?
ReplyDeleteWhat a strange pedal!!! I added the expression pedal jack connections, much more entertaining. Tip to V31 and Ring to AB30
ReplyDelete