Dark Rift Delay issue

[Rixroxx]

I built 6 pedal pcb projects this last two weeks, including the EQD sea horse, which sounds great.

However, I was unsuccessful with the darkrift delay. It powered on and there was full nice clear sound in effect position, however, there is no delay sound. I checked all my pots and it seemed they are okay. I also tested my three PT2399 on the EQD sea horse and they were working good.

I noticed on the pdf file of darkfrift that the direction of the D2 and D3 are in the same direction but on the actual PCB they are marked in opposite. Could this be the issue why I'm not getting a delay sound?

 

[KR Sound]

They definitely go in opposite directions, you must have some other issues going on.

Let’s see the rest of the board. Make sure C8 is 1n and not 1u like the other three.

 

[Rixroxx]

They definitely go in opposite directions, you must have some other issues going on.

Let’s see the rest of the board. Make sure C8 is 1n and not 1u like the other three.

View attachment 41067

Hi @homebrewtj, thank you for your reply.

I was sure i used 1nf on C8 during the building of the project. i can get very good audio sound in effect position except that there is no delay sound coming out. I tested the PT2239 that i used on my other project (sea horse, the one on the right picture) and the IC was working. I also replaced the LM324, i have plenty of it.



I have other projects that i built and tested working very good these last two weeks. So i can humbly say i am good on my soldering.

 

[KR Sound]

Everything looks right to me, value wise. Is the top right 833 seated properly? That’s the only thing that looks odd to me.

 

[Rixroxx]

Everything looks right to me, value wise. Is the top right 833 seated properly? That’s the only thing that looks odd to me.

I checked the legs of the op amp meant for 833 and they are seated well. Actually i used NE5532P, but i tried also an LM833 the one used on my Angry Andy plus and it was working. I believed the LM833 and TL072 are op amp that give the sound to the circuit. Even without the PT2399 the circuit will output a sound. I still need to find time if i can get more PT2399 on the local electronic store here.

 

[zedfyrom]

Hi, I'm getting the exact same problem. Have you managed to resolve it?

 

[zedfyrom]

The pedal it's working but it's giving just a single repeat. Well actually it's not just a single repeat but the feedback is pratically inaudible except for the first, still low, repetition. I can even tell the modulating it's working but by now this thing it is a useless pedal. I really don't know what the issue can be. I already tried to substitute the chips.
3 things to note in the photo:
I swapped the lm324 with a tl074 to see if i can get any change, but nothing.
D2 it's in reverse to what the pcb tell. I reversed it to try to align to what the build guide says but that still not was the fault.
In the place of R7 there are 2 resistor in parallel that i tested to be 8K (required value is 8.2k, but i don't think that's the problem again)

Please note that the mix and the feedback pots are maxed out in this audio sample.

https://soundcloud.com/gabriele-pala-404092013%2Fdark-rift-delay-rotto-del-dio-melanzana

And here are my voltage:

Pt2399

Pin1: 4.5
Pin2: 2.25
Pin3: 0
Pin4: 0
Pin5: 2.63
Pin6: 2.25
Pin7: fluctuating (average 0.32)
Pin8: fluctating 0.65 to 0.66
Pin9: 2.25
Pin10: 2.25
Pin11: 2.25
Pin 12: 2.25
Pin 13: fluctuating 0.01 to 0.02
Pin 14: 4.5
Pin 15: 2.25
Pin16: 2.25

Tl074:
Pin1: 4
Pin2: 4
Pin3: 2.2 then start to drop
Pin4: 0
Pin5: 3.93
Pin6: 4.02
Pin7: 4.02
Pin8: 8.05

lm833:
Pin1: 2.26
Pin2: 2.26
Pin3: 2.20
Pin4: 0
Pin5: 2.22
Pin6: 2.25
Pin7: 2.26
Pin8: 8.05

lm324:
Pin1: oscillating from 2.5 to 5.something
Pin2: 4
Pin3: 3.92
Pin4: 8.05
Pin5: oscillating like pin 1
Pin6: 3.6
Pin7: oscillating from 1.something to almost 7
Pin8: almostl ike pin7
Pin9: like pin 1
Pin10: like pin 1
Pin11: 0
Pin 12: 3.9
Pin 13: oscillating fom 3.8 to 4.2
Pin 14: oscillating from 1.6 to 6

 

[Zennmaster]

Let’s see the rest of the board. Make sure C8 is 1n and not 1u like the other three.

From the distant future:

That wasn't the OP's issue, but it was mine. Problem solved, and sweet delay is delaying.

Thanks for the heads-up!

 

[chris.knudson]

My initial guess would be the PT2399. But if yours is working in another pedal, that isn't your problem.

This might sound like a dumb question -- and trust me, I wouldn't ask it if I hadn't made this mistake myself -- but none of you pictures show the PT2399 populated. Was it in there when you did the test?

I only ask this question because I once built a blues breaker, tested it and it did not work. Just when I was about to throw in the towel, I realized that I never inserted the ICs.