Dark Rift Delay - Distortion/Fuzz in Wet Signal

absolvism

absolvism

Member
Hello!

I just finished building a Dark Rift, and everything seems to be working... except the repeated/wet/delay signal has a distortion/fuzz in it..

So the first pluck always sounds normal, but then all the succeeding delay signal has a very pronounced fuzzy/scratchy undertone to the whole thing. I've tried different amps and cables and it appears that it's definitely in the pedal itself. If I set the mix to 100% dry, there is no fuzz, it's just in the wet.

Besides pulling the whole thing apart and starting over, does anyone have any ideas or directions to troubleshoot that they might be able to help point me in? I can record example audio if that would help.

Thanks so much in advance,
Ellis
 
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Here's a picture of the wiring if it helps (not final final state- was just testing audio before finalizing).

I'm so bummed it's got the weird issue! Am really excited to give it a real shot.

rift-wiring.jpg
 
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Does the distortion increase with the number of repeats? Or do you hear about as much distortion when you only have one or two repeats dialed in?

Do you have other PT2399 chips you can substitute? If you do, it would be a lot easier to swap a few different chips in and out to see if it changes what you are hearing. I have had a lot of variation in the amount of noise and fidelity in those chips.
 
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The original note is clean, but distortion/scratchiness kicks in on the first firing of the delay signal and fades out equally to the curve of the delay signal fading out. If there is delay, there is like a 5% equivalent dirty "scratchiness" under the sound, pretty much mapped to the volume of the delay signal. I uploaded a quick example here - https://ellisedwards.com/content/DelayFuzz.mp3

Thanks for the advice about the 2399. I will order a couple more and see what happens.

I have checked all the joints and I don't see any solder bridges or bad connections anywhere. I had to get the sockets for the IC's from a surplus gizmo store- is there any chance it could be caused by a low quality socket or anything? They seemed fairly straightforward. I'm new to the DIY pedal world- does it look at a first glance that I'm using the right capacitor types for a job like this? Any other thoughts to troubleshoot other than replacing the IC?
 
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you can post a pic of the other side of the board and get feedback on any soldering questions that people have. it sounds like you have a working audio path, which makes me think the chip could be a noisy one. a cold soldered joint can degrade audio but it is usually more likely to drop signal level of not pass the signal.
 
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zgrav said:
you can post a pic of the other side of the board and get feedback on any soldering questions that people have. it sounds like you have a working audio path, which makes me think the chip could be a noisy one. a cold soldered joint can degrade audio but it is usually more likely to drop signal level of not pass the signal.
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Thanks for the feedback. I’ve found a lot online about similarly noisy/fizzy PT2399 chips and specifically from Tayda (which is where mine came from). Ordered some from Smallbear- hopefully they’ll be better!
 
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Vildhjuggah said:
Though you have checked the solder joints already for bridges, it looks like most of them don't have solder flowing all the way through AKA bad and/or cold connections.
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Do you mean on the pots and wires from this side of the board? Or do you mean on the caps and resistors etc? Should every ring/hole appear 100% filled always on the inverse side of the board as well? Sorry if these are really stupid questions.

If you mean the caps/resistors side- how would you address this at this point? Can I just attempt to reflow them all or do I need to desolder everything? Is it doomed?
 
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Too soon to jump to any conclusions about whether the parts are sufficiently connected on your board. The easiest thing to do right now is wait until your new PT2399 chips arrive and see if any of them sound better than what you already have in there.

If not, or if you want to keep checking out your work post the pic of the side of the board where the parts are soldered. It may be that you will want to put a bit more solder on your parts when building other projects, but for now you can use your multimeter to make sure the parts are connected on to whatever is called for in the schematic. IF you find a part that is not well connected you can reflow the solder and fix the issue.
 
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Well I can only see one side of the board so I cant comment on the other. But yeah its best to have it flow all or most of the way through so i'd say you should have put more solder/leave the heat on long enough for it to actually flow through. Which makes me think you have cold/bad solder joints in general. So it makes me think you should probably reflow most of them, but if they look good on the other side it may be a good enough connection that you should just wait for new chips as zgrav said and see if thats better.
 
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bschobs said:
absolvism - Curious, did you ever figure this out? Just got done troubleshooting my Dark Rift and have a similar issue.
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I am still having this problem. I am still waiting on a batch of new ICs from Smallbear to ship to test out if it’s a bad chip (which I suspect it is). After I posted a few days ago, I was informed that I may have some cold joints, so I went back and took it apart and fixed any jenky joints (there were definitely a handful, so I didn’t want to waste anyone’s time with a picture) and put it back together tonight and am still having exactly the same issue. So back to waiting on new chips. The original chip was from Tayda fwiw. After the troubleshooting I have a feeling a better chip will fix this but I can’t be for sure. Did you get yours from Tayda?
 
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Chuck D. Bones said:
Are you running guitar-level signals thru the Dark Rift or is the signal boosted before the Dark Rift?
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Guitar level signal, yes. It previously had a boost in front when I first got it hooked up and was troubleshooting, but tonight it was the sole pedal inline to the amp. Still fizz/distortion in the delay signal.
 
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Also - If I can ask a quick dumb side question to anyone that might be able to answer.. I accidentally had a 470nf cap installed in C11 for about 5 mins while I was doing this last round of testing before I realized it should be 4.7nf. I swapped it.. but should I be concerned that it did harm to the board or other components while live that short time?
 
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The wrong value for C11 won't hurt anything. In fact EQD screwed-up that part of the output filter and C11 does nothing. You could leave it out and the pedal would sound exactly the same.

The reason I asked about the signal level is the DR has a diode clipper (S2 & D3) in the feedback loop. A boosted signal could drive them to clipping.

I checked all the parts in the audio path (the ones I could read, anyway) and they're all correct. Like you said, probably a bad PT2399.

Did you verify that +5V is 5.0V?

Those stamped-pin sockets are not the best. After a few in/out cycles the sockets can get loose.
 
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I was putting guitar level signal as well. Don’t really get the clipping when I am playing softer. Actually played the thing for an hour last night and enjoyed it, but was limited in what I could play.

and yes my pt2399 was from Tayda too. Ordered some from SB last night.
 
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bschobs said:
I was putting guitar level signal as well. Don’t really get the clipping when I am playing softer. Actually played the thing for an hour last night and enjoyed it, but was limited in what I could play.

and yes my pt2399 was from Tayda too. Ordered some from SB last night.
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Yeah same, definitely worse the harder played.
FYI- I put in a SB order on the 5th and as of yesterday they said they were still working through an avalanche of 200+ orders ahead of mine from that date. Just a heads up
 
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