# Dark Rift Delay - Distortion/Fuzz in Wet Signal



## absolvism

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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## absolvism

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.


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## zgrav

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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## absolvism

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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## zgrav

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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## absolvism

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.


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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## BurntFingers

Is this at all time settings? The pt2399 does degrade over about 250-350ms depending on the specific chip.


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## absolvism

BurntFingers said:


> Is this at all time settings? The pt2399 does degrade over about 250-350ms depending on the specific chip.


Yeah, there is an obvious low-volume fizz at all settings- I recorded it in the audio file I linked to a couple messages back


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## Vildhjuggah

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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## absolvism

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.


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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## zgrav

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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## Vildhjuggah

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

absolvism - Curious, did you ever figure this out?  Just got done troubleshooting my Dark Rift and have a similar issue.


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## Chuck D. Bones

Are you running guitar-level signals thru the Dark Rift or is the signal boosted before the Dark Rift?


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## absolvism

bschobs said:


> absolvism - Curious, did you ever figure this out?  Just got done troubleshooting my Dark Rift and have a similar issue.


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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## absolvism

Chuck D. Bones said:


> Are you running guitar-level signals thru the Dark Rift or is the signal boosted before the Dark Rift?


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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## absolvism

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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## Chuck D. Bones

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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## bschobs

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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## absolvism

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.


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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## absolvism

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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## bschobs

Yeah I've seen others say the same about SB.  Sucks because I need some 125Bs.


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## Chuck D. Bones

I listened to the sound clip a few more times.  Around 11 seconds in, I hear the dry signal clean, the first repeat is clean, and the repeats after that are distorted.  This points to the path thru the REPEATS control.  Pretty sure I know the cause of the distortion.  I have a question into The Man himself.  If I'm right, this is easily fixed and there's nothing wrong with your PT2399.

As a check on my theory, turn REPEATS all the way down and see if you get any distortion.


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## absolvism

Chuck D. Bones said:


> As a check on my theory, turn REPEATS all the way down and see if you get any distortion.



At least with my pedal, there actually is dirt in the first delay (and the sole repeat w REPEATS at 0). If I play very softly, I might not get as much dirt, so that's what you may have been hearing in the other clip.

Here's a clip with REPEATS at 0 with some stronger plucks. https://ellisedwards.com/content/1_repeat.mp3

Thanks for the help, Chuck!


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## Chuck D. Bones

OK, that shoots down that theory.  The PT2399 is still the prime suspect.  

Since I have PT2399s from 2 or 3 different sources, the next time I build a pedal with a PT2399 in it, I'm installing sockets!


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## absolvism

Chuck D. Bones said:


> OK, that shoots down that theory.  The PT2399 is still the prime suspect.
> 
> Since I have PT2399s from 2 or 3 different sources, the next time I build a pedal with a PT2399 in it, I'm installing sockets!


Ok, so I tried 2 other PT2399’s and am still having the issue.

The board was a bit fluxy (I didn’t have flux remover on hand yet when I built this one and IPA was leaving a mess) so I was going to try to clean the board and replace the wiring, BUT I managed to pull off the GND pad from the foot pedal wiring area (see pic). The pad on the other side is intact. Is there a workaround or is the board shot? Can I attach that GND wiring to a different connection? Sorry to add more problems to this troubleshooting ?


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## absolvism

Here’s full pics of both sides of the board minus ICs and ext wiring btw


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## Chuck D. Bones

absolvism said:


> Ok, so I tried 2 other PT2399’s and am still having the issue.
> 
> The board was a bit fluxy (I didn’t have flux remover on hand yet when I built this one and IPA was leaving a mess) so I was going to try to clean the board and replace the wiring, BUT I managed to pull off the GND pad from the foot pedal wiring area (see pic). The pad on the other side is intact. Is there a workaround or is the board shot? Can I attach that GND wiring to a different connection? Sorry to add more problems to this troubleshooting ?


Is the thru plating still in the hole, or did that come out with the wire?  You can either pick up ground from somewhere else, or resolder to the remaining pad.  I'd strain-relieve the wire after soldering with a drop of epoxy so the wire doesn't pull off the remaining pad if stressed.

If IPA is leaving a mess, it's because you're not using enough.  I flood my boards to wash the flux away. 

Those stamped steel sockets are not the best.  Poor retaining force, especially after inserting and removing the ICs a few times.  I checked all the parts on the top half of the board and they look ok.  Pad 3 of the MIX pot looks like the solder may not have wetted to the pad.  Hard to tell due to glare.


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## absolvism

Chuck D. Bones said:


> Is the thru plating still in the hole, or did that come out with the wire?  You can either pick up ground from somewhere else, or resolder to the remaining pad.  I'd strain-relieve the wire after soldering with a drop of epoxy so the wire doesn't pull off the remaining pad if stressed.
> 
> If IPA is leaving a mess, it's because you're not using enough.  I flood my boards to wash the flux away.
> 
> Those stamped steel sockets are not the best.  Poor retaining force, especially after inserting and removing the ICs a few times.  I checked all the parts on the top half of the board and they look ok.  Pad 3 of the MIX pot looks like the solder may not have wetted to the pad.  Hard to tell due to glare.


I appreciate you taking a peek at it.

I feel like it’s just the silver coating on the pad of the one side that came off. I think the inner plating is still there. I’ll try resoldering to it first and epoxy gluing as you recommend.

2 quick followup questions if that’s ok—

At what stage do you flood wash your PCBs? What I’m wondering is: other than pots and ICs, what other components would be too sensitive to be installed prior to IPA flooding the board?

And what  you recommend in place of the stamped steel sockets?


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## Chuck D. Bones

I wash my board before installing the pots to avoid washing flux into the pots.  IPA won't hurt pots, but dirty IPA might.  If I have to do cleaning with pots in place, I direct the flow of dirty IPA away from the pots.  I use a toothbrush to scrub any stubborn spots.  Not aware of any other parts that are sensitive to IPA.

Small Bear, Mouser, DigiKey and others sell machined pin sockets.  They cost a little more, but are much more reliable.  You want to keep dirty IPA out of sockets too.
http://smallbear-electronics.mybigcommerce.com/ic-socket-machine-pin-mill-max-8-pin/


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## absolvism

Ok so I’ve torn this thing apart and banged my head against every wall—
I’ve:
• Reflowed bunk or questionable joints
• Swapped in/out 2 other PT2399 (from Smallbear)
• Replaced every bit of wiring
• Replaced hardware
• Removed fluxy film from rear
• Added footswitch daughter board
• Prayed to every god
.. and this damn thing is still distorting very audibly in the repeat signal

I’ve verified that all the joints look good and appear to make solid connections. I can’t even imagine where to go next but I don’t want to throw this in the garbage 

Any thoughts? Is it possible/realistic the 2 additional PT2399 chips from SB are still bad? That seems like the obvious culprit but I’m 0/3, and 2 bad ones from SB seems hard to believe. 

Could there be a quality issue with parts? Like is anything I’ve got in there not recommended? Could the clip-type sockets be a problem? Are the blue 1u caps crappy? Could either cause dist in the signal?

Other pedals have worked out totally fine but this has me baffled.
@bschobs: Did you ever get yours fixed??


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## Chuck D. Bones

A few shots in the dark:
Verified that the 5V supply on pin 1 of the PT2399 is in spec.
Try subbing a different dual opamp for IC3, something other than an LM833.
If you have an audio probe, try setting REPEATS to zero and listen to pin 15 (input) and pin 12 (output) of the PT2399.  This will confirm whether or not the PT2399 is the source of the distortion.

I wonder where leaving pin 13 on the PT2399 floating could be causing problems.  Princeton is pretty economical with applications information in their datasheet.  They don't say one way or another whether it is ok to float any of the pins.  Generally, it's a bad idea to leave the inputs of an opamp not connected to anything.


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## absolvism

Chuck D. Bones said:


> A few shots in the dark:
> Verified that the 5V supply on pin 1 of the PT2399 is in spec.
> Try subbing a different dual opamp for IC3, something other than an LM833.
> If you have an audio probe, try setting REPEATS to zero and listen to pin 15 (input) and pin 12 (output) of the PT2399.  This will confirm whether or not the PT2399 is the source of the distortion.
> 
> I wonder where leaving pin 13 on the PT2399 floating could be causing problems.  Princeton is pretty economical with applications information in their datasheet.  They don't say one way or another whether it is ok to float any of the pins.  Generally, it's a bad idea to leave the inputs of an opamp not connected to anything.


Thanks for the reply and the ideas to investigate. I’ll probe into these as best I can and report back. I truly appreciate it


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## BurntFingers

Install a 5mm green led between pin 7 and ground. Long leg to pin 7, short to gnd (pin 3 on the 2399).

This distortion in the repeats is well known across many diy forums. Modern thinking also suggests using 1 5v regulator per chip as oppose to both coming off the same 5v line.

You can test the led thing with a crocodile clip. Make a small hook at the end of the long leg, hook it around pin 7, the clip the other leg to ground. No soldering, no mess, but it worked for me on a different pedal using a similar topology.


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## bschobs

No I am waiting on my PT2399s to arrive from SB.


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## absolvism

Hey @Chuck D. Bones - I checked the V to pin 1 on the socket for the PT2399 and it showed 4.81. Is this an ok value? Datasheet implies it can go down to 4.5. Also --- I did one more test before I was going to try @BurntFingers idea with the green LED (which I will still try) and it was interesting.

So I pulled out the 2399 entirely and ran signal through with it engaged, and I found that with the mix on and variable levels of repeat I can get the distortion without the PT2399 in at all, on the initial note hit. It's a little hard to coerce out, but especially played a bit harder on 6th and 5th strings it's definitely distorting in a way it should not.

I have built a probe, but not yet probed. I found it interesting that I could get it to fizz without any PT2399 in. It seems to suggest to me that there's something else in the circuit or build that causing the fizz and maybe the PT2399 is amplifying that signal error? Does this make sense to anyone or point to another suspect component?


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## Chuck D. Bones

I don't think that's a fair test.  With the PT2399 out, IC3 will not bias correctly and the signal can flow backwards thru the Repeat path.  

Not surprisingly, there are some shortcomings to EQD's design.  IC3 is biased by the PT2399.  Not good because the PT2399 runs on +5V and it's output is biased at 1/2 of that. You measured +4.8V on IC2-1, which means that IC2-12 is probably around +2.4V.  IC3 is DC-coupled to IC2, so it's also biased at +2.4V.  That leaves very little headroom.  The Sea Machine, by comparison, biases all of the opamps at +4.5V.  I built a Sea Machine and tweaked the TIME control so I works like the Space Spiral, only without the headroom problem.  

The LED will help the PT2399's headroom problem, but if you're driving this pedal with hot pickups, then there's still the opamp headroom issue to deal with.

This is no fault of PedalPCB.  They faithfully replicate the original pedal, warts and all.  With some of those pedals, it's up to us to improve on the original's design.


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## absolvism

Chuck D. Bones said:


> I don't think that's a fair test.  With the PT2399 out, IC3 will not bias correctly and the signal can flow backwards thru the Repeat path.
> 
> Not surprisingly, there are some shortcomings to EQD's design.  IC3 is biased by the PT2399.  Not good because the PT2399 runs on +5V and it's output is biased at 1/2 of that. You measured +4.8V on IC2-1, which means that IC2-12 is probably around +2.4V.  IC3 is DC-coupled to IC2, so it's also biased at +2.4V.  That leaves very little headroom.  The Sea Machine, by comparison, biases all of the opamps at +4.5V.  I built a Sea Machine and tweaked the TIME control so I works like the Space Spiral, only without the headroom problem.
> 
> The LED will help the PT2399's headroom problem, but if you're driving this pedal with hot pickups, then there's still the opamp headroom issue to deal with.
> 
> This is no fault of PedalPCB.  They faithfully replicate the original pedal, warts and all.  With some of those pedals, it's up to us to improve on the original's design.


Oh for sure I don't think PedalPCB is at any "fault" of any kind. Just the reverse - I think he is a literal hero. And I appreciate everyone's help- I hope to be at a point where I can pay it forward someday. I just keep holding out hope that there is something that can be done that will tame this distortion/improve on this pedal & it can end up useable. (Also, the other PedalPCB boards I've built out have gone together perfectly FWIW - such an awesome company)

I didn't realize that a test without the PT2399 in is not a real or fair test. Disregard entirely.

I measured IC2-1 to IC2-12 and it reads at +2.45V. Am I understanding correctly that the IC3 headroom bias issue is a suspect for the distortion? Is that an unmodifiable scenario? The guitar I was testing w/ was a LP with pretty tame pickups. 

I have some various opamps coming in the mail on a slow boat, so I can can swap IC3 for something else in some time and report back, as well as re: audio probe.

I had also read about someone in a similar topology changing one of the pots from 50k -> 25k, but since it's fizzing even on low times/low repeats/low mix, that doesn't seem like it could help or am I not seeing things right?


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## Chuck D. Bones

It would be good if someone who owns a Space Spiral or Dark Rift could chime in and confirm or refute whether this is normal behavior for that pedal.  

My modified Sea Machine (Sea Horse) makes a little noise and distortion at longer delays, but that's the consequence of slow sampling.  The PT2399 was designed for reverb applications.  Longer delays will not sound as clean.  We could tune the anti-aliasing filters down lower, but then the tone would be darker.  It's a compromise.  

If you want a clean, crystal clear delay, then FV-1 is the way to go.


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## Nostradoomus

I only noticed a bit of degradation at longer delay times, as is normal with PT2399s...


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## absolvism

There's no way this is normal behavior- I listened to SS demos and it has nothing to do with the longer delay, which would is understandable. 

Here's a video showing the problem. I am playing fairly hard in order to accentuate the problem, but there is no setting where this is not sound-ruining. You'll be able to see clearly what I mean:  




			http://www.ellisedwards.com/content/darkrift3.mov
		


I also still think the highest probability is that I've done something stupid or rookie (or 3 bad PT2399s), and it doesn't have anything to do with the circuit or the nature or standard noise of PT2399. I've read heaps of posts about PT2399's in the last week and it seems like this is a complaint that does arise, so I'm hoping working through this might save other PedalPCB customers some annoyance down the line, and saves me (and maybe some others) from having to take a total L on this. If that happens, I'll ring up the FV-1. Sorry this is dragging on.


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## absolvism

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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## Nostradoomus

Did you try swapping the LM833? I think I used a TL062 in mine as it sounded a bit cleaner.


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## BurntFingers

I still think the green led is worth investigating. It doesn't sound like that's been tried.


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## absolvism

BurntFingers said:


> I still think the green led is worth investigating. It doesn't sound like that's been tried.


Hey @BurntFingers I just did it, and wow- the distortion is DEFINITELY notably gone or at least reduced to a point where the pedal is certainly usable for the first time and within some normal range of expectation. I can see the led clipping and the output isn't crunching with every single note. It might not be the most ideal or final solution, but I can actually play on this thing now. I've only played around to test for a min before doing a more legit wiring, but it actually finally sounds pretty good!

I'm going to still investigate swapping the LM833 for a TL062 or TL072 (I only have a 072 on hand) and probing around a bit but wow, just from playing for a sec with it with the LED hack in place, this pedal feels like it's on the road to redemption.

EDIT: The fizzing is still there, especially on higher mix value, but it's reduced by about 80% and if it doesn't get better from here, it's still at least playable


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## BurntFingers

Awesome. That's a win.


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## moonlightpedalbuilds

Dark rift


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## wrentema

BurntFingers said:


> Install a 5mm green led between pin 7 and ground. Long leg to pin 7, short to gnd (pin 3 on the 2399).
> 
> This distortion in the repeats is well known across many diy forums. Modern thinking also suggests using 1 5v regulator per chip as oppose to both coming off the same 5v line.
> 
> You can test the led thing with a crocodile clip. Make a small hook at the end of the long leg, hook it around pin 7, the clip the other leg to ground. No soldering, no mess, but it worked for me on a different pedal using a similar topology.


I had the exact same problem and this indeed helped a lot. (Although I didn’t hear a difference with red and yellow leds.)
Can you explain why this works? Just curious.


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## BurntFingers

wrentema said:


> I had the exact same problem and this indeed helped a lot. (Although I didn’t hear a difference with red and yellow leds.)
> Can you explain why this works? Just curious.



In basic terms, the first repeat is boosted causing the chip to distort. The green led clips this signal and stops it distorting by providing a ceiling of sorts.


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## bschobs

I would add though that this Dark Rift is noisier than most.  I've built two PT2399 delay circuits since this one and the noise isn't really an issue with them (and yeah I tried swapping out different PT2399's from different sources)


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## Danbieranowski

BurntFingers said:


> In basic terms, the first repeat is boosted causing the chip to distort. The green led clips this signal and stops it distorting by providing a ceiling of sorts.


Brilliant.


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## Chuck D. Bones

One reason the Space Spiral (Dark Rift) is noisy is because EQD screwed-up the filtering going into and out of the PT2399.  They did a better job on the Sea Machine.


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## BurntFingers

Chuck D. Bones said:


> One reason the Space Spiral (Dark Rift) is noisy is because EQD screwed-up the filtering going into and out of the PT2399.  They did a better job on the Sea Machine.



I bet they can't wait for the boneyard version.


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## Chuck D. Bones

Ha ha ha ha ha.  I published a build report on my modded Sea Horse, but did not disclose the details of all the mods.  I'm happy to do so if there is interest.  The Sea Horse and Dark Rift are basically the same pedal, the main difference is the DR can produce longer delays.  One of the mods I performed on the SH was to increase the range of the TIME control.  Other mods were fixing the LFO tick, changing the LFO speed range and retuning the anti-aliasing filters.  The filters can be fixed in the DR, but it takes more effort to undo the screw-ups on that board.


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## Hoenig

Just checking to see how this was going? I built a vero deep blue delay and ran into this problem. I socketed all the caps at the IC and spent a week trying different sizes until I found the least shitty sounding combo. Still breaks up but is usable in some settings. Never knew about the green led though!


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## seers

Chuck D. Bones said:


> I listened to the sound clip a few more times.  Around 11 seconds in, I hear the dry signal clean, the first repeat is clean, and the repeats after that are distorted.  This points to the path thru the REPEATS control.  Pretty sure I know the cause of the distortion.  I have a question into The Man himself.  If I'm right, this is easily fixed and there's nothing wrong with your PT2399.
> 
> As a check on my theory, turn REPEATS all the way down and see if you get any distortion.


I am having this exact issue, and when i turn my repeats down the signal cleans up beautifully. Could you shed some light on your theory? it may solve my problem, many thanks


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## Chuck D. Bones

Try turning D2 around.


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## seers

Chuck D. Bones said:


> Try turning D2 around.


ive got a pcb where theyre both going the same way, i reversed d2 already


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## Dan0h

BurntFingers said:


> Install a 5mm green led between pin 7 and ground. Long leg to pin 7, short to gnd (pin 3 on the 2399).
> 
> This distortion in the repeats is well known across many diy forums. Modern thinking also suggests using 1 5v regulator per chip as oppose to both coming off the same 5v line.
> 
> You can test the led thing with a crocodile clip. Make a small hook at the end of the long leg, hook it around pin 7, the clip the other leg to ground. No soldering, no mess, but it worked for me on a different pedal using a similar topology.


I will be trying this mod this weekend. I have two other PT chip delays and this is the only one that has excess noise in the repeats. At first I thought it was an artifact of the Lo-fi ness, but if the led mod cleans it up I’ll be stoked.


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## manfesto

Dan0h said:


> I will be trying this mod this weekend. I have two other PT chip delays and this is the only one that has excess noise in the repeats. At first I thought it was an artifact of the Lo-fi ness, but if the led mod cleans it up I’ll be stoked.


It does the trick (at the slight expense of maximum mix volume; it’s not bad but it’s noticeable), and if you’re lazy like me you can actually just solder the LED straight to the PT2399 and not have to disassemble the whole thing lol


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## Bobbyd67

Nice ! That this got resolved  I am in the process of building 2 of these if I get that issue at least I'll know what to do


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## Dan0h

I could not wait till the weekend… and can confirm it does the job of removing the hiss/distortion on the repeats by >90%. It seems to have cut a tiny bit of high end out, almost unnoticeable and can no longer push it into deep self oscillation without very gnarly distortion occurring but I can get right up to the edge of oscillation and it’s pretty pristine. Kudos to who ever figured this out. Makes no sense to me but it works so there it is.


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