# Dark Rift Delay



## digitalsea

Hi all,

Tearing my hair out with this one.

I’m only getting clean signal when engaged. I’ve switched out all the ICs and checked over too many times.

Is there anything that you guys can see that I’m missing?

Thanks for looking.


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## Mcknib

Nothing stands out can't fully see R11, 16, 20, 31 and 32 and obviously can't see capacitor values 

The only other thing I notice is that D2 and 3 orientation differs from your silkscreen to the pcb image those I think just limit / clamp feedback 

What's your PT2399 voltages


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## Barry

What's that sticking up amid the Pots on the left?


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## Chas Grant

I believe Mcknib nailed it on D2 and D3! Remove both and try the circuit without the diodes, if you have a wet signal without the diodes in the circuit, then replace them in the opposite direction of the silk screen. On the schematic the anode of the diodes is connected to ground, the way the PCB looks, the cathode is connected to ground. You can see this in your picture by looking at the cathode of D2 and R5 which is just to the left of D2. They both have the 4 points connected to the ground plane of the PCB. If the diode is reversed you will short your wet signal to ground.


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## Barry

I built one recently and had no issue orienting the diodes per the silkscreen


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## Mcknib

Chas Grant said:


> If the diode is reversed you will short your wet signal to ground.


I thought that may well be the case signal getting dumped to ground but also thought it might be a layout update

Maybe @PedalPCB could let us know if it's a layout thang

You can simply continuity check D2 and 3 cathodes connect to C7 and repeats lug 2 as they should or even easier as @Chas Grant says check both anodes go to ground


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## Robert

There was a batch of boards where D2 was reversed but it didn't cause any issues.  

These are just to limit the feedback loop, it's a typical diode-to-ground hard clipping arrangement.


This is the correct orientation, but even if one (or both) were installed incorrectly it wouldn't cause a "no signal" condition.





More importantly, your board is not one of these.   Yours is the current revision so you should follow the silkscreen on the board.


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## Mcknib

You're better posting all IC voltages it may highlight the problem area


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## digitalsea

Thanks all. Apologies for the delay in replying, had work. Appreciate the responses.

I’ve clipped D2 and D3 to remove them from the circuit and can confirm that @PedalPCB is correct and isn’t the issue here.

I’m going to learn how to use a multimeter and report back. Might take me a hot minute.
It’s weird. I’ve built a good dozen or so from pedalpcb and never had anything like it.

‘Thanks again


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## digitalsea

Barry said:


> What's that sticking up amid the Pots on the left?


That’s a green led that was connected to pin 7 in order to solve the noise issue. There is a good thread where a user solved the noise issue by connecting these up. I thought that was the problem initially, so I clipped the connection to pin 7, but have left the led connected to ground in the interim. The led legs are not touching any pads or the like, so shouldn’t be causing an issue. Unless someone points out it’s a problem? No issue to remove it


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## digitalsea

It wouldn’t be an issue with the chip specs I’ve used? I note that I’ve used an lm324N and a 833N. Whereas the build docs call for lm324A?

I did a quick google prior to using them and didn’t see anything that I thought would be a problem, but I’m happy to be wrong


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## Mcknib

Most of the lettering after IC part numbers is manufacturer code usually for package type like N you'll also see stuff like UB for unbuffered B buffered L leaded and so on, some datasheets list package types etc

So it doesn't make a difference in your case as you say


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## r.nandez54

I'm running into this same issue, did you figure out what the problem was?


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## r.nandez54

I'm also having this issue. When the pedal is on there is a boost in volume and I attempted to pull out pt2399 to see if there were any changes with anything and no change was noticed. My voltages across pt2399 are:
1, 4.99
2, 2.503 
3, .1 
4, .1 
5, 2.801 but keeps dropping
6, 2.504 
7,.785 
8, .801 
9, 2.501 
10, 2.545 
11, 46.2 
12, 1.062 
13, 2.520 
14, 2.504 
15, 2.502 
16, 2.525


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## Chas Grant

Pin 5 is an AC square wave. Check it with DMM on AC and see what it is. Recheck pin 11, 46.2 is a wee bit high. Pins 11 and 12 are the voltages that are off.


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## r.nandez54

Chas Grant said:


> Pin 5 is an AC square wave. Check it with DMM on AC and see what it is. Recheck pin 11, 46.2 is a wee bit high. Pins 11 and 12 are the voltages that are off.


Ac on the DMM is the v~?
If I did that correctly it fluctuates around 5.99. Also, I made a mistake with the pinouts 9 is 16 and 16 is 9. Here is the readings I'm getting at the moment with correct pin out 
1, 4.99
2, 2.504
3, 0.1
4, 0.1
5, 5.99 and bounces around but settles on 000
6, 2.504
7, .823
8, .835
9, 2.538
10, 2.505
11, 2.505
12, 2.540
13, 3.4
14, sometimes its 46.0 sometimes its 4.992
15, 2.577
16, 2.504


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## digitalsea

r.nandez54 said:


> I'm running into this same issue, did you figure out what the problem was?


Not that this is in anyway helpful, but no, I haven't managed to fix it. 

I've put it on the shelf and moved onto other projects to build back some enthusiasm in tackling it


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## r.nandez54

digitalsea said:


> Not that this is in anyway helpful, but no, I haven't managed to fix it.
> 
> I've put it on the shelf and moved onto other projects to build back some enthusiasm in tackling it


No worries man. I'll update if I can figure anything out, maybe we have the same issue.


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## Chas Grant

OK, These readings look correct. Pin 5 is not used in this circuit and it should fluctuate between 0 and roughly 5V. Pins 13 and 14 are not used either, that's why those are a bit strange. Everything else looks good. Pin 1 is Power in, +5V. Pin2 is internal voltage, the PT2399 cuts the +5 in half and runs on 2.5V. Pins 3&4 are grounds. Pin 5 not used. Pin 6 is the oscillator input from the LFO, its always 2.5V. Pins 7&8 are grounded through the 100n caps, so a low voltage is good. Pins 9 through 12, 15 and 16 are inputs and outputs to your circuits and the bias voltages are correct. The PT2300 seems to be working. Check Voltages on IC1, IC3 and IC5.  IC1 and IC5 are referenced to 4.5V, So that voltage should be a common value on them, With exception to Vcc and GND. IC3 is referenced to ground, so besides Vcc and GND, your readings may be at or near zero. Post the readings when you get them.


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## r.nandez54

Chas Grant said:


> OK, These readings look correct. Pin 5 is not used in this circuit and it should fluctuate between 0 and roughly 5V. Pins 13 and 14 are not used either, that's why those are a bit strange. Everything else looks good. Pin 1 is Power in, +5V. Pin2 is internal voltage, the PT2399 cuts the +5 in half and runs on 2.5V. Pins 3&4 are grounds. Pin 5 not used. Pin 6 is the oscillator input from the LFO, its always 2.5V. Pins 7&8 are grounded through the 100n caps, so a low voltage is good. Pins 9 through 12, 15 and 16 are inputs and outputs to your circuits and the bias voltages are correct. The PT2300 seems to be working. Check Voltages on IC1, IC3 and IC5.  IC1 and IC5 are referenced to 4.5V, So that voltage should be a common value on them, With exception to Vcc and GND. IC3 is referenced to ground, so besides Vcc and GND, your readings may be at or near zero. Post the readings when you get them.


Appreciate the help dude. 
Tl072 reads:
1, 2.944
2, 2.940
3, 2.778
4, 0.1
5, 3.272
6, 3.290
7, 3.273
8, 8.83

LM833N:
1, 2.773
2, 2.763
3, 2.576
4, 0.0
5, 2.582
6, 2.587
7, 2.588
8, 0.80

LM324N:
1, 4.627 jumps +/-.002
2, 4.410
3, 4.401
4, 8.82
5, 4.537 jumps +/-.002
6, 4.361
7, 4.407 
8, 3.821 jumps +/-.005
9, 3.835 jumps +/-.005
10, 3.835 jumps +/-.005
11, .1
12, 4.399
13, 4.557 jumps +/-.005
14, 3.839 jumps +/-.005

Let me know if you need anything else. 

I was wondering if I might have a bad transistor, 78L05. I was reading that those could just be bad, what I read had no relation to this pedal but I'm reaching for any possibility at this point. No clue if this is how I'm supposed to read that transistor but reading it on the silkscreen left to right it is 4.99, 0.0, 8.82. Hope any of this might help you help me lol.


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## digitalsea

Hi all,

Tearing my hair out with this one.

I’m only getting clean signal when engaged. I’ve switched out all the ICs and checked over too many times.

Is there anything that you guys can see that I’m missing?

Thanks for looking.


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## Chas Grant

The 78L05 isn't a transistor, but a voltage regulator, and you have already checked it. The PT2399 needs +5V power to operate. This is pin 1  which is 4.99V. It gets the 5V from the 78L05, so since pin 1 of the PT2399 is 4.99V the 78L05 is good.

The LM833 actually has an input coming from the PT2399 into pin . The output from the 2399 is 2.5 volts and that's what you have on the I\O pins of the 833, so its good. (I missed the 2.5 input from the 2399, that's why I thought it may have a low voltage)

The Tl072 has low Vref on pins 3 and 5.Need to see if this is normal or an issue. Try resoldering the the pins on this op amp, if you dtill have low Vref after, the try removing TL072and re-measure voltages'

Also the LM324 has a low voltage on pins 12, 13, and 14. Pin 12 is referenced straight to pin 12, it should read 4.5V. If you can resolder pins 12, 13 sns 14,  then recheck their voltages


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## r.nandez54

Chas Grant said:


> The 78L05 isn't a transistor, but a voltage regulator, and you have already checked it. The PT2399 needs +5V power to operate. This is pin 1  which is 4.99V. It gets the 5V from the 78L05, so since pin 1 of the PT2399 is 4.99V the 78L05 is good.
> 
> The LM833 actually has an input coming from the PT2399 into pin . The output from the 2399 is 2.5 volts and that's what you have on the I\O pins of the 833, so its good. (I missed the 2.5 input from the 2399, that's why I thought it may have a low voltage)
> 
> The Tl072 has low Vref on pins 3 and 5.Need to see if this is normal or an issue. Try resoldering the the pins on this op amp, if you dtill have low Vref after, the try removing TL072and re-measure voltages'
> 
> Also the LM324 has a low voltage on pins 12, 13, and 14. Pin 12 is referenced straight to pin 12, it should read 4.5V. If you can resolder pins 12, 13 sns 14,  then recheck their voltages


Thanks for correcting me re/78L05

I got the same values after trying to resolder. I should mention that mine are socketed as well. I'm not sure if this is supposed to happen but if I take out Tl072 and test the socket itself I get a different reading 2.950 vs 2.778 with IC pin 3 and 4.342 vs 3.290 with the IC pin5.
On LM324 there is no change at all.


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## Chas Grant

The 2.9 to 2.7 on pin 5 is not a biggie, but pin 3 going to 3.2 is weird. Try swapping the TL072. If you don't have another TL072, any dual op amp with the same pin out should work.


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## r.nandez54

Chas Grant said:


> The 2.9 to 2.7 on pin 5 is not a biggie, but pin 3 going to 3.2 is weird. Try swapping the TL072. If you don't have another TL072, any dual op amp with the same pin out should work.


I have a few so I tried 3 different TL072's last night as well as 3 different LM324. Should've mentioned that too, sorry.


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## Chas Grant

Actually lets back up a second. With the TL072 removed you have 2.95 volts on pin 3. It should be 4.3 like pin 5. With the IC removed, measure voltage from both sides of R3, its the 1Meg resistor below the TL072. It should be ~4.5V on both sides if TL02 is removed


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## r.nandez54

For R3 this is what I'm getting with TL072 removed
Negative probe to the left reads: -1.064
Positive probe to the left reads: 1.067


Chas Grant said:


> Actually lets back up a second. With the TL072 removed you have 2.95 volts on pin 3. It should be 4.3 like pin 5. With the IC removed, measure voltage from both sides of R3, its the 1Meg resistor below the TL072. It should be ~4.5V on both sides if TL02 is removed


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## Chas Grant

Somethings not right, R4 and R3 are the 2 resistors below the TL072, with the chip removed you should have about 4.5 V on both sides of both resistors. Check the build doc to make sure your on the right resistors and double check voltage on them if you can. Make sure the black lead is to a good ground and check the voltage with red lead.


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## r.nandez54

Chas Grant said:


> Somethings not right, R4 and R3 are the 2 resistors below the TL072, with the chip removed you should have about 4.5 V on both sides of both resistors. Check the build doc to make sure your on the right resistors and double check voltage on them if you can. Make sure the black lead is to a good ground and check the voltage with red lead.


Ok, so this morning I was just going positive and negative leads on the resistor. Now I'm putting the negative lead on the main negative point from the power jack. I confirmed that R4 is correctly a 47k resistor and is directly below TL072 and R3 is correctly a 1M resistor and is directly below R4. Here are my readings:
Left side of R3 is 4.357
Right side of R3 is 2.986 
Left side of R4 is 4.358
Right side of R4 4.330


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## Chas Grant

It looks like the right side of R3 has a partial path to ground. It could be C2 is leaking or you have a small bridge somewhere. Check DC voltage on both sides of R2. It should be zero.


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## r.nandez54

Chas Grant said:


> It looks like the right side of R3 has a partial path to ground. It could be C2 is leaking or you have a small bridge somewhere. Check DC voltage on both sides of R2. It should be zero.


Left side of R2 is 1.053
Right side of R2 is 1.054


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## Chas Grant

C2 is leaking, there shouldn't be DC there. Try replacing it. Not sure if this was the main issue, I think it would affect tone more, but with electronics you never know, especially when the component is deteriorated. (Got my but kicked by a deteriorated transistor for over a month one time  )


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## r.nandez54

Chas Grant said:


> C2 is leaking, there shouldn't be DC there. Try replacing it. Not sure if this was the main issue, I think it would affect tone more, but with electronics you never know, especially when the component is deteriorated. (Got my but kicked by a deteriorated transistor for over a month one time  )


I'll do this when I get home, I think this might be the problem. Question about those 1uf caps I'm using, the ones I got were polar I think. One leg is longer and the have a little plus sign on that side. https://www.taydaelectronics.com/1uf-16v-radial-tantalum-capacitor.html are those ok to use in this case?


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## Chas Grant

They will work, but not ideal. Thy have to go in a certain way. You have to look at schematic and figure out which side has the higher voltage, then the + side goes that way. You may be able to measure voltage to ground on each leg of the cap then see if the + side is on that side. It can be tricky sometimes. You could replace also them with 1uF MLCC caps, they can go either way and they are smaller than 1uF box film caps, so they will fit with no problems.


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## Chas Grant

Thinking about it, if you used all tantalum caps for the 1uF's, this very well could be the issue. They are in the signal path in quite a few places, if they are in the wrong way they will block the signal.


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## r.nandez54

Chas Grant said:


> Thinking about it, if you used all tantalum caps for the 1uF's, this very well could be the issue. They are in the signal path in quite a few places, if they are in the wrong way they will block the signal.


Once you mentioned that they do have to go a certain way I'm almost sure of it. And it looks like @digitalsea might be using the same caps I am. I tip my hat to you sir, thank you. I'll report back after getting this corrected.

Side question, how did you learn all these specifics? Is it your job or just long time hobby?


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## Chas Grant

I was an electronics technician in the US Navy. After getting out I stayed in the field and saw it change from through hole to SMD components( I hate SMD BTW). The equipment I worked on had nothing to do with audio, so the audio side is recent. But electronics are electronics. How I got into pedals, a while ago my daughter wanted to learn to play, so she hi-jacked my Fender Tele and started learning ( I had to buy her a Strat to get my Tele back ) . When she started to ask about pedals and I saw the price on some of them I decided to build them. There was a learning curve but not to bad, and still a lot I don't know. This here forum has helped me a lot, and helping out here makes me learn even more. I have learned that the pedal "Rabbit Hole" is very deep, I haven't got to the bottom yet! But it allows me to work with through hole components again and my soldering is back up to snuff, so all is good!


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## r.nandez54

Chas Grant said:


> I was an electronics technician in the US Navy. After getting out I stayed in the field and saw it change from through hole to SMD components( I hate SMD BTW). The equipment I worked on had nothing to do with audio, so the audio side is recent. But electronics are electronics. How I got into pedals, a while ago my daughter wanted to learn to play, so she hi-jacked my Fender Tele and started learning ( I had to buy her a Strat to get my Tele back ) . When she started to ask about pedals and I saw the price on some of them I decided to build them. There was a learning curve but not to bad, and still a lot I don't know. This here forum has helped me a lot, and helping out here makes me learn even more. I have learned that the pedal "Rabbit Hole" is very deep, I haven't got to the bottom yet! But it allows me to work with through hole components again and my soldering is back up to snuff, so all is good!


My man! That's some serious experience you got there. That's cool that your daughter got into something you both could share experiences in as well, I have a newborn and look forward to things like that. 

I really appreciate the help. Like I mentioned before I'll report back after I figure out either the orientation on the tantalum caps or just buying some MLCC's.  Thanks again!


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## Chas Grant

An easy way to figure the caps, but not always 100%, is to de-solder the cap, power up the circuit and measure voltage across the pads of the missing cap. One way the it will be positive and the other negative. When its positive, where the red lead is, that should be the + lead of the cap.


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## r.nandez54

Chas Grant said:


> An easy way to figure the caps, but not always 100%, is to de-solder the cap, power up the circuit and measure voltage across the pads of the missing cap. One way the it will be positive and the other negative. When its positive, where the red lead is, that should be the + lead of the cap.


So I gave it a go and I'm still not getting any effect sound. I'm using a sound probe to see if I can follow the sound but I'm still learning how to use it. I'm gunna wait till after the new year to order from tayda for those MLCCs.


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## Chas Grant

Understandable. Trying to sub polarity sensitive caps for non-polarity caps can be tricky. One or two, easy but there's a bunch of 1uF caps in this circuit. Another thing, if your mail is anything like mine, if you order today, and also order after Jan 1st, they would arrive at same time!, so waiting is the smart move!   Keep the forum updated to how it goes once you get the caps.


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## digitalsea

Hi all,

Tearing my hair out with this one.

I’m only getting clean signal when engaged. I’ve switched out all the ICs and checked over too many times.

Is there anything that you guys can see that I’m missing?

Thanks for looking.


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## Gernot

Did you ever manage to get it going? I am having a very similar experience!


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## r.nandez54

Gernot said:


> Did you ever manage to get it going? I am having a very similar experience!


Not yet. I got another board to see if I did something wrong but still have yet to make a tayda order for all the necessary parts and currently in limbo.


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## Hotcakes

Similar issue when engaged LED on no wet signal but its still clean. I have slightly different parts.


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## Chuck D. Bones

Let's see the other side.  Have you thoroughly inspected all of the solder joints and component values?

I see you melted C8, that would be enough to kill the wet signal.  Replace C8 and any other damaged parts.  Those oversized 1uF caps made it hard to assemble, hmmmmm?


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## Hotcakes

Looking for any bridge connections and wiring mishaps is all I could do until now, I couldn't find any as ugly as it is. The handed down soldering iron I was using had a flat tip as it was so old. Just picked up a new soldering iron and multimeter. Need to read up on how to use a multimeter tonight, not sure what values are good or bad yet.





Chuck D. Bones said:


> Those oversized 1uF caps made it hard to assemble, hmmmmm?


🤣I had no idea they would be so big


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## Chuck D. Bones

All of those solder joints need to be retouched.  Some look cold, most have too much solder on them.  Bend the pots up (gently) so you can work underneath them.  No point in making measurements until the board passes visual inspection.


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## Zamboni

that middle a100k pot above the pcb, does it have a dust cover like the others? I can seen them on the other five, might just be the angle though. If not it could be shorting out.


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## Hotcakes

Chuck D. Bones said:


> All of those solder joints need to be retouched.  Some look cold, most have too much solder on them.  Bend the pots up (gently) so you can work underneath them.  No point in making measurements until the board passes visual inspection.


I took the potentiometers off and retouch everything with my new iron. I was able to remove a lot of solder as well as get better connections. I had the faint workings of each potentiometer under neath a clean guitar but after unplugging and reconnecting everything it was gone. I am guessing that means I need to go everything connection again.


Zamboni said:


> that middle a100k pot above the pcb, does it have a dust cover like the others? I can seen them on the other five, might just be the angle though. If not it could be shorting out.


a100k does not have a cover and was not the cause of the short


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## Pauleo1214

i just built one as well and have the same issue. I have a strong dry signal when the effect is engaged but no wet signal either.


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## ADAOCE

No sockets on the ICs either. Maybe you put too much heat on the chip legs?


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## Pauleo1214

I can't speak for HotCakes but my ICs are socketed. I know R. Nandez socketed his ICs as well. I am having the same issue.


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## Hoenig

I've put together a couple of these and made the same mistake both times. C8 is 1n not 1u, the wrong value here will lead to almost completely dry signal. Met someone one a facebook forum that made the same mistake, easy to miss


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## Robusto

Hoenig said:


> I've put together a couple of these and made the same mistake both times. C8 is 1n not 1u, the wrong value here will lead to almost completely dry signal. Met someone one a facebook forum that made the same mistake, easy to miss


Oh, FFS, yep. Came here looking for IC voltages and I did the same thing with C8. With those other 3 1u there, it’s like when you read a sentence that’s missing a word and your brain just fills it in.
Also, Hotcakes, I sympathize, I have those same grey 1u giants and it was tough to source any smaller ones. Finally uncovered them in the pile at Mouser and they had a grand total of 17 in stock and they took two weeks to get here. Things are rough down in Texas.


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## Dan0h

JFC. I just did the same god damn thing. 1u in C8 instead of 1n. And oddly enough I think my D2 is backwards compared to the print out PDF but if that doesn’t matter I’m not going to pull that out. Will be swapping C8 out tomorrow. 
Clean while bypass and clean engaged with just a faint single repeat when fully blast all knobs. Hoping it’s just the C8. My first issue in a long time.


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## Dan0h

Awesome. That 1u was the problem. This thing rules! Thanks again to the epic help in the threads.


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