I'm starting to build the Dig Dug and I'm just starting this thread as a general Q & A spot for me, as I know I will have difficulty with this.
My first query: Do the 8 LEDs in a row have to be wired up in order for the circuit to work?
Judging by the schem it appears like you'd have a bunch of opens if you didn't include the LED's. They aren't set up like a normal bypass indicator wired straight to ground.
Yeah, it will work, but you need to short the pads together in order to continue with the circuit. If you leave them out, it will create open circuits like Magic said, and your pots will not work.
-Kaleb
mkay so I popped the LEDs in this morning. Still have no wah. I have bypass alright, but when I touch my audio probe to 6 out of the 8 LEDs all I get is this loud square wave sputtering. The other two have no sound when probed. Any ideas?
I'll post IC readings soonish
For IC1 (TL072P) I used TL072PC
For IC2 (CD4017) I used CD4017BE
For IC3 (CD4093BE) I used CD4093BCN
IC1: TL072PCP
P1 2.85
P2 4.74
P3 4.23
P4 0.00
P5 4.74
P6 4.77
P7 4.85
P8 9.52
IC2: CD4017BE
P1 0.00
P2 ~2.40 (this one jumped around a lot from 2.32-2.40)
P3 ~2.40 (this one jumped around a lot from 2.35-2.40)
P4 ~2.40 (this one jumped around a lot from 2.36-2.40)
P5 0.00
P6 0.00
P7 ~2.40 (this one jumped around a lot from 2.34-2.40)
P8 0.00
P9 0.00
P10 0.00
P11 0.00
P12 9.52
P13 0.00
P14 1.92
P15 0.00
P16 9.52
IC3: CD4093BCN
P1 7.60
P2 7.60
P3 1.92
P4 7.60
P5 8.66
P6 2.85
P7 0.00
P8 ~9.52 (this one jumped around a lot from 0.03-9.52)
P9 ~9.52 (this one jumped around a lot from 0.13-9.52)
P10 ~9.10 (this one jumped around a lot from 0.02-9.10)
P11 ~9.52 (this one jumped around a lot from 0.04-9.52)
P12 0.87
P13 0.87
P14 9.52
For those who are visually inclined:
(http://hphotos-iad1.fbcdn.net/hphotos-ash4/s720x720/299436_2064032481768_1273410121_31756411_1396933403_n.jpg)
(http://a1.sphotos.ak.fbcdn.net/hphotos-ak-ash4/s720x720/319595_2064029681698_1273410121_31756409_1207063297_n.jpg)
(http://a4.sphotos.ak.fbcdn.net/hphotos-ak-ash4/s720x720/315998_2064022041507_1273410121_31756405_1408883269_n.jpg)
(http://a6.sphotos.ak.fbcdn.net/hphotos-ak-ash4/s720x720/308990_2064015401341_1273410121_31756404_1331217819_n.jpg)
(http://a7.sphotos.ak.fbcdn.net/hphotos-ak-ash4/s720x720/294094_2064013401291_1273410121_31756403_1151634152_n.jpg)
I reflowed some of the solder on the two LEDs that didn't the came up dead with the audio probe. Now there's no square waveyness on the LED's and sound comes through them. I still can't figure out why I don't have any wah. Do the IC values look alright?
I've seen a couple instances of people having to reverse the LEDs on their board. Should I give this a try? Earlier today, I took out my multimeter, set it to diode, and tested the LEDs to make sure they work. Unexpectedly, when I illuminated one LED, another LED would light up and blink in sequence with the other (like it would in normal operation)
There should be no audio signal coming through the LED's whatsoever ???. This circuit is divided into two sections which are separated and connected by an optoisolator (your vactrol). They are; the filter and the sequencer. The first behavior you described sounds normal to me, if you attach an audio probe to the LED's you should hear a clicking that changes when you increase the speed knob. It is only going through six because your 4-8-6 switch (or something else) is telling the CD4017 to reset on the sixth step. If the 4-8-6 switch is acting weird check the polarity of the reverse voltage diodes D1, D2 and D4. Also for this test I would temporarily remove the random section (pull the bs170 Q2).
Are the LED's working normally? if not you have a problem with the sequencer circuit and I would troubleshoot that first. The first thing I would do is pull the Vactrol out and put a normal LED in its place just so you can monitor how that is working. Once that LED lights up in time with the sequencer your mission is accomplished. Yes I would also try and reverse one of the sequencer LED's as well, if you cannot get the LED's to light then there is either a problem with your counter or the LFO is not working properly.
If the LED's are lighting normally and you still get no wah then you should move onto the filter part of the circuit. First do the LED in place of the vactrol to make sure it is working properly. If it is then I would plug a variable resistor into your vactrol slot and start troubleshooting with that.
Let us know where you get in these steps and we'll try and track the issue down!
Thanks dude! I'm going to pick up a few parts from my local electronics shop later today and then I'll be busy trying these things out. Great ideas!!!
I have sound through the filter section but everything in the sequencing section just has a really loud pulse kinda like a metronome. Is that normal?
Woah. Just reversed the LED for pot 1. Now the thing works but only for stage 1 of the sequencer. But when stage 1 happens all the LEDs light up instead of just pot 1's LED. I'm going to give reversing the rest of the LEDs a try in a bit.
Good news everyone! It kinda works.... All the LEDs are lighting up in cue, as they should. However, there's a loud ticking when I turn up the tone control. It sounds almost like one of those Newton's cradles. You know with the six or so balls that tick back and forth.
Anyway I don't get it. There's also some background ticking and popping that seems to be going in sync with the sequencer
Based on your second comment I have a strong feeling your LED's are backwards. Did you reverse all of them or just one? When you reverse one the others still aren't facing the right way so they wont block the current now traveling in that node. This causes them to all light up. They don't all light up when they are all facing the right way because the LED is a diode and wont allow current to pass provided it is faced correctly. Unfortunately this also means that only one of your sequence steps will work because now the backwards LED's are blocking the 5 volts dc coming out of the other 7 counter pins.
If this jives with what you are seeing reverse the rest of the LED's and report back.
As for the noise that is a really common issue with counter based circuits. I have a goatkeeper clone that I still cant seem to keep quiet. If it is too loud though that is indicative of something wrong. Clicking in the audio path means that the isolation between the digital (sequencer) and the analog portion is not good enough. If you can get a hold of a little inductor I would try and put that between the analog and digital grounds.
Yeah I already flipped around all my LEDs to get then to light up in sequence instead of all at once. My main problem stems from all this background noise but I guess I can live with that. One last thing, though- my pot 8 doesn't seem to be doing anything. I can't seem to control the last step in the 8 sequence at all. It's just always on. Should I audio probe it?
Here's a quick vid I did to capture that clicking sound. This is with the filter control turned all the way up:
http://www.facebook.com/v/2075833096776
and don't worry, that wasn't me playing. It was my girlfriend :P
Damn all those lights are cool looking! I really want to make one of these now ;D
That clicking is a little too much to be poor isolation noise. That fishy pot 8 behavior is suspicious and could be the source of the issue, it sounds like you are only getting a click one time through the whole sequencer cycle too which would make sense if something was wrong with just one step. The LED for step 8 looks to be working though which means that the filter should be responding as well. My money is on a short on pot 8 somewhere, this could be causing a large current spike when the 8th step in the sequence triggers and the excess current draw from the digital side causes a pop in the analog circuit. When you set the 4-8-6 switch for just 4 or 6 steps do you still get a pop?
Off the top of my head, I think that I still get a pop on the last beat of the sequence, no matter which setting it's on (4, 6, or 8).
You don't suppose that I might be getting this because I used high brightness LEDs?
Ughhhhhh. so, whenever there is a pot in the sequence that is turned up all the way, or just about all the way, next to one that is lower in volume, it causes a "pop" in the sound. I have no idea why.
I reflowed the solder on pot 8 to see if I could get it to work and no luck. It still does nothing as far as controlling the volume for that part of the sequence.
:( :( :( :(
Hmm that is weird about pot 8. Maybe the pot is bad? If you have a spare CD4017 pop that in and see if that helps. Temporarily disconnect LED 8 and see if that helps the pop. Also check that D1 D2 and D4 are facing the right directions and that all the 47K resistors on the pot connections are the right values (i've put in 4.7K sometimes and didn't find it till months later ::)).
You could also try putting a capacitor across the LED part of the vactrol. Unfortunately at high speeds you wouldnt likely get any wah change because the cap discharge will be slow. This will just smooth out the transitions in the steps hopefully making that steep square edge a ramp (well actually an exponential decay function). I would try and get the step 8 to work before trying this one as it will reduce the quality of the wah effect.
I've got some parts coming from Mouser, including a new 100kB Alpha pot. My custom enclosure for this is coming from Pedal Parts Plus, so I'm hoping to have everything working by the time it gets here. I'll report back any changes.
I replaced pot 8 but it still doesn't do anything ??? ??? ??? ??? ???
Can anyone help? I checked all my resistors, diodes, ICs, everything. It's all the right values, polarity. I even swapped out the "bad" pot for one that I tested with a multimeter and found fully functional.
The pot is fine but for some reason it's not doing its job while in the circuit, but only at pot 8. How is it possible for the LED to come on and sound to pass through when the pot is all the way off and the circuit has to travel through it before going through the LED? I need help bad. I can't find any dead spots in the circuits with an audio probe, just a few spots where I hear ticking instead of clean signal.
Help?
Anyone? Should there be this ticking in certain parts of the circuit when using the audio probe?
I built the lite version per the schematic provided and the wah is not very deep effect at all. Sounds almost like tremolo, which itself is cool, but not near the zvex demos. I'm not disappointed just wonder what I can try to improve this. I used a vactrol vtl5c9 as recommended it the BOM.
I might try to take a video today to explain better.
Great project so far and fun to build. It all fits in a 125b but I haven't wired the ins outs and footswitches.
4 6 8 and random work great.
Bump. Any input welcome.
Quote from: LaceSensor on November 18, 2011, 08:27:47 AMthe wah is not very deep effect at all. Sounds almost like tremolo, which itself is cool, but not near the zvex demos. I'm not disappointed just wonder what I can try to improve this. I used a vactrol vtl5c9 as recommended it the BOM.
4 6 8 and random work great.
I've found the same to be true. The wah on mine is not prominent at all...
Ahh sorry, I haven't seen this one in a while.
For deeper wah effect I would look up a vactrol or an LDR with a larger resistance sweep for the same range of light input. I think vactrol lists the resistances as a function of led forward current which is a handy measure. Also I would look at the wah circuit and try to tweak some of the filter values to maybe change the bandpass width of the filter and the center frequency range. Should just e swapping out caps and resistors. I would try to do a manual sweep with just a pot instead of a vactrol and try to find if you need to optimize the control resistance to a certain value.
Quote from: insomniac2295 on November 15, 2011, 03:11:58 AM
Anyone? Should there be this ticking in certain parts of the circuit when using the audio probe?
Yes, because half of the circuit is is essentially digital logic (the clock and sequencer) there is no audio signal passing through it. The clicks are just the pulses the oscillator is sending to tell the vactrol when you change the resistance value. As long as the clicks aren't coming through annoyingly strong in the audio signal at your amp then you are fine.
So is it still popping in the audio signal when it gets to pot 8? Does the LED for step 8 act normally? I guess it could be resetting the clock cycle before it gets to step 8 but that seems unlikely since the 8th step reset is hardwired on the PCB. If the LED for step 8 lights up I have no idea what could be wrong with it, past that point everything is hard mounted on the PCB and any defects past there would have bad effects on every other part of the circuit as well. Very strange issue you have here. Does the 4-8-6 switch and random functions work okay? When in 4 or 6 mode are there any weird issues with the operation?
And on another note, take a look near the bottom of this geofx page:
http://www.geofex.com/article_folders/wahpedl/wahped.htm#twintee (http://www.geofex.com/article_folders/wahpedl/wahped.htm#twintee)
The wah type is called a twin-t. I would search around and see if you cant tweak the values to increase the depth of the wah effect.
Quote from: JakeFuzz on November 20, 2011, 05:38:01 PM
Yes, because half of the circuit is is essentially digital logic (the clock and sequencer) there is no audio signal passing through it. The clicks are just the pulses the oscillator is sending to tell the vactrol when you change the resistance value. As long as the clicks aren't coming through annoyingly strong in the audio signal at your amp then you are fine.
So is it still popping in the audio signal when it gets to pot 8? Does the LED for step 8 act normally? I guess it could be resetting the clock cycle before it gets to step 8 but that seems unlikely since the 8th step reset is hardwired on the PCB. If the LED for step 8 lights up I have no idea what could be wrong with it, past that point everything is hard mounted on the PCB and any defects past there would have bad effects on every other part of the circuit as well. Very strange issue you have here. Does the 4-8-6 switch and random functions work okay? When in 4 or 6 mode are there any weird issues with the operation?
Ahhh, that clicking thing makes much more sense now, thanks!
I'm not sure if it's still popping when it gets to pot 8. The LED for step 8 works normally in the sense that it lights up when it should. However, turning pot 8 down does not affect the sound coming through pot 8 nor does it decrease the brightness of pot 8.
The 4-8-6 switch works fine. No apparent issues there. I'm glad I'm not the only one who thinks I have a very bizarre problem! If I can get around to it, I may post a video to better demonstrate the problem.
Is it still clicking overall though, not necessarily when it gets to pot 8?
Looking at the schematic the only thing I can think of that would cause the step 8 LED to stay on is if the resistance value of the pot is too low or more likely there is something wrong with either the value or the connection at R19. Check R19 to make sure it is not very large and that one of the sides of R19 is connected to ground (use the continuity tester on your DMM).
I suspect this because if R19 is too large (infinity if it is not connected to ground) the voltage divider doesn't produce the correct division ratio and the LED always see's a large enough voltage to stay fully lit. Same story if the pot value is too low just the other way around.
Quote from: JakeFuzz on November 21, 2011, 03:23:43 AM
Is it still clicking overall though, not necessarily when it gets to pot 8?
Looking at the schematic the only thing I can think of that would cause the step 8 LED to stay on is if the resistance value of the pot is too low or more likely there is something wrong with either the value or the connection at R19. Check R19 to make sure it is not very large and that one of the sides of R19 is connected to ground (use the continuity tester on your DMM).
I suspect this because if R19 is too large (infinity if it is not connected to ground) the voltage divider doesn't produce the correct division ratio and the LED always see's a large enough voltage to stay fully lit. Same story if the pot value is too low just the other way around.
Haven't worked on this project in a while, but something just occurred to me:
Could it be possible that this problem is being caused by the fact that I used high brightness 5mm LEDs instead of the 3mm LEDs used in other builds of this pedal?
yes, it could be that.
LEDs, because they are diodes, have different forward voltages depending on the size and colour. If you're using one of a different size, type and colour could result in atypical function. In theory. It could also work just fine.
Jacob
Quote from: jkokura on December 08, 2011, 09:21:17 PM
yes, it could be that.
LEDs, because they are diodes, have different forward voltages depending on the size and colour. If you're using one of a different size, type and colour could result in atypical function. In theory. It could also work just fine.
Jacob
Hmmmm.... i am using 4 different color high brightness 5mm LEDs. Any suggestions for a new resistor value for the LEDs? Or at least a starting point?
Quote from: insomniac2295 on December 08, 2011, 09:55:45 PM
Quote from: jkokura on December 08, 2011, 09:21:17 PM
yes, it could be that.
LEDs, because they are diodes, have different forward voltages depending on the size and colour. If you're using one of a different size, type and colour could result in atypical function. In theory. It could also work just fine.
Jacob
Hmmmm.... i am using 4 different color high brightness 5mm LEDs. Any suggestions for a new resistor value for the LEDs? Or at least a starting point?
The first thing I would do is remove the vactrol you have in there and replace it with sockets. Then I would put in an LED so you can visually monitor what is going on when you get to step 8. Remember the intensity of light from this LED directly changes your wah signal. From there you can see if it is more dim than the other steps and make the appropriate changes.
Quote from: JakeFuzz on December 08, 2011, 10:28:37 PM
Quote from: insomniac2295 on December 08, 2011, 09:55:45 PM
Quote from: jkokura on December 08, 2011, 09:21:17 PM
yes, it could be that.
LEDs, because they are diodes, have different forward voltages depending on the size and colour. If you're using one of a different size, type and colour could result in atypical function. In theory. It could also work just fine.
Jacob
This is a great idea! I just did this little test and came to the conclusion that the 4th and 8th step of the sequence are brighter than the rest. It just so happens that they are both red LEDs. Now, help a newbie out- If the 4th and 8th step in the sequence light up brighter, that means that i should increase the resistance on those two steps of the sequence on the pot board?
Hmmmm.... i am using 4 different color high brightness 5mm LEDs. Any suggestions for a new resistor value for the LEDs? Or at least a starting point?
The first thing I would do is remove the vactrol you have in there and replace it with sockets. Then I would put in an LED so you can visually monitor what is going on when you get to step 8. Remember the intensity of light from this LED directly changes your wah signal. From there you can see if it is more dim than the other steps and make the appropriate changes.
Depends on the LED and resistor.
What I would do is setup a bread board. Run your 9V along the + rail, and then your 4 LEDs between the - rail for the negative lead and any 4 strips with the positives. I would then start at whatever the value of resistor is called for in the dig dug and put one in between the + rail and each of the LED + leads. Once that's done, check out the relative brightnesses. I bet those reds will be brighter. Start raising the limiting resistor by a few k at a time until you have equal brightness all the way along. Lower or raise any other colours you need to, and you'll have your answer.
Jacob
anyone build one of these that actually sounds like a wah pedal yet?
Mine does a good seek trem impression to be honest.
Hi
Ive now socketed the Vactrol and tried
vtl 5c9
vtl 5c3
NSL - 32
and all perform the same
Anyone know how to make it wah and not trem?
Thanks