Hi there guys,
I had a ZPSDX board lying around for some time and decided to finish it today. I had triple checked everything, resistor values, capacitor positions and values, diodes, etc etc, and this think sounds plain weird. I can't get it to delay like erm, a delay pedal should. It sounds like a reverb, and with the feedback at, I don't know, 1/3 of its turn, it starts self oscilating like crazy. I already checked both PT2399 on my Sea Urchin, and they're both working just fine there. The only substitution I have made is 100kB for the mix pot, since I don't have any spare 50kB. If anyone can point me out a direction, I would love to rock this thing out!
(http://i1127.photobucket.com/albums/l630/batteryacidtea/WP_20131116_0011_zpsc9f4a886.jpg)
(http://i1127.photobucket.com/albums/l630/batteryacidtea/WP_20131116_0092_zps3a027441.jpg)
(http://i1127.photobucket.com/albums/l630/batteryacidtea/WP_20131116_0021_zps2b773288.jpg)
(http://i1127.photobucket.com/albums/l630/batteryacidtea/WP_20131116_0061_zpsd9076a6f.jpg)
So is your complaint about the sound or the runaway oscillations? If you hit the slam switch does it stop? As far as the sound, I have found the reverb type sound to be normal unless you use the tape selection. I don't care for it either, but that's how it sounds as opposed to the sea urchin or even the cave dweller.
No no, I know it is not working as it should. The delay knob changes the pitch of the sound as I turn it, but I can't get it to repeat notes like my DBD clone, it just oscilates like crazy or gives me a very short slapback. And it happens in every mode, but one of them (wich I don't remenber right now) needs more feedback to oscilate, but doesn't sound like a delay at all. I can hear the ambience and all, it just sounds like a veeeery short delay
Well that's a neat trick. The delay changes the pitch? are you sure that's the delay and not the rate knob for the modulation? Got voltages and what not?
Oh, I think every pt2399 based delay changes the pitch when you turn the delay knob, the MidFi Electronics Pitch Pirate does this. I'll measure the voltages later and post it here! Thanks in advance
As much as I'd like to, I really can't help you out right now as my zpsdx board is scornfully staring at me still unpopulated, but I'll keep my eye out on this thread. I hope for your sake you get to the bottom of this before I put the project together... ;D
Quote from: Battery Acid on November 16, 2013, 11:45:46 PM
Oh, I think every pt2399 based delay changes the pitch when you turn the delay knob, the MidFi Electronics Pitch Pirate does this. I'll measure the voltages later and post it here! Thanks in advance
oh well while you're turning the knob, yes. I thought you meant something else. My bad. As far as the runaway oscillations, does pressing the slam switch make it stop? I had that issue, took three switches before I found one that was nc
Solder a 100k resistor across lugs 1 and 3 of the 100kB Mix pot to bring it to 50kB (correct specced value.)
Also, the build doc states to omit R45, which you've soldered onto the board.
Quote from: alanp on November 17, 2013, 12:24:15 AM
Also, the build doc states to omit R45, which you've soldered onto the board.
+1! Sharp eye Alan.
I don't think the 100k pot could be the cause for the problems, but I completely forgot 'bout r45, I'll try it right away! Thank you!
In the last pic, it looks like you might have damaged the board just above D2, D3 and C47, left of C48. Are the traces in that area still connected?
Paul
Well, I just snipped out R45 and no dice, still acting like a reverb and oscilating like crazy with the feedback pot after 1/3 of the turn. Any clue 'bout the area of the circuit I would be paying more atention? I mean, I know it's a verified circuit (like everything madbean sells) and it sounds pretty good, at least on the user's demos. I think I'm just tired from messing with this circuit all day long, maybe I'll take on day or two away from this pedal, but I'm open for ideas 'bout whats causing it to act like this
Quote from: DutchMF on November 17, 2013, 07:43:03 AM
In the last pic, it looks like you might have damaged the board just above D2, D3 and C47, left of C48. Are the traces in that area still connected?
Paul
I've just checked the board, at first glance it seems to be ok. I'll check the continuity with the Multimeter tomorrow, but I have a strong feeling 'bout the problem being caused by some wrong resistor or capacitor value. But it's just a guess
I checked the continuity and it's ok... tomorrow I'll measure the voltages and post here. do you guys have any other ideas?
Ok, here are the voltages...
IC 1:
Pin 1: 4.70
Pin 2: 4.30
Pin 3: 4.67
Pin 4: 0.00
Pin 5: 4.68
Pin 6: 0.00
Pin 7: 4.70
Pin 8: 9.44
IC 2:
Pin 1: 5.05
Pin 2: 2.51
Pin 3: 0.00
Pin 4: 0.00
Pin 5: 2.79
Pin 6: 2.43
Pin 7: 0.84
Pin 8: 0.90
Pin 9: 2.51
Pin 10: 2.52
Pin 11: 2.52
Pin 12: 2.51
Pin 13: 2.52
Pin 14: 2.53
Pin 15: 2.52
Pin 16: 2.52
IC 3:
Pin 1 : 5.06
Pin 2: 2.51
Pin 3: 0.00
Pin 4: 0.00
Pin 5: 2.73
Pin 6: 2.42
Pin 7: 0.87
Pin 8: 0.93
Pin 9: 2.52
Pin 10: 2.52
Pin 11: 2.52
Pin 12: 2.52
Pin 13: 2.52
Pin 14: 2.52
Pin 15: 2.52
Pin 16: 2.52
IC 4:
Pin 1: 4.71
Pin 2: 4.72
Pin 3: 4.66
Pin 4: 0.00
Pin 5: 4.69
Pin 6: 4.72
Pin 7: 4.72
Pin 8: 4.72
Pin 9: 4.72
Pin 10: 4.63
Pin 11: 9.44
Pin 12: 2.30
Pin 13: 4.72
Pin 14: 4.72
I just checked every resistor in the circuit, and all the codes match. Also looked for solder bridges, but no dice. If any one can give me any direction, where I should be looking at, it would be VERY helpfull, I'm very frustrated right now.
i have a similar problem. my delay works fine but the feedback pot is going into crazy self oscillation at 1/3 of the rotation. the rest is ok, but i can't have much repeats.
Check the diodes near the feedback pot, I can't remember which ones they are numbered on the schem. I was only getting one repeat and that was my issue! It doesn't sound like that exact same problem you're having but it's worth a go.
do you mean, the kind of diodes? those are 1n914, I think they are what the scheme says, isn't? Or do you had problems with the voltages?
my diodes are in the circuit and they seem fine. the circuit is good. my idea is that the pt2399 must be selected.
the ones i have they work good in my sea urchin circuit, but maybe not together. i don't know, that's the only point i see. i'll check tomorrow with a few spares i have.
Sorry, I was at work when responding. I meant the pair of 914s
Quote from: Battery Acid on November 21, 2013, 05:52:27 AM
Ok, here are the voltages...
IC 1:
Pin 1: 4.70
Pin 2: 4.30
Pin 3: 4.67
Pin 4: 0.00
Pin 5: 4.68
Pin 6: 0.00
Pin 7: 4.70
Pin 8: 9.44
IC 2:
Pin 1: 5.05
Pin 2: 2.51
Pin 3: 0.00
Pin 4: 0.00
Pin 5: 2.79
Pin 6: 2.43
Pin 7: 0.84
Pin 8: 0.90
Pin 9: 2.51
Pin 10: 2.52
Pin 11: 2.52
Pin 12: 2.51
Pin 13: 2.52
Pin 14: 2.53
Pin 15: 2.52
Pin 16: 2.52
IC 3:
Pin 1 : 5.06
Pin 2: 2.51
Pin 3: 0.00
Pin 4: 0.00
Pin 5: 2.73
Pin 6: 2.42
Pin 7: 0.87
Pin 8: 0.93
Pin 9: 2.52
Pin 10: 2.52
Pin 11: 2.52
Pin 12: 2.52
Pin 13: 2.52
Pin 14: 2.52
Pin 15: 2.52
Pin 16: 2.52
IC 4:
Pin 1: 4.71
Pin 2: 4.72
Pin 3: 4.66
Pin 4: 0.00
Pin 5: 4.69
Pin 6: 4.72
Pin 7: 4.72
Pin 8: 4.72
Pin 9: 4.72
Pin 10: 4.63
Pin 11: 9.44
Pin 12: 2.30
Pin 13: 4.72
Pin 14: 4.72
I just checked every resistor in the circuit, and all the codes match. Also looked for solder bridges, but no dice. If any one can give me any direction, where I should be looking at, it would be VERY helpfull, I'm very frustrated right now.
my voltages look like yours, so there's nothing wrong. i tried 12 different pt2399 in my build, but i gained almost nothing. all in all i don't think there nothing wrong. i think it is just the pedal. maybe a 50k log pot could ease the situation, but i wonder: do other people's builds have this exact problem?
Mine and many do, the problem with mine was when I would hold down the slam switch it would stop, so I replace it with a nc switch instead of an no, that worked for me.
Quote from: pietro_moog on November 23, 2013, 08:11:57 PM
Quote from: Battery Acid on November 21, 2013, 05:52:27 AM
Ok, here are the voltages...
IC 1:
Pin 1: 4.70
Pin 2: 4.30
Pin 3: 4.67
Pin 4: 0.00
Pin 5: 4.68
Pin 6: 0.00
Pin 7: 4.70
Pin 8: 9.44
IC 2:
Pin 1: 5.05
Pin 2: 2.51
Pin 3: 0.00
Pin 4: 0.00
Pin 5: 2.79
Pin 6: 2.43
Pin 7: 0.84
Pin 8: 0.90
Pin 9: 2.51
Pin 10: 2.52
Pin 11: 2.52
Pin 12: 2.51
Pin 13: 2.52
Pin 14: 2.53
Pin 15: 2.52
Pin 16: 2.52
IC 3:
Pin 1 : 5.06
Pin 2: 2.51
Pin 3: 0.00
Pin 4: 0.00
Pin 5: 2.73
Pin 6: 2.42
Pin 7: 0.87
Pin 8: 0.93
Pin 9: 2.52
Pin 10: 2.52
Pin 11: 2.52
Pin 12: 2.52
Pin 13: 2.52
Pin 14: 2.52
Pin 15: 2.52
Pin 16: 2.52
IC 4:
Pin 1: 4.71
Pin 2: 4.72
Pin 3: 4.66
Pin 4: 0.00
Pin 5: 4.69
Pin 6: 4.72
Pin 7: 4.72
Pin 8: 4.72
Pin 9: 4.72
Pin 10: 4.63
Pin 11: 9.44
Pin 12: 2.30
Pin 13: 4.72
Pin 14: 4.72
I just checked every resistor in the circuit, and all the codes match. Also looked for solder bridges, but no dice. If any one can give me any direction, where I should be looking at, it would be VERY helpfull, I'm very frustrated right now.
my voltages look like yours, so there's nothing wrong. i tried 12 different pt2399 in my build, but i gained almost nothing. all in all i don't think there nothing wrong. i think it is just the pedal. maybe a 50k log pot could ease the situation, but i wonder: do other people's builds have this exact problem?
Yeah Juansolo posted about sticking a 50k log in the feedback position for the zp DD in the mods section.
Sent from my VM670 using Tapatalk 2
Oh yeah, i forgot I had that problem too Jimi. I either ordered or was shipped the wrong momentary switch. So I was always oscillating. except when I held slam. Simple fix.
Let's see, I'll try to stick a 50kA in there. It's kinda weird to hear this is a common problem, since I've seen some demos of the pedal and it sounds pretty good and does the standard delay stuff :(
I'll try it and post the results here!
i'm interested in the results, since i don't have 50k a right now and i have to order it. thanks
I'm building mine atm, but I have to redo some of the drillings before I can proceed. I have to say I'm quite anxious to encounter the same problems... hope that everything turns out as planed. I'll keep you updated when I finish, hopefully in the next 2-3 days.
do you guys see any major problem if i use a 100k a pot for the repeats?
i have one spare, but i didn't desolder anything yet
I don't see how it would cause the problems I'm having in mine. It should just give twice the total delay time
i did the substitution, and i solved everything with a log pot. it's ok, sounds good.
I'll try it right now
Well, fuck it. I'll "just" give up. I tried everything, new diodes, checked every damn resistor value, checked for unwanted solder bridges, changed the pot taper, and it still acting like a silly reverb. I'll record a video just for the hell of it, but I give up
Well, here it is
In the video I tweak both Delay and Feedback knobs. It kinda sucks, because I already drilled and finished an enclosure, heh.
Hm, isn't that the GHOST switch what you can hear?
It's off in the video. When it's on, it just oscilates like crazy and faster
oh come on, you can solve this, no negative thinking! do this:
take the path mod off, take the modulation off and remove the ic, set the deep mode and remove the ic.
basically you removed half the circuit. now set mix at zero, do you have normal signal? good.
so you are left with just a 1/4 of the circuit. do you have a log pot for feedback? good.
now: can you read the schematic? just visual check your caps on the second part of the pt2399, i mean like the 2n2 caps going from pin 16 to pin 15 on the others. do you understand? then, did you check the pt2399s with some other circuit? or do you have some other pt2399 to try? if they are good your prom lies in the first prat of the pt2399s circuit. i mean the stuff attached to pin 1 to 8. most of them are capacitors, so you can visual-check.
are they good? then are the transistors working? check the resistors around them. are the values good?
check r48, which is the one that limits the delay time.
ps. i assumed you are not a mood and you have a multimeter, right?
Well, I'll take some rest before I try to mess again with this little mofo. Thanks for the tips! I do know how to read an schematic, I just don't know much about what does what in a delay pedal, guess is time to learn something new. I've already checked the capacitor and resistor values more than once, but I can do it again. I have tryied all my PT2399's in my Deep Blue Delay clone, and they all work (and I have a bunch, hehe). Think I'll have to try the transistors, will remove them all and put sockets in there. And I removed R45, but have to check R48. And yes, I have a multimeter, hehehe. I'm not exactly new in the pedal making business, and that's why I'm so frustrated hahaha.
and thanks very much for the tips, I'll give it a go and report back
Tonight I had the funniest dream! Madbean himself chimed it here and told me to look at the value of resistor x, and in the dream I took that resistor out and swaped for another, and it just happened to be an out of spec component, turned the pedal on and it was working! Dang, it was just a dream...
I woke up and started messing with the pedal. Started looking the things pietro_moog pointed out (thank you very much, by the way!). Swaped some capacitors I accidentally damaged with my soldering iron, checked all capacitor values, removed the transistors and installed new ones, now socketed, measured R48 with the multimeter, changed all the ic's - including new tested and working pt2399. Removed everything that didn't belong to the delay path, but once again, no dice. I plugged in my Deep Blue Delay just to be sure I'm not crazy and somehow forgot how a delay sounds, but yeah, it really doesn't work as it should. I know Brian is a pretty busy guy, but would be kinda nice of him to point were I should be looking at with more attention. I buy boards from madbean since the first klon board, there wasn't even a website at that point