Madbean Zero Point SDX not working as it should

[pietro_moog]

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.

[ggarms]

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.

[Battery Acid]

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?

[pietro_moog]

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.

[ggarms]

Sorry, I was at work when responding. I meant the pair of 914s

[pietro_moog]

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?

[jimilee]

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.

[Shrtyska9]

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

[ggarms]

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.

[Battery Acid]

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!

[pietro_moog]

i'm interested in the results, since i don't have  50k a right now and i have to order it. thanks

[m-Kresol]

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.

[pietro_moog]

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

[Battery Acid]

I don't see how it would cause the problems I'm having in mine. It should just give twice the total delay time

[pietro_moog]

i did  the substitution, and i solved everything with a log pot. it's ok, sounds good.