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Madbean Zero Point SDX not working as it should

Started by Battery Acid, November 16, 2013, 10:58:08 PM

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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?
Complicate it doesn't make it wrong

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

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?

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.
Pedal building is like the opposite of sex.  All the fun stuff happens before you get in the box.

Shrtyska9

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

Richard

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!
Complicate it doesn't make it wrong

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.
I build pedals to hide my lousy playing.

My projects are labeled Quantum Effects. My shared OSH park projects: https://oshpark.com/profiles/m-Kresol
My build docs and tutorials

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
Complicate it doesn't make it wrong

pietro_moog

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