Hi all, first post here after performing a search. There have been several similar topics but none that seem to have resolved the issue.
Recently built the Wish Klon Clone. I have power and sound and overall it sounds great!
But... the pedal produces a electronic buzz or hiss or crackle when low notes are played with high output pickups. This happens not only with the pedal on (which i could live with as it is less noticeable), but also in bypass mode, so it is distracting and doesn't sound great. I've tried it with multiple amps, power supplies, cables, etc.
As the issue happens with the switch on and off, i think it could be caused by some of the parts shared by the buffered bypass and on setting, but dont know what those would be.
Photos attached.
Pin measurements below:
IC1
1: 4.54
2: 4.54
3: 1.08
4: 0
5: 4.42
6: 4.53
7: 4.53
8: 8.97
IC2
1: 4.52
2: 4.54
3: 4.48
4: -8.9
5: 4.48
6: 4.54
7: 4.55
8: 16.81
7660s
1: 8.96
2: 4.54
3: 0
4: -4.36
5: -8.88
6: 4.35
7: 3.7
8: 8.96
Ive reached my limit of electronics knowledge here! Ive re-soldered any suspect connections but to no avail. Any help or suggestions are appreciated!
(https://i.postimg.cc/WDk516s0/20230103-170231.jpg) (https://postimg.cc/WDk516s0)
(https://i.postimg.cc/zbwpnzbB/20230103-170545.jpg) (https://postimg.cc/zbwpnzbB)
Whats up with that fractured looking opamp?
Quote from: Kevin Mitchell on January 13, 2023, 02:21:20 PM
Whats up with that fractured looking opamp?
Just surface scratches from the tweezers I used to pull it and put it back in when i was trying to diagnose.
There are a load of really bad TL072 op amps being sold that suffer from noise and crackle when driven hard.
I don't know where you got your TL072s from but I would suggest replacing them with genuine TI ones from trusted places like Mouser or Farnell.
Quote from: Dgsaudio on January 13, 2023, 10:35:31 AM
Pin measurements below:
IC1
1: 4.54
2: 4.54
3: 1.08
4: 0
5: 4.42
6: 4.53
7: 4.53
8: 8.97
I would like a schematic for reference but, even without one, pin 3 (non-inverting input) doesn't feel so good.. :icon_wink:
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Quote from: FSFX on January 13, 2023, 02:28:41 PM
There are a load of really bad TL072 op amps being sold that suffer from noise and crackle when driven hard.
I don't know where you got your TL072s from but I would suggest replacing them with genuine TI ones from trusted places like Mouser or Farnell.
They just came with the kit. They have the TI logo on there, but of course they could be counterfeit.
Quote from: Dgsaudio on January 13, 2023, 03:05:36 PM
Quote from: FSFX on January 13, 2023, 02:28:41 PM
There are a load of really bad TL072 op amps being sold that suffer from noise and crackle when driven hard.
I don't know where you got your TL072s from but I would suggest replacing them with genuine TI ones from trusted places like Mouser or Farnell.
They just came with the kit. They have the TI logo on there, but of course they could be counterfeit.
Personally, I would not trust them. I have seen lots of reports of people getting TL072 devices from places like Tayda that turned out completely unusable.
I have had TL072s from some places that have tested Ok at low levels but get a bit of a kink in the waveform when driven with larger signals. The genuine TI TL072s do not do that.
I would not trust any TL072s that come from China, or at least you need to thoroughly test them to see how they behave with a large range of signal levels.
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Quote from: FSFX on January 13, 2023, 06:47:54 PM
Quote from: antonis on January 13, 2023, 06:16:26 PM
That's exactly what I'd expect..
(maybe a bit lower but definately not lower than 3V, say..)
Anyway, why do you keep on about this trying to contradict everything I say whilst in fact the problem is a load of fake or inferior TL072 chips that exhibit the crackling sound that the OP originally reported.
Simple fact is that there are loads of bad TL072 chips being sold. This has been reported by many on the forums and in the Facebook groups.
I really appreciate the help from all parties and will order some new tl072s to see if that resolves the problem.
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Quote from: antonis on January 14, 2023, 04:48:34 PM
Quote from: FSFX on January 14, 2023, 04:36:51 PM
when you start being disrespectful and treating me like an idiot who doesn't know anything about electronics then you have crossed a RED LINE.
Are you sure you're addressed to the right person..?? :icon_eek:
Most definitely.
This is a Chinese water deer:
(https://www.animalspot.net/wp-content/uploads/2018/08/Chinese-Water-Deer.jpg)
It's a deer with fangs. It's shocking, right? It's also quite distracting and off topic. Can we move beyond Chinese water deer and useless bickering, please?
Quote from: EBK on January 14, 2023, 05:04:04 PM
It's a deer with fangs. It's shocking, right? It's also quite distracting and off topic. Can we move beyond Chinese water deer and useless bickering, please?
I told the OP exactly what the issue was with bad TL072s. I would have hoped that would be the end of it but someone else had other ideas that contradicted all the facts. I feel it is my duty to prevent beginners being fed with erroneous information.
What I posted regarding the inaccuracy of measuring the voltages of high impedance circuits with a DMM was intended to educate and inform about why people don't see the voltages they were expecting. I didn't expect to have somebody disputing what I wrote.
Quote from: FSFX on January 14, 2023, 05:10:17 PM
What I posted regarding the inaccuracy of measuring the voltages of high impedance circuits with a DMM was intended to educate and inform about why people don't see the voltages they were expecting.
...which seems reasonable.
Quote
I didn't expect to have somebody disputing what I wrote.
Perhaps you should. Obviously, not
always, but sometimes I've posted stuff here and been pulled up short by someone else. Sometimes I was right and they were mistaken, but often I was the one mistaken even if I couldn't see why at first. Certainly the process of investigating what the facts are and why someone sees the situation one way and you see it another is a useful process, and it needs to be conducted in a manner that everyone can remain happy with. Consider it a scientific endeavour, not a personal conflict.
Like that we can all learn something, which is why we're here.
I uhhh... I think the opamps are bad too.
"Wish kit" would be the big flag to me. Those type of bargains are typically not right one way or another. The integrity of the ICs would be most suspect, and the experienced will agree that they do not look right. Even the use of the outdated Intersil chip is questionable, but the voltages are there so... thats fine.
Dgsaudio, do let us know if the replacements fix the issues. It would help out those who come after you.