Timeline for Strange AD8512A op amp behavior
Current License: CC BY-SA 3.0
15 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Feb 4, 2018 at 0:36 | vote | accept | Anonymous | ||
| Jun 13, 2017 at 7:58 | comment | added | Anonymous | @laptop2d Crossing done, second channel / headphone works properly. Already ordered new devices. By the way, ADI refused in telling me if these faulty ones counterfeit or not. They just said that I bought them from wrong place. Let's see if shop I bought them in is caring about its reputation. | |
| Jun 13, 2017 at 4:59 | comment | added | Voltage Spike♦ | Yeah, something is up with the other channel. The nice thing is, you have two channels and if one is working you know its not the schematic. I would do one of two things: 1) cross the outputs of the drivers to make sure its not the headphones or something else. 2) Replace the non working op amp | |
| Jun 12, 2017 at 21:21 | comment | added | Anonymous | As per upper circuit, after op-amp resistor of 330 Ohm, then 10uF / 25V bipolar capacitor, and then 30 Ohm headphones. I have sound in one ear, and no sound in another. | |
| Jun 12, 2017 at 21:17 | comment | added | Voltage Spike♦ | @Anonymous What is your load? | |
| Jun 12, 2017 at 21:16 | comment | added | Anonymous | @laptop2d added scope diagrams to the question. Very interesting observations! | |
| Jun 12, 2017 at 21:04 | comment | added | Voltage Spike♦ | @mbrig its canadian customs, when I was there it took 3 days to send mail to the US and 2 weeks to get it back | |
| Jun 12, 2017 at 20:32 | comment | added | mbrig | @anonymous The op-amp could be oscillating wildly at a high frequency and this probably wouldn't be heard. A scope is always a good check. | |
| Jun 12, 2017 at 20:30 | comment | added | mbrig | "Its probably better to do a simple two layer PCB than spend hours of debugging", I've always believed this, and I try to go this route, but man would it be easier if I lived in the US. For some reason being Canadian adds 2-3 weeks to pcb shipping time unless I spend $50+ in shipping :( (not OP, btw) | |
| Jun 12, 2017 at 20:28 | comment | added | Anonymous | Is it enough that I do not hear anything? I put positive audio level in, and it outputs negative level of nothing. Of course I can try scope, but not sure it gives any informative info. Second op-am which I desoldered is even of much bizarre behavior. | |
| Jun 12, 2017 at 20:26 | comment | added | Voltage Spike♦ | Since its a voltage follower you should see the same thing on the input and output of the follower, if you don't see this then you have a problem. if you like the answer then upvote | |
| Jun 12, 2017 at 20:25 | comment | added | Anonymous | I have scope but how it can help me? With scope I can see dynamic level of signal; if no signal it will not show anything useful... | |
| Jun 12, 2017 at 20:24 | comment | added | Voltage Spike♦ | If you don't have a scope get a cheap digital one off ebay I think you can pick them up for 30$ that work ok under 50Mhz | |
| Jun 12, 2017 at 20:23 | comment | added | Anonymous | Thank you so much for your answer. (1) I will order new ones (hopefully ADI's conclusion about chip counterfeit or not will arrive tomorrow); just updated questing posting latest pic of the device. I though as you do - that if there're some oscillations or parasitic effects, I would anyway hear the sound. Currently I hear nothing through op-amp with pins 1-2-3. One ear has sound, another does not, both are having same circuit, but involving different op-amp instances. | |
| Jun 12, 2017 at 20:05 | history | answered | Voltage Spike♦ | CC BY-SA 3.0 |