Some 18V secondary vac tranfo can shoot up to 21-22V and fails the 20V tantalum caps, may be it is safer to use 47uF 25v MLCC on C36 C37 instead?
Invalid Request
It's may be because the PCB is false!
A connections to ground of the C22 and C23 missing!
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I just try my dac board with only tps regs plugged and I measured first, -12V and 2V at ouput... After looking the schematic, I don't believe myself to that huge error.
I have scratched soldermask and made contact and know I have +12V and -12V!
...it's just the beginning, and don't know what the futur reserve!
I have scratched soldermask and made contact and know I have +12V and -12V!
...it's just the beginning, and don't know what the futur reserve!
There were a bunch of Indians who got the boards first who reported successful builds and favourable SQ... You don't have a closeup photo of the board. That should reveal if the trace was there. Does it show on the photos syllable or someone else uploaded...
I believe syllable and heartwinter is the one and same...
Regards
I believe syllable and heartwinter is the one and same...
Regards
This version of the board clearly hasn't been tested, so it's worth checking the rest very carefully. A couple of other things that perhaps are not bugs, but are less than optimal:
1. The output balanced to SE opamp doesn't have a buffering resistor on its output - it needs 47 - 100 ohm.
2. All opamps have the ground plane covering them. This will add capacitance to the inputs, possibly making high speed parts unstable, although it will probably be OK for the listed LME49720. I'm planning to use ADA4898 for I/V, so have cut away the ground plane.
1. The output balanced to SE opamp doesn't have a buffering resistor on its output - it needs 47 - 100 ohm.
2. All opamps have the ground plane covering them. This will add capacitance to the inputs, possibly making high speed parts unstable, although it will probably be OK for the listed LME49720. I'm planning to use ADA4898 for I/V, so have cut away the ground plane.
I got 2 boards and one for my friend. I have not started the build but my friend did during the last weekend and just fry the 4700 too, he check all the soldering had not discovered any mistake. He left the jump open first and check the 4700 PS reg and both were outputing fine on + and - rails, he finally soldered the SOIC 4562 opamp and the neg rail is not producing the correct voltage and seems dead.
Now, how can he dismount the 4700? Can anyone share the experience ?
Now, how can he dismount the 4700? Can anyone share the experience ?
Dismouting the 4700, he should starting by remove all the solder at the back of the chip! (bottom side of the pcb). After, cut it with this kind of thing!
Good luck!
Good luck!
If it is "probably OK" for LME49720, then you don't need to remove the GND plane (even if you use another opamp). Better first build it according the BOM, then measure and listen before doing any mods at all.
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