Just read that document by Infineon and some filter theory to see why "coils only" is not the right way. If one does not want to bother the 4 x BLE32PN300SN1L ferrite beads and 2 x 1 nF MKS/MKT are minimal protection. Any choice for coils will be more complex and time consuming certainly when not follows the recommendations of Infineon. No filtering or practically no way to add filtering in a ready made product is a no go for me.
Hence the search for MA12070 devices that do have the minimum of necessary bells and whistles so I made a small list of criteria. 1 to 4 are absolutely necessary IMHO to weed out the real bad ones, 5 and 6 are nice to haves:
1. Either beads or coils and caps or the PCB pads to replace/add those.
2. Decent way of converting unbalanced to balanced as it is a necessity for MA12070 to perform OK.
3. PCB layout as recommended by Infineon.
4. Possibility to replace class III input ceramic caps to X7R ones/film caps/wires.
5. Possibility to replace class III decoupling caps to X7R/film ones.
6. Possibility to replace the class III "flying" capacitors for X7R/film ones.
The impression is that Chi-Fi manufacturers of the cheapest products just use parts that resemble what should be used (and no one complains anyway). Specifically the class III caps are the cheapest one can find and also the worst available. Maybe it is better not to know
The chip must therefor do something really well in such an environment of cheapness.
Hence the search for MA12070 devices that do have the minimum of necessary bells and whistles so I made a small list of criteria. 1 to 4 are absolutely necessary IMHO to weed out the real bad ones, 5 and 6 are nice to haves:
1. Either beads or coils and caps or the PCB pads to replace/add those.
2. Decent way of converting unbalanced to balanced as it is a necessity for MA12070 to perform OK.
3. PCB layout as recommended by Infineon.
4. Possibility to replace class III input ceramic caps to X7R ones/film caps/wires.
5. Possibility to replace class III decoupling caps to X7R/film ones.
6. Possibility to replace the class III "flying" capacitors for X7R/film ones.
The impression is that Chi-Fi manufacturers of the cheapest products just use parts that resemble what should be used (and no one complains anyway). Specifically the class III caps are the cheapest one can find and also the worst available. Maybe it is better not to know
The chip must therefor do something really well in such an environment of cheapness.
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No caps after the coils (LC remember?) which is left on your picture. They could be added using the L+ and L-, R+ and R- pads when one knows the properties of the coils. If one wishes to do stuff right that involves measuring the coils, recalculation, remeasuring etc. The Aiyima exhibits a loud whine after switching it on. Still have to find out why that is. Not over the loudspeakers but through its casing.
https://electronicbase.net/low-pass-filter-calculator/
BTW an extra criterium could be:
7. Decent way of creating a low noise 5V for DVDD.
https://electronicbase.net/low-pass-filter-calculator/
BTW an extra criterium could be:
7. Decent way of creating a low noise 5V for DVDD.
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You can let solder the PCB manifacture the IC on it. I like to see and build your PCB design.
You won't as it does not exist as explained in 1 sentence. I am used to having stuff produced but in this case the costs are IMO not worth the trouble when comparing.
For instance: I paid 60 Euro for the Aiyima A8, power supply and shipping included. No way I can make even a PCB with parts for that price. If being done then choices for SMPS and other costcutting stuff also comes into play and the design will be a 1 day fly with main feature MA12070 like Chi-Fi devices. For an overall good quality design it will simply be not economically viable. Of course I am not so strict in the economical teachings as I use expensive transformers and linear power supplies as standard but that is audio and the forthcoming desire to raise the bar with regards to quality. This module seemed a good combination of factors and it easily integrates according design requirements:
https://www.audiophonics.fr/en/ampl...lifier-module-ma12070-160w-4-ohm-p-14732.html
For instance: I paid 60 Euro for the Aiyima A8, power supply and shipping included. No way I can make even a PCB with parts for that price. If being done then choices for SMPS and other costcutting stuff also comes into play and the design will be a 1 day fly with main feature MA12070 like Chi-Fi devices. For an overall good quality design it will simply be not economically viable. Of course I am not so strict in the economical teachings as I use expensive transformers and linear power supplies as standard but that is audio and the forthcoming desire to raise the bar with regards to quality. This module seemed a good combination of factors and it easily integrates according design requirements:
https://www.audiophonics.fr/en/ampl...lifier-module-ma12070-160w-4-ohm-p-14732.html
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Mmmm, .3 ohms from Cap c20 to output of coil L3 .
Unless the damaged chip plays a roll here we have a filter
For me it is about price/quality ratio with emphasis on the latter item so no SMPS for instance. I would like to see that design when it really costs 20 Euro. A quality design in all aspects with best parts for the purpose, no gadget like device. The nice thing of Chi-Fi is that many only got to know this chip because of the cheap gadget devices that lack a necessary feature here and there
. Only the power transformer for a decent design cost me 25 Euro today and this was a 50% discount transformer. Normally it would be 50 Euro and then one needs to add costs for rectifiers/filter cap/regulator/heatsink to that. Casing cost is also relatively high nowadays.Rethink that one
Nesha, do you have a link? Seems they knew how to design a device.
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Don't make me think on my old da
Don't make me think in my old days.Rethink that one
Aliexpres, but i have problem to pass a link ???🤔For me it is about price/quality ratio with emphasis on the latter item so no SMPS for instance. I would like to see that design when it really costs 20 Euro. A quality design in all aspects with best parts for the purpose, no gadget like device. The nice thing of Chi-Fi is that many only got to know this chip because of the cheap gadget devices that lack a necessary feature here and there
Rethink that one
Nesha, do you have a link? Seems they knew how to design a device.
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