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I designed an open source, fully analog IEM Amplifier!
I'm a highschool student in Australia who's really interested in sound engineering and recently decided to start designing a custom IEMA (In ear monitor amplifier) as a cheap and opensource alternative to the Behringer P2.
For context, I do live sound at different gigs around where I live and I wanted a cheap and flexible wired IEM beltpack for when I perform that's not the Behringer P2 so I decided to make my own from scratch using analog circuits! I first built the PCB in Kicad and then modelled a case in fusion and then got my renders through blender!
No proper GND plane is not ideal. The ferrite could also be problematic. The 47uF caps also seem excessive considering C13 having a cutoff at around 60 Hz.
Edit: The MCP73831 EP is also not connected to GND which is against datasheet recommendations and will be problematic at higher charging speeds.
They never said it wasn’t good, there is nothing to be learned for OP if every Comment would just be something along the lines of “amazing 🤩” like it has become the case on a lot of other social-media sites.
OP did a great Job considering they are a Highschool student, and thanks to hints and some critiques they will probably become a beast in a few years :)
Nobody claimed its not fantastic. The OP of this comment simply pointed out mistakes that would lower the quality of the project. Nobody gets their first low-noise or RF PCB right. It takes many iterations and know-how. And in fact, I did enjoy receiving critique when I started out and to be honest still today. I am not the top individual in RF and neither am I approaching it, so as far as I am concerned any advice is always welcome, that is how you learn. The advices given by the commenter were clearly in good faith and objective. I dont see the problem.
You have no warning with this circuit when you start overdischarging your batteries.
Be aware that you can unknowingly damage your li ion batteries to the point of irreparability.
Deep discharge does not cause thermal runaway.
It is just going to break.
A boost converter with a smaller hysteresis on the en pin, and a voltage divider could also do the trick.
Deep discharge increases the rist of a burning battery a lot because it causes the growing of dendrites. Exactly for this reason you should comsider them as totaled and never recharge them after overdischarge.
I planned the design to use a battery with a BMS/protected LiPo, however for v2 I'll be sure to add a built in BMS as it just makes the design better and safer overall :D
In multi-cell setups I get the necessity for BMS for monitoring and balancing. With a single cell that has integrated PCM, what would the benefit of additional BMS be?
The battery protection isn't a problem as my original design intented to use a protect lipo, as for the 4 layers - 2 layers is sufficient as for an iem on stage 80db of signal to noise ratio is totally fine :D
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u/MainioSukkka 7d ago edited 7d ago
No proper GND plane is not ideal. The ferrite could also be problematic. The 47uF caps also seem excessive considering C13 having a cutoff at around 60 Hz.
Edit: The MCP73831 EP is also not connected to GND which is against datasheet recommendations and will be problematic at higher charging speeds.