Hello!
I am currently building a Bluetooth portable speaker. Everything about the build was okay but there is one thing bothers me a lot, the Bluetooth receiver generates noise no matter what power source I connected it to.
The hum is in high frequency and the frequency goes up and down. Somehow the noise is a bit better when I turn the volume knob(b100k) all the way up, and somehow, the hum will eventually gone after powering up the speaker a while, leaving an acceptable white noise at the background like an old FM receiver. The noise also decreases a bit when it is streaming songs through Bluetooth, when the music stops, few seconds later the Bluetooth receiver sort of switch to idle mode(? and the high frequency noise is back again.
I did tons of searching on the internet to find the solution, and everyone solved the problem by using a dc-dc isolator, I did the same and it didn't work for me.
Because I can't do anything with it, I had to ask here. At this point, I wish I know the circuit design of those speakers from big companies. How JBL managed to get a very clean sound out of a Bluetooth module??
Anyway, here is the my circuit diagram.
sorry for the bad schematic, I am still new to this area.
I am currently building a Bluetooth portable speaker. Everything about the build was okay but there is one thing bothers me a lot, the Bluetooth receiver generates noise no matter what power source I connected it to.
The hum is in high frequency and the frequency goes up and down. Somehow the noise is a bit better when I turn the volume knob(b100k) all the way up, and somehow, the hum will eventually gone after powering up the speaker a while, leaving an acceptable white noise at the background like an old FM receiver. The noise also decreases a bit when it is streaming songs through Bluetooth, when the music stops, few seconds later the Bluetooth receiver sort of switch to idle mode(? and the high frequency noise is back again.
I did tons of searching on the internet to find the solution, and everyone solved the problem by using a dc-dc isolator, I did the same and it didn't work for me.
Because I can't do anything with it, I had to ask here. At this point, I wish I know the circuit design of those speakers from big companies. How JBL managed to get a very clean sound out of a Bluetooth module??
Anyway, here is the my circuit diagram.
An externally hosted image should be here but it was not working when we last tested it.
sorry for the bad schematic, I am still new to this area.
What value of pot?
I use 2K...helps keep impedance of audio line low to reduce noise pickup.
(as well as isolated dc-dc on BT supply)
Others have used an audio isolation transformer between BT and amp.
Good Luck
I use 2K...helps keep impedance of audio line low to reduce noise pickup.
(as well as isolated dc-dc on BT supply)
Others have used an audio isolation transformer between BT and amp.
Good Luck
Sorry, I don't quite get your meaning by pot.
Before posing this thread, I also tried using audio transformer, it didn't do anything with the noise. This is really frustrating. 🙁
Before posing this thread, I also tried using audio transformer, it didn't do anything with the noise. This is really frustrating. 🙁
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