TPA3116 + CSR8635 Idle Noise

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Hello I've recently bought on Aliexpress class D amp TPA3116 + CSR8635. What is important to me it has potentiometer and 50W per channel. Nice feature is connecting DC with screws.

Annyway, I have an issue with noise, when bluetooth device is not connected. probably noise also exists when music is playing. But when music is being switched off - noise is very laud. Off course I could turn the potentiometer down - but it is not a acceptable solution here :( I used 24V 4.2A DC as power source. tested with one speaker connected.

I'm attaching photo of the board. Maybe someone will help me to solve noise issue ?

An externally hosted image should be here but it was not working when we last tested it.
 
Hello, I tested this module with 12V battery as power source. Noise is still present just from the beginning. I've also tested different power sources - laptop's dc adapters - same result. The noise will be louder if I change gain with potentiometer.
There is any chance to fix this issue ?
 
Hello, I tested this module with 12V battery as power source. Noise is still present just from the beginning. I've also tested different power sources - laptop's dc adapters - same result. The noise will be louder if I change gain with potentiometer.
There is any chance to fix this issue ?

Does the pot have writing on the back? Like "B50K" or similar?
 
yeah...
welcome to the world of ultra cheap amplifiers , the thing is that I doubt anybody makes these cheap modules for the purpose of selling to the diy market, they are all destined for a retail product of some sort, that means that the modules you get maybe genuinely surplus and perfectly fine, or they may just not pass quality standards, so as the product manager you suddenly have the choice, do you put them in the bin or on ebay/allie?
So here we are, now the fix maybe simple but you have to decide for yourself how much time and money, well mainly time, you are prepared to spend on a ~$10 board for what could be indeed a simple component fix, but could just as well be a fundamental design flaw.
FWIW I have a number of these tpa3*** modules with soldered on bluetooth board, and they are all unusable, now I can't say that the next one you get will also be bad, but your experience here and now just confirms my bias.
 
Most likely not. I'll need high resolution pictures of front/back side of the board. (Sharp, without flash marks, straight)

One more thing to try, solder a big LowESR Cap in parallel with the yellow tantal cap right above the relay. Please note, die brown indicator on there is +++ while on Elytcaps the --- is marked. something like 1500-2000uF is a good start.

Patching the board for fully-differential most likely kills the aux-functionality.
 
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