SANWU TPA3116 + CSR8635 Bluetooth 4.0 - Noise Fix

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noise

hi,i'm new to this forum and idk if is the right place to post this here.
i have bought a 2x3w pam8403 bluetooth amplifier
the amp is very loud and when i play it at low volume has a hiss noise



can i do somthing to it? to not hear the noise as is verry annoying




71QeFARGuBL._SL1024_.jpg
 
Hi everybody ! First of all, thank you for all the interesting answers and research about this pretty useful board !
My problem : I would like to select the input with a switch. Indeed, the module automatically switch from Bluetooth to Aux when you connect an Aux jack wire to the board. Nevertheless, I would like to keep the Aux wire in, and switch between Aux and BT manually, thanks to a manual switch.
1) My first option : I guess (hope) that there is an option to flash the CSR module and change the JACK_DETECTION parameter in order not to automatically select the Aux connection when a jack input is detected. In that way, I will be able to keep the Aux jack connected all the time. Nevertheless I will have to plug the manual switch but I don't know exactly where ...
2) My second option : Plug the Aux Input to the manual switch, and plug it between the CSR module and the TDA7492 amp, to select the input, but I don't know exactly where : just after the CSR module ? After the NE5532 pre-amp ? Before the TDA7492 amp ?

Thank you for your good advices ;)
 
Hi everybody ! First of all, thank you for all the interesting answers and research about this pretty useful board !
My problem : I would like to select the input with a switch. Indeed, the module automatically switch from Bluetooth to Aux when you connect an Aux jack wire to the board. Nevertheless, I would like to keep the Aux wire in, and switch between Aux and BT manually, thanks to a manual switch.
1) My first option : I guess (hope) that there is an option to flash the CSR module and change the JACK_DETECTION parameter in order not to automatically select the Aux connection when a jack input is detected. In that way, I will be able to keep the Aux jack connected all the time. Nevertheless I will have to plug the manual switch but I don't know exactly where ...
2) My second option : Plug the Aux Input to the manual switch, and plug it between the CSR module and the TDA7492 amp, to select the input, but I don't know exactly where : just after the CSR module ? After the NE5532 pre-amp ? Before the TDA7492 amp ?

Thank you for your good advices ;)

Look here. Hope it helps. I could fix my problem. :)
 
Look here. Hope it helps. I could fix my problem. :)

Thanks for your advice, I discovered this thread last week, which is very interesting and I will definitely do this mod ! Nevertheless, I don't know how to switch from AUX to BT and BT to AUX manually ...

I was thinking to flash the CSR BT module in order to affect a PIO pin to the analog pin of an Arduino Nano, which will be monitoring the manual switch and affect the CSR PIO pin to switch the input ... I don't know if it will work like this :rolleyes:

Let me know if it is not totally clear for you ;)
 
Look here. Hope it helps. I could fix my problem. :)

Thanks for your advice, I discovered this thread last week, which is very interesting and I will definitely do this mod ! Nevertheless, I don't know how to switch from AUX to BT and BT to AUX manually ...

I was thinking to flash the CSR BT module in order to affect a PIO pin to the analog pin of an Arduino Nano, which will be monitoring the manual switch and affect the CSR PIO pin to switch the input ... I don't know if it will work like this :rolleyes:

Let me know if it is not totally clear for you ;)
 
Hi there,
i bought a similar Amplifier, with similar problems.
It has that hissing noise, even when connecting the differential Output directly.
Also i think the gain is way too high, as the Bluetooth beep boop sound is earwreckingly loud.


It has 75k an 47k on the gain voltage devider.


I would like to replace the 75k resistor with a potentiometer, what kind of potentiometer would you use for that?


Do i have to replace the 47k resistor as well for that?


Sorry my electronics is a bit rusty, i'm more of a software person.
 
i changed the resistors so its on 32 db not 36 which makes it a bit better, but i still have a hisssing sound which comes on a short while after the circuit is starting. when pausing the music and starting it again there is no hissing, but after a while there is a slight hiss.
I wasnt able to remove the differential to non differential chip as that drives the muting circuit of the Amplifier and removal causes the amplifier to switch on and off all the time.
 
CSRA64215 + TPA3118 board

Thank you for these easy and useful mods! I have a CSRA64215 + TPA3118 board, since the modifications are the same, I post my results in this thread.

I did these modifications: Remove the preamp, antenna mod (post #111), reduce the gain (20 kΩ resistor → 5,6 kΩ), bootstrap snubber. They work great and reduce the noise drastically!
CSRA64215 + TPA3118 board.jpg


The Inductors get very hot (at very low music level: 65 °C!) so I compared 24 V and 12 V power supply: 24V: 145 mA →3,5 W, 12V: 83 mA →1,0 W! So I recommend using a 12 V power supply or upgrading the inductors.

I got rid of the start up pop by modifying the CSR-module: System → Timers: Audio Amplifier Unmute Time: 200 ms

I also did some oscilloscope measurements:
CSRA64215 + TPA3118 _Noise.jpg
CSRA64215 + TPA3118 _sine wave.jpg
 
big problem for the noise on this combination is probably not regulated power supply for the NE5532. It is only filtered, but I will suggest to put some regulator like 7812, or LM317 (as 12V) on pin 8.
Avoiding NE5532 you loose some dB, cause NE5532 is low pass filter and balanced to unbalanced converter.
When you put output from bluetooth module directly to the balanced input of the amp maybe you put the noise into the amplifier.
 
Hello Pitbul, I did some tests:

I removed the audio line between the CSRA and the TPA and shorted the TPA inputs (INPR to INNR and INPL to INNL): Still 148 mA while playing music and (like before) 15 mA without music. This made me wonder because the CSR can not consume that much power. Next I analyzed the TPA mute pin. Tadaa: If no music is transmitted the mute pin is high (3,3V), muting the amplifier. If music is transmitted (even at zero volume) the CSRA chip pulls the mute pin to GND, unmuting the amplifier →high current draw.

Because of the shorted differential Inputs, I think that there is no problem with high frequency jammed audio input signal. Do you have any other ideas?
 
any mods to stop the BT chip resetting with too much volume? its annoying me this one as i have one that works perfectly, but 6 that dont.

one is a SANWU-HF69B-6W+6W

and the others are

CSR8645 Bluetooth V4.0 Amplifier Board Module APTX 2*5W
 

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