I bought a doukaudio/nobsound tpa 3116 amp bluetooth board which is more expensive than other boards but seems to have better components etc. For a boombox project. However the bt connection has static which seems to be a ground loop problem common in bt receivers. Has anyone had a similar problem or is mine defective?
Bump!
No one has tried these amps with bluetooth modules?
And the other problem that now appeared is the following. I bought some 12v li-ion battery modules to use in the boombox project. The issue is that it seems their protection circuit trips when connected to the PS caps of the amp. I guess it is battery overcurrent protection? If I mute unmute the amp a couple of times sometimes the battery starts up and works. However this is not what I expected and I have never seen anything on the net about this problem.
So rip out the protection circuit ? Or put smaller caps on the amp?
Oh and I tried to connect the 12v batteries in series to get 24V but again one of the batteries trips in this configuration.
No one has tried these amps with bluetooth modules?
And the other problem that now appeared is the following. I bought some 12v li-ion battery modules to use in the boombox project. The issue is that it seems their protection circuit trips when connected to the PS caps of the amp. I guess it is battery overcurrent protection? If I mute unmute the amp a couple of times sometimes the battery starts up and works. However this is not what I expected and I have never seen anything on the net about this problem.
So rip out the protection circuit ? Or put smaller caps on the amp?
Oh and I tried to connect the 12v batteries in series to get 24V but again one of the batteries trips in this configuration.
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doctormord:
I see you on your site you have a fix for "noise" for the sanwu tpa 3116 amp where you disconnect the bluetooth buffer. Is this the problem here too? The noise you mention is the bt static? Why would the buffer be a problem. Is it a grounding issue?
I see you on your site you have a fix for "noise" for the sanwu tpa 3116 amp where you disconnect the bluetooth buffer. Is this the problem here too? The noise you mention is the bt static? Why would the buffer be a problem. Is it a grounding issue?
The fix doctormod described is for Sanwu boards where there is a single ended buffer between the differential outputs of the BT chip and the differential inputs of TPA3116. Removing the the buffer from the path and wiring differential outputs of the BT chip directly to the differential inputs of TPA3116 eliminates the noise. (I am highly curious as to why they put that buffer on the board in the first place. Probably somebody copied the schematics of a TPA3116 board with AUX input and added the BT output signals to where the AUX input was in the original design.)
In your case, this is probably not very practical. The 2.1 amp you are using has tone control and low pass filter stages which probably use opamps. I'm not sure how you can bypass all that stuff cleanly.
In your case, this is probably not very practical. The 2.1 amp you are using has tone control and low pass filter stages which probably use opamps. I'm not sure how you can bypass all that stuff cleanly.
I haven't heard any any chinese amp-board with tone-control which did not suffered from noise problems.
Is the noise gone if you're using the AUX?
Things might get better if you put some 10R in the supply line of the BT module and solder a good low ESR filtercap across the supply input.
From here:
https://image1.pushauction.com/0/0/...9f8e/7343016f-0791-4eab-b38c-4f378fd3db62.jpg
It's pin 1-2. It needs to "low esr" and "huge" in terms of capacitance. I had success on other modules with 10R+1500uF.
It is a pretty common issue with these modules and yours in general.
Is the noise gone if you're using the AUX?
Things might get better if you put some 10R in the supply line of the BT module and solder a good low ESR filtercap across the supply input.
From here:
https://image1.pushauction.com/0/0/...9f8e/7343016f-0791-4eab-b38c-4f378fd3db62.jpg
It's pin 1-2. It needs to "low esr" and "huge" in terms of capacitance. I had success on other modules with 10R+1500uF.
It is a pretty common issue with these modules and yours in general.
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