So after a couple days of waiting for parts to arrive, I finally put everything together and it works! But there's a small problem, The tweeter, and the woofer started to make a small hissing noise. The hissing starts to get louder when I connect the Bluetooth module to it. How can I fix this ? thanks all
LOL. Hissing is not a speaker problem. It is noise generated by your amplifier. This implies that you have the volume cranked up. Class-D amps have a reputation for similar noise issues. Likewise, the Bluetooth receiver generates noise. More expensive electronics MAY be better, and maybe not. You may have a gain structure issue. That's where your amplifier system unnecessarily attenuates the signal and then amplifies it back up again, bringing up the noise with it. That's why the volume control should be as late in the system as possible. It's a balance between noise and clipping at each stage.
Perhaps some photos showing how you have set up the system may help us suggest a solution?
Thanks for the photos.
How are you controlling the volume?
Perhaps steveu will come back and share his expertise further.
How are you controlling the volume?
Perhaps steveu will come back and share his expertise further.
The volume was control by the Bluetooth module (qcc3031) and based ổn the datasheet, the module use tpa6132a2 as its own amplifier
I've not worked with Bluetooth, so I'm putting up the specs of your modules for the experts. Perhaps they will guide you.
The TPA 6132A2 is a 25 mW, stereo, analog input headphone amplifier.
https://www.ti.com/product/TPA6132A2
The QCC3031 a flash programmable Bluetooth module.
https://www.qualcomm.com/products/application/audio/qcc30xx-series/qcc3031
The TPA 6132A2 is a 25 mW, stereo, analog input headphone amplifier.
https://www.ti.com/product/TPA6132A2
The QCC3031 a flash programmable Bluetooth module.
https://www.qualcomm.com/products/application/audio/qcc30xx-series/qcc3031
I've picked up a fragment of information that the QCC module may be troubled by noise issues if the amplifier is too close to the module.
Try placing the two boards much further apart.
Also, using a 0.025 W headphone amplifier to power loudspeakers will probably require you to max out the volume, thus emphasising the hiss.
Try placing the two boards much further apart.
Also, using a 0.025 W headphone amplifier to power loudspeakers will probably require you to max out the volume, thus emphasising the hiss.
Thanks you for the suggestions, but it still not explain why the hissing its still there even when the qcc its not connect. But this the hissing its much smaller.
so after scouting around the internet, I found 2 solutions.
1. The problem here is the power supply, I need to add a capacitor to the power input of the pam8610
2. The problem here is the output, the output has to connect to a pair of transformers,coil or capacitors and then add the speaker in series.
Will these solutions help? Thanks all
1. The problem here is the power supply, I need to add a capacitor to the power input of the pam8610
2. The problem here is the output, the output has to connect to a pair of transformers,coil or capacitors and then add the speaker in series.
Will these solutions help? Thanks all
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I'm confused - you did not mention a PAM 8610 amplifier module earlier - you mentioned a TPA 6132A2.
The 10 W per channel Class D PAM 8610 requires its own dedicated 12V DC power supply.
According to the connection diagram I have seen, you can connect your current speaker setup directly to this amplifier's output terminals.
i read that the amp is set to maximum gain, which may explain your hiss problem.
The 10 W per channel Class D PAM 8610 requires its own dedicated 12V DC power supply.
According to the connection diagram I have seen, you can connect your current speaker setup directly to this amplifier's output terminals.
i read that the amp is set to maximum gain, which may explain your hiss problem.
I think I understand better now.
Were you saying that that the bluetooth module incorporates its own TPA 6132A amplifier?
In that case, you may have too much gain (amplification).
Can you bypass the Bluetooth's internal amplifier stage?
As I said earlier, I have no exerience with Bluetooth modules.
Were you saying that that the bluetooth module incorporates its own TPA 6132A amplifier?
In that case, you may have too much gain (amplification).
Can you bypass the Bluetooth's internal amplifier stage?
As I said earlier, I have no exerience with Bluetooth modules.
As steveu said back in post #55, you may have a gain structure issue.
Can you adjust the gain of each of the modules to minimise the hiss?
Can you adjust the gain of each of the modules to minimise the hiss?
Reducing the gain with the qcc software was not helping at all, but I found this video on yt might be able to help me solve my problem. But due to the lack of knowledge in this area, I still need the experts to confirm if this will work. Thanks
The video : YT
My measurement :
when the BT module is connected :
When the BT module is not :
The audio was more audible when the bluetooth module is connected
The video : YT
My measurement :
when the BT module is connected :
When the BT module is not :
The audio was more audible when the bluetooth module is connected