I have a little issue, I am using the Sure Electronics AA-AB41136 Bluetooth 4.0 Audio Receiver Board aptX +EDR 12 VDC as a bluetooth adapter to lead to Sure Electronics AA-AB32189 2x100W TDA7498 Class-D Amplifier Board. The problem is the input volume is so high coming into the amplifier causing the amplifier cut out at around half volume at even the lowest gain. I have tested this with out the Bluetooth board and have not and a problem with volume being too high at the output. What can I make or do to reduce input volume for the amplifier?

 

Hello,

How did you connect the two modules?
Is it like the suggested schematic in the bluetooth manual?



At what voltage do you run the powermodule?

Bertus

 

Yes it is connected to the 3.5mm output of the Bluetooth board and leads to a ground loop isolator with a stereo to mono circuit that I put inside leading to the amplifier. The Bluetooth board is running at 15 volts and the amplifier running at 36.

 

Hello,

The 3.5 mm output is for headphones only.
The ouput of that may be to high for the poweramp.
Use the RCA cables instead and see how it behaves then.

Bertus

 

It is a little better but it still cuts out at around the same volume but it is better. Can something be made to lower the input power from the Bluetooth board?

 

Hello,

Try to run the bluetooth board at 12 Volts, as that is the recommended voltage.

Bertus

 

This did not make a difference.

 

Hello,

Is the distortion also noticable with a headphone on the 3.5 mm output of the bluetooth module?
If so, the input of the bluetooth is to much.

Bertus

 

Yes it is connected to the 3.5mm output of the Bluetooth board and leads to a ground loop isolator with a stereo to mono circuit that I put inside leading to the amplifier. The Bluetooth board is running at 15 volts and the amplifier running at 36.

Why are you converting the stereo out of the bluetooth module to mono and what is this circuit? Max supply voltage on the power amp is listed at 32v by the way.
SG

 

Since there is a subwoofer on one side and tweeter and midrange I’m the other on a lot of songs parts are cut out because it is playing through the sub channel and vice versa. This seemed to fix the problem. And sorry I miss corrected, I was up late when I wrote the first post I have it at 32 volts on the amp.

 

Are you saying the volume problem is fixed now?
SG