Class D with built-in bluetooth?

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#21
So how noisey was it prior to the mods??

DownSouth said:
Tested with Minimus 7, AR PS2052 and Acoustech PL-980 speakers

Very easy to build.
I have the TDA7492P amp you have listed on ebay.

I also have this unit with the aux input.
50W+50W TDA7492P Bluetooth CSR4.0 Audio Receiver Digital Amplifier Board Sale - Banggood.com
The same as the one in your list but with an aux input.

I bought these for the cases. NO AUX
https://www.aliexpress.com/item/2-2...Wireless-Bluetooth-4-0-Audio/32715744656.html

https://www.aliexpress.com/item/Blu...-Board-Module-for-TDA7492P-2/32717681783.html WITH AUX

And these for the power supplies.
https://www.aliexpress.com/item/96W...-For-Laptop-Notebook-EU-Plug/32613409478.html
The company also has them with US plugs for a few cents more.
Since I've got beaucoup US plug cables I just bought the cheaper ones.

Here is an easy mod to drop the distortion and improve the frequency response. Trevor Marshall - Class D Audio Amplifier Design - TDA7498 Output filters
Click to expand...
 
#22
m0b1liz3 said:
So how noisey was it prior to the mods??
Click to expand...

It was never noisy. It had much higher distortion, especially at higher freqs.
Changing the output filter caps reduced the distortion significantly and flattened the FR at both ends.
The amp sounded better, but not cleaner which isn't surprising since double blind testing has shown that THD below 2% while playing music can't be heard by the human brain.
If the amp isn't clipping and the FR is equal amps can't be differentiated or so they say.
I still have my doubts but in MY tests driving my speakers to below clipping levels with music there was slightly better bass with my large speakers but no audible difference with the smaller ones.
There was however an audible difference using test tones at high volume AND the amp clipped differently.

I also changed out the input caps but heard no audible differences.
I later inserted a 10,000uf 35V cap at the 24V input using these which seemed to improve sustained bass notes.
https://www.aliexpress.com/item/5-p...led-lighting-accessories-for/32396704826.html

For the guy wanting background music I wouldn't bother with the mods.
I like to tinker which is why I did what I did.🙂
 
#25
Update on TDA7498P Bluetooth amp

The amps purchased at Banggood which pair as SHUNUO don't have a turn on thump.

The only physical difference I could see is the 330 caps are crosshatched on the SHUNUO board and have a solid black stripe on the edge on the SANWU board

A friend bought over a board with the AUX input which paired as SANWU and it thumps.
He bought it from Aliexpress. Looks like Banggood MAY have changed to the SANWU AUX board.
Can't post photos.

Search on TDA7492P Bluetooth at Bangood shows 3
SHUNUO TDA7492P 25W+25W Wireless Bluetooth 4.0 Audio Receiver Digital Amplifier Board Sale - Banggood.com
 
#26
DownSouth:
What rev board do you and your friend have? I wonder if it's "Shunuo" that fixed the thump or if Sanwu fixed it with a newer version and Shunuo copied the latest. The newer versions of 7492p boards I've seen on eBay seem to have an on/off switch next to the power jack, not sure why they did that. Is it main power or something else? By the way, did you notice the 2nd to last pic on that board you linked? It has the Sanwu label on the back, so who knows who makes this stuff we are buying?

Your friend might be able to fix his board with this info:
http://www.diyaudio.com/forums/class-d/290949-how-prevent-popping-sound-power-tda7492p-amp.html
 
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