TPA3132D2: hear music without speaker

[FAE] Andrew Wang

Part Number: TPA3132D2

Hi Team,

An interesting thing want to share that customer reported they can hear music from PCB without connecting to speaker. Customer uses this device for many projects already, we checked every board with different layout, include our EVM, all of them can generate music from PCB directly. the power setting varied from 15W~30W.

We have tried different choke and capacitor on LC filter, and we found the sound is bigger for certain type of component some is more quieter.

So question is -> is this very common thing in class-d amp? or any type amp is possible...

Also, this is not a device specific issue?

Thanks!

Andrew

over 4 years ago

0 Sam(MPAA) Zhang over 4 years ago

TI__Mastermind 19080 points

Hi Andrew,

It's not a common thing. Are you sure it's real music but not some noise due to passive components or PCB vibration? Could you take a picture of the test setup?

Thanks!

Regards,

Sam

0 [FAE] Andrew Wang over 4 years ago in reply to Sam(MPAA) Zhang

TI__Genius 10685 points

Hi Sam,

We can hear it from our EVM as well.... you can try it, make 100% volume from source, at least 20W output power, and put your ear closed to the board around 3~5cm. I never try this closed to the board before, and we can hear music content that we played, just make sure the place is quiet.

The choke and MLCC both contribute sound, I would say 70~80% came from MLCC. This vibration sound seems able to change freq with music content so it sounds like a song, especially when you please a female vocal. If you have EVM or any other class-d board around you that can make 20W, please help me verify it, thanks.

Andrew

0 Yanming Gong over 4 years ago in reply to [FAE] Andrew Wang

TI__Mastermind 19890 points

Hi Andrew,

That's MLCC capacitors singing problem. The higher power, the singing sound more obvious.

If connected to speaker, the MLCC singing will be muffled. So no customers spend time to resolve MLCC singing problem.

Regards,

Derek

0 [FAE] Andrew Wang over 4 years ago in reply to Yanming Gong

TI__Genius 10685 points

OK!! Thanks!!

Andrew

Audio

Audio forum

TPA3132D2: hear music without speaker