TPA6120A2: analog potentiometer

Hi;
I actually placed the potentiometer there but I am having problems with the very high frequency hiss (which is only heard by young people) and I also have a very slight hum which disappears when the sound is played.

Hello Gil,

  Did this issue appear after you placed the potentiometer? I would probably also add DC blocking caps before the amp. 

Thank you,

Sima

Hi Sima, thank you for this answer,
what type of capacitors, what value, can you place them on the drawing?
thank you
Gil

Hello Gil,

  I am glad that it is fixed! That is strange I would expect the opposite since usually impedance matching would cause the problems listed. But, that is good the issue disappeared. If you would need additional filtering (especially against hum), you may place DC-blocking capacitors (very low Hz for audio), between AOP and TPA. The PCM5142 states in the datasheet that it does not require DC-blocking capacitors. The PCM5242 offers a ground centered output, so that no DC blocking capacitors are required between it and the AOP. 

  The image below shows the cap placement. However, this is not necessary since you have solved the issue.

Thank you for the update,
Sima 

Hi Simma,

Indeed I am quite surprised with the result because I have no more buzzing, no more hissing, total silence.

regards

Gil