NE5532: power interference

Sara,

Could you provide a circuit schematic in order to have a better approach to this issue?

Do you know if the power supplies are stable and there's no ripple or noise added in the power lines? Does this issue appear when the analog inputs are connected to GND?

Best regards,
Luis Fernando Rodríguez S.

Hi Luis,

Thanks for your reply.

the schematic is as follow：

Hi, Sara,

Thank you for providing the NE5532 schematic portion.

Do you know if the power supplies are stable and there's no ripple or noise added in the power lines?

Do the NE5532 inputs have a voltage level when the NE5532 is powered on? If the Ferrite beads FB2, FB3, FB4 and FB6 are removed, do you have the same results?

Thank you!

Best regards,
Luis Fernando Rodríguez S.

Hi Luis,

During working status, NE5532 is powered on continuously. Only switch the iaccord antecedent for XLR docking equipment.

Thanks a lot.

Hi, Sara,

In order to avoid this kind of "sounds", when an analog input is modified, it is important to verify that all the decoupling capacitors are discharged slowly and there's no a quick voltage modification.

Could you provide a scope capture of the NE5532 input voltage when the iaccord is changed for XLR docking equipment? It is just to verify how the input voltage changes at the NE5532 input.

Best regards,
Luis Fernando Rodríguez S.

Hi Luis,

the scope capture is as follow,

Pls give me some recommendation on selection to DC blocking capacitors. 

Thanks a lot.

BR

Sara 

Hi Sir,

Any update.

Thanks a lot.

BR 

Sara

Hi, Sara,

Regarding the XLR connection, is it also referenced to the same ground level than the board?

In addition, I see a 48V bias in your circuit design. Is it modified during the XLR connection? Does this value also changes?

Best regards,
Luis Fernando Rodríguez S.