PCM5102A: DAC producing music, but with heavy distortion – Audio forum – Audio – TI E2E support forums

Hi all, I have an AudioB I2S bluetooth audio module that i am connecting to a PCM5102A based chip and the output, while recognizable as music, is heavily distorted.

the module: https://www.tinyosshop.com/audiob-i2s-bluetooth-digital-audio-receiver-module

the PCM5102A based DAC chip: https://www.amazon.com/gp/product/B075B44CL6/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

I have the DAC connected to the audio module using BCK, DIN, and LRCK and I am able to hear musical notes but I suspect something is wrong with the DAC’s interpretation of the bit stream since there is distortion and I cannot lower the volume through the bluetooth volume controls. When the music is paused, the DAC goes quiet, but if the music volume is changed to zero, i get an intense buzzing output.

The bluetooth module’s digital output is known to be left-justified format, so I have the FMT pin brought up using the 3.3v pin supplied on the DAC. (For reference the pin-out description for FMT is: Audio format selection : I2S (Low) / Left-justified (High))

To turn off the mute,I have also brought up the XSMT pin to 3.3v using the same pin. (For reference: Soft mute control(1): Soft mute (Low) / soft un-mute (High))

For reference, the last three pins on the DAC are listed below, and I have not connected them to ground or 3.3v in any combination with success.

FLT for Filter select : Normal latency (Low) / Low latency (High)

DMP for De-emphasis control for 44.1-kHz sampling rate(1): Off (Low) / On (High)

SCL (or SCK on the PCM5102A’s pin-out) for System clock input(1), note is (1): Failsafe LVCMOS Schmitt trigger input.

I would like to have this contraption working of course, but insights on how to troubleshoot and to show the problem is the AudioB and not the PCM5102A would be good too. I have a simple oscilloscope if that should come in handy.

Thank you in advance.