Just to be sure, why not post a schematic...
Also have you followed to find out if this helps?:
1. Pop or click when playback is started or stopped:
Ramps are built into the library to prevent popping when PWM is engaged, disabled, and between music tracks of the same
sample rate. See the [Advanced Features wiki page](https://github.com/TMRh20/TMRpcm/wiki/Advanced-Features) for causes and fixes.
Have you tried feeding the audio to a different speaker/amp?