I joined all ground pins in a single row of my breadboard
Yes but that is not star wiring is it.
The whole point of star wiring is that all the ground currents do not flow through the other components. By having them all on the same row you can still have the ground currents from for example from the LEDs flowing through the audio circuits and causing what is known as ground bounce.
So can you post a proper diagram and a photograph of your setup. Both please, one on its own is not much use.