Skoda BLUES Owner's Manual page 11

Caution
The AUX-IN socket must only be used for audio sources!
Note
Your radio has no control over the level setting of the external source. Make sure
that the highest quality is achieved by a suitable combination of input sensitivity
and output sensitivity of the external source (volume control). You will find detailed
information for this setting in the operating instructions of the units.
If an external audio source is connected via AUX-IN, which is equipped with an
adapter for external power supply, it can occur that the audio signal is interrupted.
This depends on the quality of the adapter which is used.
The loudspeakers in the vehicle are matched to a power output of the radio of
30°W.
CD player 9