There is no sound from an audio device connected to the headphone jack of the Walkman player

Depending on the connected device, there may be no sound when connecting to the Walkman® headphone jack using a cable. The headphone jack of the Walkman controls output by detecting the device connection status to reduce power consumption.

When devices other than headphones are connected, such as a car audio device, the audio may not be output because the device is not being detected as headphones, and therefore not seen as an output device. In this case, turn on the Walkman power after (not before) it has been connected to the other device.