Sony NW-A100TPS Help Manual page 103

Remove headphones from your ears before you connect them to the player. Also remove the headphones from your ears before
you disconnect them from the player. Large noise may be generated when the headphones are connected or disconnected.
You may hear noise when you turn the Noise canceling function on or off. This is not a malfunction.
The Noise canceling function is disabled while the following function is active.
Ambient sound mode
The contents of the Help Guide may be subject to change without notice due to updates to the product's specifications.
Related Topic
Switching the earbuds
Displaying Quick Settings panel
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