The A&K players are not designed for Bluetooth headphones.
A&K recommend to use cable headphones/in-earphones.
Please note information below.
Bluetooth Support Specifications
l Profile: A2DP, aptx HD
l Device performance may be affected during Hi-Fi playback. (48 kHz or lower is recommended.)
Do not turn off the device while connected to Bluetooth.
Power cycle the Bluetooth device in case of malfunction.
Pairing methods may differ for each individual Bluetooth device.
Always refer to the respective instruction manual for details.
When connecting the product to a Bluetooth device, the distance between the two must be within 20 cm.
Audio quality will degrade with longer distances, and the pairing may disconnect at a distance of 2 m (6.5 ft) or more. (Distances may vary depending on device and environment.)
Crosstalk may be heard while using Bluetooth.
For multipoint devices, make the necessary connections prior to use.
Car audio Bluetooth connections are not supported.
Malfunction, noise, and other undesirable effects may occur due to the device's battery level and the environment.
l If signal interference affects data transmission. (e.g. holding the device while wearing a Bluetooth device, holding the device while holding another electronic device, etc.)
l If the device or Bluetooth headset's radio transmitters are touching parts of the body.
l If the transmission strength is affected by walls, corners, partitions, etc. If device using the same frequencies cause interference. (e.g. medical devices, microwave ovens, Wi-Fi, etc.)
l Areas with an excessive amount of interference or weak signals. (e.g. elevators, underground, etc.)