The ASUS Adap Bluetooth USB-BT540 (Transmitter & Receiver) is a Bluetooth 5.4 audio adapter that functions as a transmitter and receiver and is compatible with Windows 10 and 11. It supports the connection of up to 7 Bluetooth devices simultaneously and offers stable, energy-efficient transmission with the LC3 codec.

The Sennheiser Momentum headphones are Bluetooth audio devices that are generally compatible with Bluetooth adapters as long as the Bluetooth versions and profiles match. As the ASUS USB-BT540 supports Bluetooth 5.4, it is backwards compatible with older Bluetooth versions as used in the Sennheiser Momentum headphones.

However, it should be noted that the Denon DCD-F107DAB tuner/amplifier with USB port does not usually function as a Bluetooth host, but the USB port is usually intended for USB memory or computer connection. The ASUS USB-BT540 is primarily intended for use on computers with Windows 10/11 to extend Bluetooth functionality.

Therefore, there is no direct connection between the Denon device via USB and the ASUS Bluetooth adapter. In order to use the Sennheiser Momentum headphones wirelessly with the Denon tuner/amplifier, a Bluetooth transmitter would be required, which is connected to the audio output of the Denon.

To summarise: The ASUS USB-BT540 is compatible with the Sennheiser Momentum headphones when used with a Windows PC. However, direct use with the Denon DCD-F107DAB via its USB port is not possible.