Denon DA-300USB DAC Headphone Amplifier & AH-D600 Music Maniac Headphones Bundle The Denon DA-300USB is a high quality headphone amplifier that connects to your PC or Mac via a USB cable. The DA-300USB is equipped with dual master clock crystals, for compatibility with the widest range of sampling frequencies (44.1kHz and 48kHz). In addition to decoding traditional PCM digital audio, the DA-300USB also provides DSD decoding (Direct Stream Digital - the high resolution audio format of SACD). The Denon AH-D600 Headphones have pentagonal shaped memory foam ear pads and an adjustable headband for superior comfort and a great fit. The AH-D600 Headphones have 50mm of free edge nano fiber driver that provide the performance of a box loudspeaker from a headphone.