As an embedded tube/hybrid amplifier, the SD-DAC63115 gives you the beautiful sound of tubes together with the grunt of solid state circuitry to drive the headphones. It uses 12AU7 Tube or exact equivalents.

The 384Hz/32 bit DSD USB Audio DAC is an ultra transparent mastering grade digital audio playback system. The 384Hz/32 bit DSD DAC is capable of converting high resolution PCM audio up to 384kHz, and DSD audio(up to 128x DSD). The DAC allows you to bypass your computer's soundcard or headphone output and send digital audio signal through the USB interface. With this perfect digital interface between your computer and the music system, the sound quality is pushed to another higher level in your overall music environment.

Also built in to the system is a Tri-Tone Control Pre-Amp with built in headphone amplifier is different from many audiophile designs for its unique 3-band "Tri Tone" equalizer while most of the Hifi equipment has forgotten for many years. The Tone Control allows the audiences to master their song back to "Original" even they are playing with a lower quality MP3 files on a middle-end earphone, or they might enhance different parts of frequency range; high tones (Treble), mid-range (Middle), low frequency (Bass), in order to suit their personal taste for different kinds of music.