During the research of USB dongle project, we devoted to realize what is not fulfilled by products on the market. It is obvious no matter what is claimed they are all weak in output driver, limited by form factor and USB bus supply. Phatlab is determined to tackle the limits. Luckily, prior experience with RASA, a powerful desktop amplifier, has led us to experiment with same device on new topology. The achievement is worth all the efforts. Though the final rated power is subject to up limit of power supply, RIO delivers the same level of dynamics and transients as a desktop amplifier on the configuration. Features Description Specification Package Content -   Balanced output built with desktop level amplifiers -   2nd USB-C connector for enhanced power supply and output power -   Large polymer capacitors for best transient and slam response -   Current feedback amplifier with widest bandwidth and least phase distortion -   Plays all 32bit/384kHz formats: PCM, DoP, DSD64, DSD128 and MQA -   Supports playback from iPhones, Android smartphones, Game console, MacOS and Windows computers -   Friendly physical volume control buttons -   Convenient Line-out mode as pure DAC source -   Elegant and stylish enclosure is made of solid aluminum with precise CNC milling and highest quality Enhanced power supply and smart switch Power supply is always the weakest link in USB dongles for it drains the precious power from skinny mobile devices. Not only the scenario confine the output capability of amplifier, it also shorten the running hour of mobile devices, certainly lose-lose situation. A simple but smart move by adding another USB-C receptacle dedicated to external power supply tackles the dilemma of USB dongle. Behind the extra power jack, it takes engineering wisdom to auto switch between alternative supplies without blackout on USB connectivity or music playback.Polymer capacitors and resistors dedicated to audio quality A large capacitor with lowest impedance across wide bandwidth is key to quality of power supply. In RIO, high capacity conductive polymer tantalum capacitors are adopted at USB injection and supplies of power amplifier ensuring in-time response to most dynamic music passage. USB dongles always adopt smallest parts fitting in minimal dimension. It is fine for a digital USB disk but definitely worsen the audio performance. Rising temperature is a big enemy to analog circuitry, it leads to instability and inferior operation. One size smaller resistor has only 1/4 power rating than bigger one. It means the smaller resistor runs hotter sooner and generate more noise. That is why we choose big resistor whenever possible. The performance of RIO is highly assured on circuit stability and quality of power supply.Physical volume control It is often exercised to streamline a USB dongle in every aspects from dimension to control interface. However, it is counterintuitive in operation or worse, deterioration in sound quality. RIO is equipped with physical volume control interface and fix host device at maximum volume. By this configuration, we can avoid the digital volume control of host device and maintain best S/N ratio through 32-bit volume control in DAC. Volume level is easily identified through a single LED from red, green, blue, up to white related to color spectrum low (volume) to high (volume). A line-out mode uses RIO as pure DAC source is hassle-free by holding Vol+ button while plug into host.Stylish enclosure with prestigious quality The enclosure of RIO is designed with elegant style while fulfilling functionality well. It is milled from a solid mass of aluminum with highest rigidity and robustness.  Upon the solid core the finish is carefully sanded, polished and ionized to highest standard. Though there are stylish edges and curves, users can feel smooth and handy. It is well recognized the chassis of audio equipment is foundation of performance. Phatlab keep the belief in a small USB dongle too. The RIO is a beloved master piece in hands and has the most solid construction supporting top-notched electronics.MQA embedded RIO includes MQA Renderer technology, which can connect to an MQA Core signal and complete the final unfold of an MQA file. The RIO LED glows magenta to indicate that the unit is rendering an MQA stream or file. This delivers the final unfold of the MQA file. Input 1st USB C (device) 2nd USB C (5V power only) Output power (4.4φ) 2.0 Vrms Output power (3.5φ) 1.0 Vrms Headphone impedance 16 - 600 ohm Audio formats PCM: up to 384 kHz MQA renderer: up to 384 kHz DSD: 64/128 DoP Power supply 5V/1A Dimensions (WxHxL) 85 x 15.2 x 32.5  mm Net weight 57 gram 1 x Phatlab Rio1 x USB-C OTG Cable1x Instruction Manual
