USB DAC and Headphone Amplifier
with S/PDIF Optical Input
The UHA-6S is a high-performance USB DAC and amplifier combo. It features a 16-bit/48kHz USB streaming interface, a 24-bit/96kHz optical S/PDIF (TOSLINK) input, and a 1/8-inch analog line input. With its low-noise and low-distortion performance, the UHA-6S can drive a wide range of loads, from high-sensitivity earphones to high-impedance headphones.
The all-aluminum construction of the UHA-6S provides a solid yet lightweight feel. The internal Lithium-ion battery is rechargeable through the USB connection and provides up to 35 hours of operation. A rear panel switch disables the charging function, maximizing the battery life of your portable computer or tablet PC and allowing the UHA-6S to function on a low-power USB port.
The UHA-6S can be customized for a particular sound signature. All op-amps in the design are socketed and easily replaceable. With bipolar +/-6V voltage rails and automatic DC offset removal, the UHA-6S is compatible with a wide range of op-amps.
High-performance Cirrus Logic DAC. The CS4398, Cirrus Logic’s flagship digital-to-analog converter, is a long-time favorite of audio enthusiasts due to its exceptional performance and audio quality.
True ground audio reference. With bipolar voltage rails at +/-6 VDC, there is no need for an output ground buffer which can cause additional output distortion and other audio artifacts. This also allows the UHA-6S to be used as a low-noise DAC/preamp into a line input such as an A/V receiver.
Socketed op-amps. For full customization, all op-amps in the UHA-6S are socketed and easily replaceable, including the DAC filter and the output driver stage. Single-channel op-amps are used throughout for minimal channel crosstalk.
Two-position gain control. Optimize performance for your headphones or earphones by choosing from two gain settings.
Automatic input selection. The input source is automatically selected based on the following priority: analog –> optical –> USB.
Advanced battery management. Use any high-power USB port or USB charger accessory to charge the UHA-6S. A rear panel switch disables charging, maximizing the battery life of your portable computer or tablet PC. The power indicator turns red when the battery is low, and an internal circuit disconnects the battery before discharging completely, maximizing the lifetime of the battery.
Plug and Play USB operation. The UHA-6S uses the standard USB audio drivers which are included in Windows and Mac operating systems.
- Max output power:
- 25 mW into 16 ohms
- 50 mW into 32 ohms
- 75 mW into 100 ohms
- 35 mW into 300 ohms
- THD+N at 1 kHz (20 Hz to 80 kHz bandwidth, no weighting):
- 0.006%, 1 mW into 16 ohms
- 0.005%, 1 mW into 32 ohms
- 0.004%, 1 mW into 100 ohms
- 0.003%, 1 mW into 300 ohms
- Dynamic range, A-weighted:
- 96 dB typical, USB input
- 110 dB typical, optical input
- >120 dB typical, analog input
- 14 dBu max into high-impedance load (>600 ohms)
- Frequency response: 3 Hz to 23 kHz, +0/-1 dB (48 kHz sampling rate)
- Output impedance: 0.4 ohm
- Op-amp supply rails: +/-6 VDC
- Battery life:
- up to 35 hours, analog input
- up to 15 hours, optical input
- Enclosure: aluminum
- Dimensions: 4.0″ x 2.1″ x 0.9″
- 16-bit/48kHz USB digital audio
- 24-bit/96kHz optical digital audio (TOSLINK)
- 1/8″ analog input
- Bipolar voltage rails (+/-6 VDC) with true ground reference
- Automatic input selection
- Two-position gain select (+6dB/+18dB)
- Socketed op-amps (8-pin DIP, single)
- DAC: Cirrus Logic CS4398
- DAC filter op-amps: LT6233
- Output driver op-amps: AD8610
- Uses standard USB audio drivers
- Compatible with Mac OS X and Microsoft Windows XP, Vista, and Windows 7
- Rechargeable battery, charged through USB
- Charge disable switch for maximizing portable computer battery life
- Power/low-battery and charge indicator lights
- Available in silver or black
- Includes Micro-USB cable and self-adhesive rubber feet
http://www.hifi-forum.de/viewthread-211-300.html (German language)
UHA-6S User Guide (pdf, 569 kB)
2HD = Second Harmonic Distortion
3HD = Third Harmonic Distortion
Measurement Bandwidth: DC to 80 kHz, no weighting