USB DAC and Headphone Amplifier with SPDIF


In stock

Available to ship: 1-3 business days

Choosing output op-amps

New: Use your iPhone as a digital audio source! With iOS 7, you can now use the Lightning to USB Camera Adapter to output digital audio from the iPhone 5 or 5S to the high-performance DAC in the UHA-6S.MKII. (Adapter not included.)

The UHA-6S.MKII is a high-performance USB DAC and amplifier combo. It features a 16-bit/48-kHz USB streaming interface, 24-bit/96-kHz S/PDIF (TOSLINK) inputs, and a 1/8-inch analog line input. With its low-noise, high-power output, the UHA-6S.MKII is capable of driving a wide range of headphone types, from high-sensitivity in-ear monitors to high-impedance over-the-ear headphones.

The internal Lithium-ion battery is rechargeable over USB. A charging disable feature allows the UHA-6S.MKII to be used with tablets and other devices which limit power draw.

The UHA-6S.MKII can be customized for a particular sound signature. The output stage op-amps are socketed and easily replaceable.


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.

Optical and coaxial S/PDIF digital inputs. The UHA-6S.MKII is compatible with S/PDIF sources up to 24-bit/96kHz.

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.MKII to be used as a low-noise DAC/preamp into a line input such as an A/V receiver. Additionally, there are no DC-blocking capacitors in the signal path, which can cause harmonic distortion.

Socketed op-amps. For full customization, the output stage op-amps in the UHA-6S.MKII are socketed and easily replaceable. 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 is automatically selected among the four available sources: analog, USB, optical S/PDIF, and coaxial S/PDIF.

Advanced battery management. Use any high-power USB port or USB charger accessory to charge the UHA-6S.MKII. A rear panel switch disables charging, maximizing the battery life of your portable computer or tablet PC. The front-panel power LED indicates low-battery status. A battery disconnect circuit prevents full discharge, maximizing the lifetime of the battery. The UHA-6S.MKII is compatible with most standard 5V USB wall chargers.

Plug and Play USB operation. The UHA-6S.MKII uses the standard USB audio drivers which are included in Windows and Mac operating systems.


  • Max output power (1% THD):
    • 30 mW into 16 ohms
    • 55 mW into 32 ohms
    • 110 mW into 100 ohms
    • 55 mW into 300 ohms
  • THD+N at 1 kHz (optical input, 20 Hz to 80 kHz bandwidth, no weighting):
    • 0.0035%, 1 mW into 16 ohms
    • 0.0060%, 1 mW into 32 ohms
    • 0.0022%, 1 mW into 100 ohms
    • 0.0035%, 1 mW into 300 ohms
  • Frequency response: <10 Hz to >22 kHz, +/-0.1 dB
  • Battery life:
    • >30 hours typical, analog input
    • >10 hours typical, S/PDIF input
  • Dimensions: 70 x 84 x 20 mm (2.8 x 3.3 x 0.8 inches)
  • Weight: 6.0 oz (170 g)


  • 16-bit/48kHz USB digital audio
  • 24-bit/96kHz optical and coaxial S/PDIF digital audio inputs (TOSLINK)
  • 1/8″ analog input
  • Bipolar voltage rails (+/-6 VDC) with true ground reference
  • Automatic input selection
  • Two-position gain select (+0dB/+18dB)
  • Socketed output stage op-amps (8-pin DIP, single
  • DAC: Cirrus Logic CS4398
  • DAC filter op-amps: LT6233
  • Output stage op-amps: OPA209 (other options available)
  • Uses standard USB audio drivers
  • Compatible with the Apple iPad Camera Connection Kit (CCK)
  • Compatible with Mac OS X and Microsoft Windows XP, Vista, and Windows 7
  • Rechargeable battery, charged through USB
  • Charge disable switch for maximizing battery life of laptop PCs and tablet devices
  • Power/low-battery and charge indicator LEDs
  • Available in silver or black
  • Includes Micro-USB cable and self-adhesive rubber feet