USB DAC and Headphone Amplifier with TOSLINK Optical and Digital Coax Inputs


In stock

Available to ship:
1 to 3 days

Choosing output op-amps

AD8610 vs AD8620

  • Functions as a high-performance DAC/amplifier combo or amplifier only
  • Provides a low-noise and transparent listening experience
  • Accepts USB digital audio up to 16-bit/48-kHz
  • Accepts optical (Toslink) and digital coax up to 24-bit/96-kHz
  • Supports digital interface to iPhone 4s/5/5s/5c and iPod Touch 5th generation (requires iOS 7 and Lightning to USB Camera Adapter or Camera Connection Kit)
  • Supports digital interface to all iPad models (requires Lightning to USB Camera Adapter or Camera Connection Kit)
  • Supports digital interface to Android devices (requires standard USB audio class support)
  • Works with practically any type of headphone, from sensitive IEM to high-impedance over-the-ear
  • Includes rechargeable battery, charges over USB
  • Includes charge disable switch for battery-only operation
  • Includes socketed op-amps for sound signature customization

"Our number one recommendation for low cost portable headphone amps."

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.

The UHA-6S.MKII has been selected by InnerFidelity for their headphone amplifier "Wall of Fame".

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.

(Typical performance, AD8610 op-amp)

  • Max output power (<1% THD):
    • 25 mW into 16 ohms
    • 55 mW into 32 ohms
    • 90 mW into 62 ohms
    • 90 mW into 100 ohms
    • 40 mW into 300 ohms
  • THD+N at 1 kHz (analog input, 20 Hz to 20 kHz bandwidth, no weighting):
    • 16 ohms
      • 1 mW: 0.0033%
      • 10 mW: 0.0045%
    • 32 ohms
      • 1 mW: 0.0018%
      • 10 mW: 0.0022%
    • 62 ohms
      • 1 mW: 0.0012%
      • 10 mW: 0.0014%
      • 50 mW: 0.022%
    • 100 ohms
      • 1 mW: 0.0010%
      • 10 mW: 0.0011%
      • 50 mW: 0.012%
    • 300 ohms
      • 1 mW: 0.0008%
      • 10 mW: 0.0023%
  • Frequency response: <10 Hz to >22 kHz, +/-0.1 dB
  • Battery life:
    • >30 hours typical, analog input
    • >10 hours typical, S/PDIF input
  • Output impedance: <0.5 ohm
  • 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: AD8610 (other options available)
  • Uses standard USB audio drivers
  • Compatible with some Apple devices using the Lightning to USB Camera Adapter (or the Camera Connection Kit for iPads with 30-pin interface)
  • Compatible with some Android phones
  • Compatible with Mac OS X and Microsoft Windows XP, Vista, Windows 7, Windows 8
  • 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