Slimline USB DAC and Headphone Amplifier with Crossfeed and Digital Volume Control
Available to ship: within 1-3 business days
The UHA-4 is a USB DAC and amplifier combo featuring digital volume control, crossfeed, and a slimline case. At less than 1/2 inch thick, the UHA-4 is highly portable and fits easily into a pocket.
The digital volume control provides excellent channel balance across the entire adjustment range. The Alps control allows adjustments in 2-dB steps.
The UHA-4 crossfeed circuit works by feeding a delayed and filtered version of the sound in each channel to the opposite ear, mimicking the way we hear sounds in a natural acoustic environment. This helps to reduce the fatigue and unnaturalness produced by some headphones, especially on recordings with wide stereo separation.
The UHA-4 can drive a wide range of loads, from high-sensitivity earphones to high-impedance headphones.
Digital volume control. The digital volume circuit, actuated by an Alps up/down pushbutton control, provides extremely tight channel matching for a stable stereo image at all volume levels. The previous volume setting is restored automatically at power-up.
Crossfeed with bypass. The crossfeed circuit sends a delayed and filtered version of the sound to the opposite ear, mimicking the way we hear in a real acoustic environment. This reduces the unnatural sound of hard panning which can occur while listening to some music with headphones.
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-4 to be used as a low-noise DAC/preamp into a line input such as an A/V receiver.
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 –> USB.
Advanced battery management. Use any high-power USB port or USB charger accessory to charge the UHA-4. 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. The UHA-4 uses a commonly available iPod battery.
Plug-and-Play USB operation. The UHA-4 uses the standard USB audio drivers which are included in Windows and Mac operating systems.
- Max output power:
- 20 mW into 16 ohms
- 40 mW into 32 ohms
- 50 mW into 100 ohms
- 15 mW into 300 ohms
- THD+N, A-weighted:
- <0.025%, 1 mW into 32 ohms
- <0.025%, 1 mW into 100 ohms
- Dynamic range, A-weighted:
- 93 dB, USB input
- 102 dB, analog input, 32 ohm load
- 108 dB, analog input, 100 ohm load
- +10 dBu max into high-impedance load (>600 ohms)
- Frequency response: 13 Hz to 22.5 kHz, +0/-1 dB
- Output impedance: 0.4 ohm
- Op-amp supply rails: +/-5 VDC
- Battery life: 24 hours typical
- Enclosure: aluminum
- Dimensions: 3.3″ x 2.75″ x 0.47″
- Digital volume control
- Crossfeed (with bypass)
- Two-position gain select
- Automatic input selection
- Rechargeable battery, charged through USB
- 16-bit/48kHz USB digital audio
- DAC: Texas Instruments PCM2706
- Output driver op-amps: AD8610
- 1/8″ analog input
- Uses standard USB audio drivers, no software needed
- Compatible with Mac OS X and Microsoft Windows
- Power/low-battery and charge indicator lights
- Available in silver or black
- Includes Micro-USB cable and self-adhesive rubber feet.