Frequently Asked Questions

Will the UHA-3 work with my headphones/earphones?

The UHA-3 is designed to drive a wide range of headphones and earphones. It can handle headphone impedances from 16 Ohms to 300 Ohms. It can also drive a high-impedance line level input (10 kOhms, for example), such as the input to a home stereo receiver.

Why not just use the headphone output on my computer/laptop?

Two reasons. First, these outputs tend to be noisy, especially with high-sensitivity headphones or earphones. The sensitive audio circuitry in the computer can pick up noise from hard drives, fans, etc. With the UHA-3, the digital-to-analog conversion is performed outside of the computer, thus eliminating these sources of interference. Second, the analog headphone amplifier circuitry in a typical computer or laptop tends to be underpowered. The UHA-3 can provide a higher-current, higher-voltage signal into a wide range of loads, resulting in a cleaner and clearer sound.

How much improvement in sound quality will the UHA-3 provide over the headphone output of my portable MP3 player?

The answer is: it depends. On some setups, the improvement is subtle. On other setups, the difference can be quite drastic. The UHA-3 provides a high-impedance load to the headphone output of your MP3 player. For the most part, your MP3 player can drive a cleaner signal to this high-impedance load than it can to a headphone load. The more difficult job of driving the headphones is left to the UHA-3. Keep in mind that the sound quality from any headphone amplifier is only as good as the source material. In other words, don't expect much improvement with low-bitrate MP3s.

Can I use the UHA-3 as a preamplifier to an A/V receiver or amplifier?

Yes. The UHA-3 can provide a 13 dBu signal into a high-impedance load, such as the line input to a receiver or amplifier. The UHA-3's USB streaming capability is a great way to provide a low-noise interface between your computer and a stereo system.

Isn't USB power too noisy to supply the sensitive audio circuitry of a headphone amplifier?

The audio circuitry in the UHA-3 does not use the USB 5V supply directly. High-frequency switching regulators provide a means of isolating sensitive circuitry from noise which might be on the USB power.

What is the dynamic range of the UHA-3?

When using the analog line input in low-gain mode, the dynamic range is greater than 120 dB A-weighted. Because the USB 1.1 audio streaming protocol is limited to 16-bit, the dynamic range when using the USB input is limited to about 96 dB A-weighted.

Which gain setting should I use?

The low-gain setting can be used in most cases, resulting in a lower output noise floor. Use the high-gain setting only if you are unable to get enough output signal level in the low-gain setting.

What sample rates are supported with USB streaming?

Sample rates of 32kHz, 44.1kHz, and 48kHz are supported. Sample rate is automatically detected by the UHA-3. Word length is 16 bits for all sample rates.

Am I required to install software/drivers on my computer to enable USB streaming?

Will USB streaming audio work with my operating system?

The USB interface chip in the UHA-3 is supported by Microsoft Windows 98SE, 98ME, 2000, XP, Mac OS 9.1 or later, and Mac OS 10.0 or later. It may be possible to use the UHA-3 with other operating systems not listed here, but compatibility is not guaranteed.

Can I use the iPod Dock Connector to USB Cable to stream digital audio from the iPod to the UHA-3?

No. The only way to stream digital audio to the UHA-3 is to connect it to a USB host, which generally means a computer. To use with an iPod, connect the headphone output of the iPod to the analog input of the UHA-3.

How long does the UHA-3 last on a battery charge?

Typical runtime is about 18 hours, but this depends somewhat on listening level and headphone impedance.

How long does it take to charge the battery?

On a typical high-power USB connection, the battery will charge from completely dead in about 3 hours.

Is it OK to only partially charge/discharge the battery?

Yes. In fact, Lithium-ion batteries tend to last longer when operated near full charge. In other words, you can leave the UHA-3 connected to USB continuously without degrading battery performance. When the battery voltage dips below a programmed threshold, the battery will automatically be recharged.

How many charge/discharge cycles will I get from the battery?