The Glacier
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glacier
[/ˈglāSHər/]
–noun
an extended mass of ice formed from snow falling and accumulatingover the years
and moving very slowly, either descending from highmountains, as in valley glaciers,
or moving outward from centers ofaccumulation, as in continental glaciers.
The Apex Glacier is our take on a small portable headphone amplifier/DAC.
Features:
24-bit, 96-kBPS USB DAC – A Cirrus Logic DAC driven by a Tenor isochronous USB interface provides support for up to 24-bit, 96-kSPS digital audio from a USB host. This implementation requires no drivers, and works seamlessly with Windows or Mac PCs or other devices with a USB host port (including the iPad using the Apple CCK). Charging from the USB DAC port can be enabled or disabled, to allow use with low-power portable devices that cannot supply enough current to charge the Glacier.
Stepped Attenuator - No cheap volume control pot here. Small potentiometers are notoriously bad - they mis-track, get noisy, and break. So the Glacier uses a microprocessor-controlled analog stepped attenuator. Each of the 32 steps changes the volume level by a precise 2dB, and the gain difference between channels is less than ±0.2dB - compare that to normal pots that at best provide ±3dB! The current volume setting is indicated by the color of the front-panel LED. In addition, you can select 0dB, 10dB, or 20dB of maximum gain at the press of a button, to accommodate all sources and headphone sensitivities
High output power - What's the point of a headphone amp if it can't drive any more than your iPod? Using a current feedback amplifier, the Glacier puts out 2.6V RMS (7.4V P-P) and up to 100mA of output current, so can easily drive nearly any headphones. The highly efficient, high frequency regulated power supply guarantees full output power over the life of the battery, with low noise and high output current for powerful bass response, even with low impedance headphones.
DC-coupled design - The signal path in most portable amps is AC-coupled, with a single power supply. This requires the audio signal to pass through multiple capacitors, which degrade the sound and limit frequency response. The Apex Glacier has a bipolar power supply, allowing the audio path to be DC-coupled. That means the low-frequency response extends to 0Hz!
Long-lasting, rechargeable battery - The Glacier contains a lithium-polymer battery which will power the amp for 12-15 hours at typical listening levels. It recharges in about 2 hours from any USB port, or a USB wall charger. You can also operate it while plugged in to keep the battery topped off.
Slim, stainless-steel case – A full metal enclosure with stainless-steel skins makes the Glacier slim, strong, and resistant to EMI (electromagnetic interference). Sized to match common portable devices, the Glacier is the thinnest portable headphone amp made!
Click on the photos for a full resolution version
A review from our friend Chris Martens..
A review from Headphonia
...and Audio-Head
Measurements and Specifications
NOTE: Please read the page about headphone & amp specs!
Values are typical. Measured running from the interbnal battery.
Frequency response: DC to >100kHz, ±1dB; 20Hz - 20kHz ±0.1dB @ 1V out
Maximum output: >2.6V RMS into 150Ω; >1.7V RMS into 32Ω
Output source impedance: Approximately 2Ω
THD+N: 0.005% @ 1V RMS out, 20Hz - 20kHz into 150Ω
Broadband noise: <10μV RMS, unweighted, integrated over 20Hz - 20kHz
Output DC offset: <5mV
Input impedance: 10kΩ
Maximum input level: 2V RMS
Channel tracking (gain difference between channels, all volume steps): <±0.2dB
Maximum gain: 0dB, 10dB, or 20dB, ±<0.5dB
Dimensions: 114mm long x 65mm wide x 9mm thick
FFT: (1V RMS @ 1kHz into 33 ohms and 150 ohms):
Frequency response (1V into 33 ohms and 150 ohms):
THD+N vs. frequency (1V into 33 ohms and 150 ohms):
THD+N vs. input voltage (20dB gain, so output = 10x input) (1kHz into 33 ohms and 150 ohms):