Main Features

USB buss powered operation
Linear PCM audio up to 24bit/192kHz and DSD audio up to 5.6MHz playback*
Quick and easy hi-resolution playback in combination with "FOSTEX Audio Player" software
HI/LO Gain selection (10dB) for wider range of headphones

HP-A4 24bit DAC Headphone Amplifier

Model HP-A4 is a new, improved version of the acclaimed HP-A3. It offers up to DSD 5.6MHz and PCM 192kHz for superior audio playback functionality as well as the sophisticated and class-leading appearance of the flagship HP-A8C.

Fostex USB Audio Driver for Windows (V.2.2.1)
Dedicated USB driver software is necessary to install on PC for Windows. Please be sure to uninstall the old driver software, if any, before installing this new software.
You can download the Windows driver here

Windows and Mac OS Compatibility
We confirmed the compatibility with Windows XP*(SP2 or later) / Vista / 7 / 8 / 8.1 / 10 and Mac OSX(10.6 or later).
* Not compliant to XP 64bit.

Compatible with MAC OS 10.12 Sierra with Firmware update V.1.1. Click here for software downloads.

In Detail

USB buss powered operation without AC adapter
Linear PCM audio up to 24bit/192kHz and DSD audio up to 5.6MHz playback*
Quick and easy hi-resolution playback in combination with "FOSTEX Audio Player" software
HI/LO Gain selection (10dB) for wider range of headphones
Asynchronous transfer mode by using the custom made crystal
Digital Filter selecting Roll-off characteristics and Cut-off characteristics according to the audio source
Complies with USB Audio Class 2.0 on Windows XP (SP2 or later) / Vista / 7 / 8 and MacOS X 10.6 or later. **
MicroSD (SDHC) card drive on the rear panel for future firmware update.***

* requires a DSD playback software on PC such as the upcoming "FOSTEX Audio Player". Both DoP and ASIO acceptable.
** requires the dedicated driver for Windows. Not compatible with Windows XP 64bit.
*** does not playback audio data stored on a microSD card

Images

Download

Specifications

Input
USB port   sampling frequency   up to 24bit/192kHz(PCM), 5.6MHz(DSD)
   Interface   USB high speed
Digital   Connector:   optical, square
   Format   S/PDIF (16bit/24bit: 44.1 – 192kHz)

Output
Phones   Connector:   Stereo phone
   Max Output:   100mW (32-ohm loaded)
   THD:   less than 0.04% at 1kHz, 32-ohm loaded, 100mW
   Frequency response:   20Hz - 80kHz +/-3dB (1kHz, 32ohm loaded, 100mW, FS 192kHz)
Analog    Connector:   RCA Pin
   Reference output level   2Vrms
   THD:   less than 0.01% at 1kHz
   Frequency response:   20Hz - 80kHz +-3dB (at FS 192kHz)
Digital   Connector:   Optical, square
   Format   S/PDIF (16bit/24bit: 44.1 - 192kHz)

General
MicroSD card slot:   microSD card (SDHC)
   Power:   USB buss powered
   Power Consumption:   2.5W
   Accessories:   1 x USB cable (1.0m), 4 x rubber foot, manual
   Dimensions:   113mm(W) x 34mm(H) x 155mm(D)
       excluding protruded parts
   Weight:   approx. 500g