Hi-Fi USB Audio DAC & Headphone Amplifier

Hi-Fi Audio Capabilities

With the objective of developing a product that realizes the best hi-fi sound quality, enhances user convenience, has diversified connectivity, and has most functionality relative to the price while not emphasizing on a fancy exterior and demanding specifications, the development of the HUD-mx2 has been completed after a long period of time, adopting a number of high-quality components and utilizing our company’s extraordinary PCB design technology. The HUD-mx2 is capable of processing an optical input (24bits/192㎑) and a USB input (24bits/96 ㎑) using only USB bus-power and enables users to enjoy audio playback that offers stronger sound output and higher sound quality by connecting the adaptor provided with the product. Moreover, users can enjoy audio playback from an iPad (with a camera kit) or a smartphone (with an OTG cable) that supports the new USB audio, etc. by connecting to them. Because it supports automatic power on/off and a power saving mode, the HUD-mx2 maximizes user convenience and power efficiency when using the product in the USB input mode.

Simple and Neat Overall Curve Design

Its overall smooth curve design features reverberating silver color to reflect elegant fashion,
replacing previously hardened looks often found on the front panel of DAC.
The design also eliminated any complicated words, making it look simple
and convenient for the users to operate.

Dynamic Range 123㏈

High End Performance

Our high-end audio USB DAC provides the dramatic high quality playback,
bringing out the latent possibilities of PC Audio from computer-based average
audio quality to CD-quality sound through our advanced technologies.

PCM1796 D/A converter

HiFi USB Audio

88.2㎑ Support

24/192㎑ Support

POP-NOISE Minimizing

DUAL Headphones

The Finest Quality DAC with Powerful Dual Headphone Amplifier

HUD-mx2 presents perfection-like sound quality from DAC no one has ever experienced before, with its unique circuit organization and highest quality components. This unit supports both stereo phone jack and stereo mini jack standards without requiring a separate gender converters, while its dual headphone output provides enough driving power to be used with 600Ω headphones, providing clear and high fidelity sound.

24bit/192㎑ High-Quality Sound Playback

Adopting the newest Vinyl EnvyUSB 2.0 Audio Controller from VIA, high-quality sounds with a maximum 24bits/96㎑ from a USB input and 24bits/192㎑ from the optical input can be played back with no loss of quality from the sound sources. Additionally, with the embedded PCM1796, a high-performance DAC offering a 123㏈ dynamic range from Ti, the HUD-mx2 demonstrates high-resolution sound quality and hi-fi audio quality.

88.2 ㎑ Support

88.2 ㎑ rarely supported on most of USB Audio DAC is supported in native mode. 88.2㎑ support enables a multiple up-sampling relative to 44.1㎑, which is an audio CD format.
※ Installation by being downloaded with a separate driver from website enables use of Qsound (Windows XP excepted) and AC3-Passthrough function from windows, and is supported by 24bit/88.2㎑ and the like.

Installation of TCXO

TCXO is made of an extremely thin crystal, creating peculiar vibration when applied with electricity. It is often used on resonance circuit to generate uniform frequency of electronic circuits. However, frequency error in which vibration counts of TCXO vary can arise depending on outside temperature, and such appearance can become a main reason for errors or frequency distortions on precision electrical equipments. In order to reduce frequency discrepancies due to exterior temperature, TCXO uniformly maintains interior temperature within crystal oscillator and fixates the frequency, making it an essential component for audio equipments sensitive to frequencies.

Activation of the Protection Circuit

The normal procedure to use the adaptor is make a connection to the USB port after making a connection of the adaptor, but it does not go out of order if this procedure is not followed since a protective circuit is embedded. It is normal to hear a distorted sound temporarily when you connect or disconnect the adaptor during use, since the distorted sound is a phenomena occurring when the protective circuit operates.

Mounting of Highest Level Op-amp and High-performance Headphone Amplifier

Because the I/V converter and filter circuits are designed into the DAC output terminal, strictly conforming to the standard Ti design and mounting LME49860, a highest grade op-amp from National Semiconductor and OPA2227 and OPA2134 from Ti are placed at the optimum positions to produce the best sound quality, successfully realizing the high-performance and high-fidelity audio sound with the optimum balance and very low sound distortion as well as ultra-low noise. Additionally, the mounting of TPA6120A2, a high-fidelity headphone amplifier from Ti, allows users to use headphones with impedance values under 300Ω when using it in the factory default state and enjoy sounds with enough volume from the headphones with high impedance values of 600Ω after removing the gain jumpers (JP1 and JP2) inside the main body of the product. The high-quality audio signals generated through a number of highest level components can be transmitted to a speaker, an earphone or a headphone, providing users with a hi-fi level sound environment.

LDO Regulator/Inverter circuits

To operate a high performance dual power source type OPAMP, it is required to supply positive and negative voltage at the same time. By supplying both voltages equally to the OPAMP circuit through the high performance inverter circuit after rectifying the power supplied via the USB port or an adaptor through an LDO regulator and low-ESR capacitor to obtain stable power of good quality with no noise, the rich and dense top class analog signals that can be achieved by a hi-end device can be generated.

Protective Circuit for Speakers/Headphones

HUD-mx2 incorporated protective circuit system for the speakers & headphones, preventing any potential damages by temporarily cutting-off loud signals entering the speakers & headphones during the playback, when switching Input Toggle & Off Switch.

Supports USB bus power

This product can be operated under most computing environments using USB power without connecting the adaptor. But the adaptor has to be used when using power from bus power USB hub, laptop, low power computer that have unstable power from the USB port. Make sure to use the adaptor when using an iPad or a smartphone. To use a headphone with high impedance over 150 Ω, you have to use the adaptor to obtain the maximum output.

Automatic power ON/OFF

To maximize user convenience and power efficiency, the power of this product is designed to be automatically on or off when the computer power is on or off, or when entering or releasing from the power saving mode in the case of using USB power.

Convenient Portability

Convenient Portability and Compatibility

Typical hi-fi DAC is inconvenient to carry around due to its large size, yet USB DAC has the advantage of being small and lightweight for the purpose of using it connected to the computer. As the unit gets smaller, the function of DAC reaches its limit and sacrifices with low quality audio sound. Our HUD-mx2 has overcome such limit to the maximum, developing ultra lightweight, compact DAC with reduced drop-off in audio quality. You can enjoy the music with highest quality possible audio sound wherever the computer is and, with its plug and play function.

Hook-Up Application Connecting to a smart device

HUD-mx2 also supports the connection with smart devices that support USB Audio. Finally, it also maximizes user convenience and power efficiency as it supports automatic power ON/OFF and power saving mode function when used with USB input.

※ Please refer to our website for the method of connecting to a smart device.

Front Panel

①& ② Headphone/Earphone (6.35Ø Stereo Phone Jack / 3.5Ø Stereo Mini Jack)
③ Output Toggle Switch (abbreviated as ‘Output Switch’)
④ Input Toggle & Off Switch (abbreviated as ‘Input Switch’)
⑤ Active Indicator
⑥ Volume Controller (Potentiometer)

Rear Panel

⑦ Optical IN (S/PDIF Optical Input, Pink Shutter)
⑧ Optical Out (S/PDIF Optical Output, Grey Shutter)
⑨ USB Port
⑩ Power Jack (DC Jack)
⑪ RCA Line Out

Minimum and Recommended System Specifications

• Intel dual-core CPU or better, or equivalent AMD CPU (quad-core CPU recommended)
• 2GB or more system memory (4GB or more recommended)
• Motherboard / laptop equipped with a USB2.0 or USB 3.0 port
• Install OS in a latest type HDD that offers a fast transmission speed (SSD recommended)
• Microsoft Windows 7 / 8 / 8.1 / 10 (64bit recommended)
• Amplifier and speaker or 2 channel active speaker / headphone / earphone
• Receiver amplifier with optical input (Not required. Applicable when using PCM optical output)

To fully utilize the performance of HUD-mx2’s USB audio, the specification of the system such as desktop PC or laptop has to be at a certain level. The level doesn’t have to be high necessarily but should not be too low.

Package contents

• HUD-mx2 main body
• USB cable (USB A to B Type, 1.5M)
• 4 spikes for fixing (to attach the main body to the floor)
• RCA cable (1.5M)
• Bumpon (anti-slippery, anti-vibrating rubber foot made of polyurethane
• Hexagon wrench (for attaching and detaching the volume knob)
• Power adaptor (DC 12V~15V)

※ A program/driver installation CD is not included in the product content. The above product content may be changed without notice for enhancing product functions.


Dimensions / Weight
100(mm) x 120(mm) x 29(mm) / 260g

Headphone Output
Type : 1/4” Stereo phone & 1/8” Stereo mini jack
Max Out Level : ±10Vpp@600Ω(When removing the gain Jumper)
Max Output Power : 1.5W @ 32Ω
Output Impedance : 2Ω (Load : 16Ω ~ 600Ω)

Line Output
Type : Unbalanced RCA
Level : ±3.2Vpp max
Impedance : 200Ω

USB Audio
Type : Max 24bit / 96㎑, USB 1.1 / 2.0 Compatible
OS Support : Windows 7 / 8 / 8.1/ 10, Mac OS X Compatible

Digital Audio Output
Type : S/PDIF Optical on TOS-LINK 44.1~96㎑
Format : IEC-60958, S/PDIF Compatible
Sample rate : 44.1, 48.0, 88.2, 96.0㎑

Digital Audio Input
Type : S/PDIF Optical on TOS-LINK 44.1~192㎑
Format : IEC-60958, S/PDIF Compatible
Sample rate Detection : 44.1, 48.0, 88.2, 96.0, 176.4, 192.0 ㎑

D/A Converter
Type : 24bit, High Performance 192㎑ Stereo DAC
SNR : 123㏈ (‘A’ Weighted stereo @44.1㎑)
THD+N : 0.0005% @ 44.1㎑

Operating Voltage : ±12V(with DC Adapter), ±5V(USB Bus Power)
I/V Converter : LME49860 (SMD x 2)
Differential Amplifier : OPA2227 (DIP)
Line Out : OPA2134 (DIP)
Headphone Out : TPA6120A2 (SMD)

Power Supply
DC 12V ~ 15V