NuForce icon uDAC-2 User manual

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uDAC-2

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FC CC C C Co om mp pl li ia an nc ce e S St ta at te em me en nt t
Hereby, Nuforce Inc. declares that this device is in
compliance with the limits for a Class B digital device,
pursuant to part 15 of the FCC Rules.
This equipment has been tested and found to comply with the limits for a Class B
digital device, pursuant to part 15 of the FCC Rules. These limits are designed to
provide reasonable protection against harmful interference in a residential
installation. This equipment uses and can radiate radio frequency energy. If not
installed and operated in accordance with the instructions, it may interfere with
radio communications.
There is no guarantee that interference will not occur in a particular installation.
If this equipment does interfere with radio or television reception, the user may
be able to correct the problem by one or more of the following measures:
Reorient or relocate the receiving antenna.
Increase separation between equipment and receiver.
Use equipment on a circuit to which the receiver is not connected.
Consult your dealer or an experienced radio/TV technician for help.
WARNING: Only peripherals complying with the FCC class B limits may be
attached to this equipment.

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Changes or modifications made to this equipment, not expressly approved by us
or parties authorized by us could void the user’s authority to operate the
equipment. This device complies with part 15 of the FCC Rules. Operation is
subject to the following two conditions: (1) This device may not cause harmful
interference, and (2) this device must accept any interference received, including
interference that may cause undesired operation.
Notice for customers: The following information is only applicable to
equipment sold in countries applying EU Directives.
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EU U D De ec cl la ar ra at ti io on n o of f C Co on nf fo or rm mi it ty y
Hereby, Nuforce Inc. declares that this device is in
compliance with the essential requirements and other
relevant provisions of Directive 2004/108/EC.
The manufacturer of this product is NuForce, 382 South Abbott Ave, Milpitas, CA
95035, USA.
The Authorized Representative for EMC and product safety is NuForce, 382
South Abbott Ave, Milpitas, CA 95035, USA.
For any service or guarantee matters please refer to the addresses given in
separate service or guarantee documents.

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For customers in Europe
Disposal of Old Electrical & Electronic Equipment
(Applicable in the European Union and other European
countries with separate collection systems)
This symbol on the product or on its packaging indicates that
this product shall not be treated as household waste. Instead it
shall be handed over to the applicable collection point for the
recycling of electrical and electronic equipment. By ensuring
this product is disposed of correctly, you will help prevent
potential negative consequences for the environment and
human health, which could otherwise be caused by
inappropriate waste handling of this product. The recycling of
materials will help to conserve natural resources. For more
detailed information about recycling of this product, please
contact your local Civic Office, your household waste disposal
service or the shop where you purchased the product.

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SA AF FE ET TY Y I IN NS ST TR RU UC CT TI IO ON NS S
There are two categories of Safety Instructions included in this manual:
Product Warnings, (i.e., what must never be done to assure avoiding those
hazards that could cause bodily injury or property damage); and
User Directions (i.e., what must always be done to assure the safe use of your
device).
The Safety Instructions contained in this manual have been categorized in
accordance with the seriousness of the potential hazards through the use of
Signal Words. Those Signal Words, and their intended meanings, are as follows:
DANGER: Indicates that a failure to observe the Safety Instructions could result
in death or catastrophic bodily injury.
WARNING: Indicates that a failure to observe the Safety Instructions could result
in serious bodily injury.
CAUTION: Indicates that a failure to observe the Safety Instructions could result
in minor bodily injury or property damage.
NOTE: Designates important information that relates to activities and/or
conditions that might result in loss of data and/or damage to your device.

6382 South Abbott Ave, Milpitas, CA 95035, USA • www.nuforce.com • EMAIL: [email protected]
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Sa af fe e U Us se e a an nd d O Op pe er ra at ti io on n o of f Y Yo ou ur r D De ev vi ic ce e
This equipment emits stray RF energy and will interfere with the reception of
signals by airborne electronic navigational devices or medical devices. Do not
operate this equipment near any sensitive medical devices.
WARNING: Never attempt to disassemble, repair or make any modification to
your device. Disassembly, modification or any attempt at repair could cause
bodily injury or property damage, as well as damage to the device itself.
WARNING: Your device is not a toy. Never allow children to play with your
device. Misuse, rough or improper handling of your device by children could
result in serious bodily injury for any of the enumerated safety warnings in this
manual. In addition, always keep all accessories and components out of the
reach of small children as small parts might present a choking hazard. Seek
immediate medical attention if choking occurs or if any small part has been
swallowed.
CAUTION: Never raise the sound volume level too high when using your device
with earphones. An excessive sound volume level could cause damage to your
hearing.

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7
WARNING: To reduce the risk of fire or electric shock, do not expose the unit to
moisture or water.
Read all the instructions before connecting or operating the component.
Keep this manual so you can refer to these safety instructions.
Heed all warnings and safety information in these instructions and on the
product itself. Follow all operating instructions.
Do not use this unit near water.
Keep the component away from radiators, heat registers, stoves, or any other
appliance that produces heat.
Immediately stop using the component and have it inspected and/or serviced by
a qualified service agency if:
Objects have fallen or liquid has been spilled into the unit.
The unit has been exposed to rain.
The unit shows signs of improper operation.
The unit has been dropped or damaged in any way.

8382 South Abbott Ave, Milpitas, CA 95035, USA • www.nuforce.com • EMAIL: [email protected]
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Nu uF Fo or rc ce e u uD DA AC C- -2 2
The NuForce uDAC-2 is a high-performance USB Digital Audio Converter (DAC)
that connects your personal computer's audio with your home stereo, desktop
sound system, or headphones. The quality and versatility of the uDAC's
performance belies its diminutive size. With its extensive power supply, filtering
capabilities and charge-pump circuit as a foundation, the uDAC processes
incoming data via a USB audio receiver. A D/A converter chip then translates the
data to a two-volt analog signal. The NuForce uDAC’s performance equals or
exceeds that of a great many audiophile CD players. The unit’s exemplary
flexibility — analog RCA, digital coaxial, and high-performance headphone
outputs — is bound to satisfy the needs of the most critical music lover.

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Features:
Discrete USB audio receiver and D/A converter
Coaxial S/PDIF output (appears as a separate USB audio device from USB
DAC)
Double jitter-reduction mechanism at data level and at oversampling filter
stage
High voltage 2V analog output
High-quality analog volume control
No capacitors in any of the audio signal paths
Low power consumption; USB self-powered
USB powered, no external power supply required
Specifications:
Input:
USB (USB 1.1, 2.0 compatible)
USB DAC: USB 1.1, 2.0 compatible. USB native bit rate: 32, 44.1, 48, and
96 kHz, 24-bit
Maximum sampling rate: 96kHz
Resolution: 24-bits

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Output:
Analog RCA Output = 2Vrms
Dynamic Range: 90dB
S/N Ratio: 98dB
THD+N 0.05%
Digital Output: coaxial RCA 75-ohm
Headphone output jack, power output: 80mW x 2 @16-Ohm
Power:
USB Bus Powered
Dimensions:
68 x 38x 21mm

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A B Be eg gi in nn ne er r’ ’s s G Gu ui id de e t to o G Go oo od d A Au ud di io o
What qualities distinguish a good audio system?
Let’s start with a misconception. “Wow! I’ll bet that can play loud!” This, or
something like it, is typical of the newcomer’s reaction to an audiophile’s setup,
particularly if the speakers are large.
Why a system’s loudness capability should be the measure of excellence isn’t
difficult to understand. People install often quite costly sound systems in their
cars. Some of the larger specimens seem capable of shaking their host vehicle
apart. The pavement trembles when one passes by. A club’s sound system is in
the same league: ear-splitting, gut-wrenching, floor-buckling output. With the
exception of classical music, which is rarely ever amplified, the same is true for
most live concerts. Domestically, the average boom box can break a lease. TV
ads featuring hard-pumping woofer cones say it all.
On actually sitting down and listening to our hypothetical audiophile’s sound
system, the newcomer will likely say “Wow!” again, followed this time by “It’s so
clear!”
Clarity. The term takes in a host of qualities. As strange as this may seem, one of
clarity’s principal components is silence. A silent audio system — an audio
system that contributes little to no noise of its own — reveals the music all the
more clearly at listening levels from soft to loud.

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Resolution likewise contributes to clarity. Imagine two mounds of sand in bright
sunlight. One mound is mixed with mud. It’s difficult to see its individual grains.
The other mound is free of mud. You have no trouble seeing its tiny, glittering
bits. And so it is with high-quality audio. The music shines through. Nothing
muddies the sonic image. You hear the texture of a singer’s voice almost as if
she’s in the room. Instrumental timbres allow you to distinguish the purposeful
grunge of the rockers’ guitars. Violas differ from violins, likewise oboes from
English horns. A good sound system allows you to make these listening
distinctions.
Soundstage. Another critically important measure of an audio system’s quality
is its ability to project a convincing soundstage. Can you perceive its width and
depth? Is it realistically proportioned? Can you hear the venue as large or small?
Is it clear to you where the musicians perform within the soundstage?
Depending on the style of recording, our audiophile’s sound system provides
the answers. And of course the pleasures.
Speed. An audio system’s superior speed produces crisp, clean attacks: a violin
or trumpet’s edge, a drummer’s rim shot, a marimba’s wooden loveliness –– all
those little delights that mimic live music.
Bass. To return to trembling pavements and hard-pumping woofer cones, the
audiophile’s guest will be pleasantly surprised to discover that a high-quality
sound system’s low end is as tuneful and clean as the rest of the audio spectrum.
Again, no mud. Just lovely, well-defined sounds. A good audio system aims at
naturalness.

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Size. Good audio is not necessarily big audio. If you shop wisely, you need not
spend a fortune to achieve a high level of audio performance. With these
pointers as a guide, the newcomer has a good idea of what to listen for. The least
expensive NuForce components will more than satisfy modest applications. With
our reference-grade components serving as the culmination of all our efforts,
our entire line answers to the same ideal: accurate, vibrant, lifelike sound.

16 382 South Abbott Ave, Milpitas, CA 95035, USA • www.nuforce.com • EMAIL: [email protected]
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DA AC C a an nd d H He ea ad dp ph ho on ne e A Am mp p U Us se er r G Gu ui id de e
Introduction
CD-ripping software is capable of reproducing “bit perfect” digital music data
(16 bit/44.1kHz) from audio CD files stored on the computer’s hard drive. In
addition to CD-quality music, some online sites are now offering 24 bit/96kHz
music files. Thanks to larger and increasingly economical hard-disk capacity,
consumers can store the highest quality music files on their computers. However,
extracting good sound from the computer poses problems.
Poor Sound Quality
As a rule, your computer’s audio doesn’t sound quite right because computer
manufacturers often treat their products’ audio output stage as little more than a
necessary evil. So long as the music signal remains in a digital format, all is well. The
pitfalls appear when the computer converts signals to analog, which is how we
listen to music. Typically, the onboard converter (a.k.a. sound card) is a low-cost
item. Digital circuitry generates noise that often bleeds into the audio stage.
Further, these compromised stages are seldom designed for the low-impedance
power high-quality headphones require. Finally, should you use the computer’s
software to reduce volume, you may actually be listening to eight-bit resolution —
in real-world terms, not at all good.
In sum, these deficits conspire to produce inferior sound. Far better to send the
digital signal to an external digital-to-analog converter (DAC). NuForce Desktop
products employ quality DACs.

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Digital Connections
There are two methods for extracting digital signals from your computer. The
universal serial bus (USB) connection is the de-facto standard for just about all
peripherals: printers, digital cameras, etc. The USB allows the computer to
speedily recognize a connected device. Some computers also incorporate the
Sony/Philips Digital Interconnect Format (S/PDIF), a coaxial connection with
excellent transfer properties.
USB Audio and Performance Optimization
USB specifications define a standard interface: the USB audio-device class, which
allows a software driver to work with the currently available USB sound devices.
Microsoft Windows and Apple Mac provide support for USB audio devices.
NuForce Desktop USB DACs convert USB digital data to the analog signal
headphones and amplifiers require. Equally as important, how the USB DAC
performs affects sound quality.
For more information on this subject, see
http://en.wikipedia.org/wiki/Universal_Serial_Bus.
Some Optimization Tips
To minimize noise and dropouts, connect your audio interface to a port at the
back of your computer. Generally speaking, ports on the computer’s face,
monitor or keyboard don’t perform as well.

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If you use a USB hub, choose one with its own AC power adapter. In areas that
produce high levels of radio or electrical interference, upgrading to a quality USB
cable, i.e., one with extra shielding and a ferrite bead (the cylindrical collar on
one end of the cable) to help eliminate noise. Once you’re properly connected,
your computer’s operating system should automatically detect your NuForce
product. From that moment on, all you need to do is enjoy the music.
Windows PC Driver Optimization
ASIO4ALL is a hardware-independent, low-latency ASIO driver for WDM audio
devices that employs WDM Kernel-Streaming and other sophisticated methods.
What You Should NOT Do
Do not tamper with or replace your existing sound-card drivers.
Do not install any kernel-mode components that might affect your system’s
stability.
Do not “over-clock” or operate your audio hardware in ways that have the
potential to do harm. This will void your warranty. (In certain cases, your
hardware’s manufacturer states that the use of ASIO4ALL will void your warranty.)
No software-driver optimization is required for the Apple Mac OS.
S/PDIF Connection
The Icon HDP permits an S/PDIF connection from your computer, if that’s your
preference. For best results, use a high-quality S/PDIF cable. Once the
connection is made, select S/PDIF in your System Preferences Audio Device
settings.

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Analog Connections
You need only connect headphones to your NuForce device’s headphone jack
and adjust for volume with the unit’s volume control. If connecting to an
external amplifier or stereo receiver, you will require a quality stereo
interconnect with a standard male RCA connector for plugging into the NuForce
device and an appropriate connector at the other end (usually, an RCA).
Note on Headphone Use
Headphones present a challenge to amplifier designers. There are two basic
types: the over-ear (OE) in general use in the recording industry and the smaller
in-ear (IE), a.k.a. ear-bud, commonly used with portable devices such as MP3
players. Given the range of available OE and IE headphones, in attempting to
deal with all of them, your computer’s headphone output is optimized for none.
Your NuForce Icon product will make a world of difference.
The reason is simple enough. Various OE and IE phones cover an expanse of
electrical impedances from 16 to 600 Ohms and differ in other significant ways.
Sensitivity is a term that expresses how loud the headphones will play at a given
amount of electrical power, e.g., x number of decibels per milliwatt (0.001 watt)
of power, expressed as xxxdB/mW.
Typically, OE types exhibit sensitivities of about 100dB/mW, whereas IE devices
can be 10dB higher or more, e.g., 110dB/mW. Assuming a 10dB difference, the
lower sensitivity OE headphones require ten times more power to achieve the
same volume as the IE type. If you’re using OE headphones, you’ll appreciate the
NuForce Icon Series’ power capability. Your headphones will sound clearer and
more natural. If you use IE headphones, owing to their higher sensitivity, you

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may notice a small amount of background noise. Conversely, you will hear weak
signals more readily than would be the case with lower-sensitivity OE types.
We are not discussing a product defect. Electrical noise arises from many factors,
one of which is the amount of amplification the Icon product provides.
Irrespective of type or design, electrical circuits introduce noise. If the device
amplifies the signal, the noise coming into it will likewise be amplified. Further,
the amount the device itself creates will also be greater. These are facts of
electrical life that good design can mitigate. In the case of IE headphones, noise
can be minimized or all but eliminated by reducing the amplifier’s gain. But to
do that, the advantage the amp offers to OE headphone users would be
sacrificed. Performance benefits for one type of product diminishes those of the
other. As always, effective engineering requires compromise. In this regard, the
NuForce Icon Series of products offer good, real-world solutions. Noise will be
low in some cases, and in others, quite imperceptible. Most importantly, OE
headphone users will benefit from the power they require.
For further reading:
http://www.nuforce.com/hp/support/icon-hdp-noisefloor.php.