NuForce Technical FAQ

General Issues:

Q:  What speaker impedance is recommended to match best with the Icon-2 or Icon Amp?

A:  We recommended using only 8-ohm or higher speakers, except in the case of our S-X loudspeaker.  The S-X has a special circuit and driver arrangement specifically designed to match the Icon-2/Icon Amp.  Although there may be the occasional exception, conventional 4-ohm speakers can often cause pre-mature activation of the protection circuit within the Icon, even at low volume.  You see, a 4-ohm speaker requires twice the current compared to an 8-ohm speaker, and the advertised impedance of most all speakers is only a "nominal" rating.  That often means their impedance can be lower at some frequencies.  Therefore, a 4-ohm rated speaker's impedance may go as low as 3 or even 2-ohms.  If so, that would engage the Icon product's protection circuit well before a reasonable volume could be achieved, so that's why we can't generally recommend them.  There may be exceptions to this though, so you would need to check the impedance graph of the speaker in question (assuming one is available)in order to be sure.

 

Q:  Does the Icon's volume control also adjust the level of the music signal coming from the RCA jacks at the rear of the unit?

A:  Yes.

 

Q:  What is the best volume setting to use on my computer's media player software?

A:  Generally speaking, the setting should be set to full volume – 0dBFS (Full Scale).  This setting will provide the greatest dynamic range possible from the digital audio data that comprises the recording.  Nevertheless, if you experience a channel imbalance when listening to headphones, you may wish to deviate slightly from this recommendation.  See questions & answers below.

 

Q:  My headphones have a relatively high sensitivity rating, such that I only need to turn the Icon product's volume up to around 9 or 10 o'clock.  At that setting there seems to be a slight channel imbalance where one side plays louder than the other.  The effect goes away when I turn the volume up higher, but then the volume is too loud.  Is there something wrong with my unit?

A:  No.  This is a common occurrence in moderately priced consumer audio products.  The effect is due to the limitations in manufacturing tolerances of the volume control.  In order to improve the accuracy of low-level volume settings, manufacturers of high cost audiophile products often resort to "stepped attenuators," where discrete resistor networks are selected for every volume setting.  The volume selection is then made by a rotary-switch volume control, which simply provides multiple position settings for the selection of the appropriate resistor network.  Unfortunately, such extremes of engineering cannot be employed in the price range of our NuForce Desktop products.  For further information, please see the web page at the following link:
http://www.nuforce.com/hp/support/analog-volume-graph.php

 

Q:  Is there an easy solution to the above channel imbalance problem?

A:  Yes, in fact there are two and both involve adjusting your software media player settings (iTunes, Microsoft Media Player, Foobar, J River Media, etc.).  The easiest is to simply turn the software's volume control down o where you have to compensate by increasing the volume control setting of the Icon product.  Critics of this solution though often claim that doing so comes at the sacrifice of loosing low-level detail and resolution.  While technically this is true, one must consider the actual net audible loss involved.  The fact is, a decrease of -6dB of the software volume setting only suffers a loss of a single LSB (Least Significant Bit), and in most cases a reduction of –6dB would be more than sufficient to correct for any channel imbalance.  The audible effect of "dropping" the LSB is almost imperceptible to even a trained listener, and only occurs when the recording actually uses the full dynamic range available.  With a 16-bit recording of exceptional quality, the effect *may* be barely detectable.  Conversely, when playing back a 24-bit high quality recording, any such effect would almost never be noticed even under the best circumstances when using the very best headphones.

The second solution depends on the abilities of your media player software.  If it has a L/R Balance adjustment, simply move the control in the direction of the weaker channel.  The same loss of resolution issue as above still applies, but only to the channel that the control is being moved away from, and usually to an even lesser degree.

 

Q:  My Icon produces sound from the headphone jack, but I do not get any signal to the input of my external amplifier.  Is it defective?

A:  Make sure that you have removed the headphones or any headphone adapter from the Icon’s  headphone jack.  Line-level RCA outputs are disabled when any type of plug is inserted into the Icon’s  headphone jack.  We provide this feature so that you won’t have to turn off your external amplifier every time you want to listen to headphones only.

 

Q:  Is it possible to connect my iPod or iPhone to the uDAC-2, Icon-2, Icon HDP, etc., such that the digital music signal is externally converted back to analog by the DAC stage of the Icon?  I am hoping that this is possible because it should improve the sound quality.

A:  No, unfortunately this is not possible.  The iPod is a relatively simple device that is referred to in computer terminology as a "client" device, and the Icon products mentioned are client devices as well.  In that, they are both relatively simple products that can only communicate under the control of a computer.  For communication, the iPod must be connected to a type of "intelligent" device that functions on some basic level similar to that of a computer, which we then refer to as a "host" device.  The host must request that digital data be sent to it from the iPod, as otherwise it will not do so on its own.  Therefore, in order to accomplish the external Digital to Analog conversion as suggested, the iPod must be connected to an external DAC-based device that has the required intelligence in the form of a simple processor and Operating System.  In order t fulfill this need, NuForce now offers the new Icon iDo, which can be seen at the following web page:
http://www.nuforce.com/hp/products/ido/index.php

 

Q:  When I plug the NuForce Icon USB DAC-based device into my computer, for some reason the computer does not recognize the unit and I get no sound.  Is there anything I can do?

A:  While all NuForce Icon USB DAC-based products are designed to be plug-&-play compatible, for reasons beyond this FAQ’s scope, the  process occasionally fails.  The problem is usually easy to fix. Simply go into your Control Panel/Sound Device (Windows) or System Preference (Apple Mac) settings and adjust them manually.  Please refer to the information located at the NuForce web page located at the link immediately below.  While Windows XP or other operating systems may look a bit different from what you see on the page, the concepts remain pretty much the same. You will likely be able to make the correct changes based on the information you will find there.  http://www.nuforce.com/hp/support/usb-audio-setup.php

 

Q:  When I connect the NuForce Icon to my computer I get an error message stating that "the necessary driver is not found."  Do you supply a driver with your products, and if so, how can I get one?

A:  All NuForce products designed to avoid the need for any type of additional driver installation.  Our products operate using the industry standard ASIO4ALL USB audio driver supplied with virtually all modern operating systems (including Windows, Mac & Linux).  If you are getting this error message, it is likely that the driver has somehow been deleted, possibly during the installation of some other audio software.  In any case, you can find and download the latest version of this driver at the following link:http://www.asio4all.com/

 

Q:  I have an Apple Mac computer and for some reason I get clicks, pops and intermittent audio from my NuForce product.  Is the device defective or is there something I can do to fix this problem?

A:  There are several potential problems that can produce this effect. Often the difficulty simply consists of a background application or service that interrupts or interferes with the digital audio stream. If you have any other devices connected on the USB bus, or are using a web browser, or have the USB DAC near another device that is producing digital noise, these can certainly contribute to the unit's less than optimum operation.

Often, plugging all the devices connected to the computer system to the same AC multi-outlet power strip can resolve this issue. Stray electrical fields, DC offsets, and ground loops are capable of interfering with the USB DAC's proper operation.

If you happen to be running multiple applications on the computer, try reducing the playback bit-rate to 16 bit 44.1kHz for standard CD audio resolution. This helps to reduce the load on the computer's CPU, since the system is not required to upsample audio streams on the fly.

The more you are able to lower the demands on your system's CPU, the better the result. If you have an audio playback application like Foobar, you can try adjusting the playback buffer length to alleviate this problem.

Finally, rebooting the system from time to time may be all that is required. Many individuals leave their computers on for days at a time without rebooting, which can cause the system's RAM to become fragmented and inefficient. Rebooting the computer clears the RAM and may very well relieve the situation.

 

Q:  I can hear hissing sounds coming out of my Icon product.  Is it defective?

A:  Generally speaking, this is not a problem related to the product.  Some people with sensitive hearing and/or a noisy computer will end up hearing some low-level noise.  In some cases, this could be an issue with the quality of the USB signal coming from your computer. Below are the results of an experiment we conducted to test the uDAC-2 combined with a Mac Power Book vs. the uDAC-2 and a ThinkPad PC.

Highest Noise:  Connected uDAC-2 to ThinkPad (X200), ran Foobar2K and paused the music.  Could hear noise at around 12 o'clock volume setting.
Moderate Noise:  Connected uDAC-2 to ThinkPad without running Foobar2K.  Could hear noise at maximum or after 3 o'clock volume setting.
Less Noise:  Connected uDAC-2 to Mac and ran iTunes, then paused the music.  Could only hear slight noise at maximum volume setting.
Least Noise:  Connected uDAC-2 to Mac then switched Sound Device settings to Internal speaker and muted the volume.  Could hardly hear any noise at maximum volume setting.

 

Q:  The NuForce Icon I have is being connected to another amplifier.  Since each product has its own volume control, what is the best setting for each?

A:  Generally speaking, the best method is to follow the "lowest noise rule," which states that the lowest noise and distortion willresult from applying the most audio signal gain (amplification) at the earliest stage in the system.  The idea is that, as the signal passes through following stages, it picks up noise and distortion along the way.  If  the bulk of the gain is applied near the end of the system,you will also be amplifying any noise en route that was added to the signal.  If  possible, it is best to avoid amplifying any noise.

In practice, this concept is not always easy to implement to an optimal level.  Ideally, there should be some way of monitoring the signal so that one uses as much gain as possible (before the onset of distortion) at the very first stage in the system.  Without test equipment to perform this monitoring function, the alternative is to employ listening tests as outlined below.

To begin, such a test involves turning up both the Icon and amplifier's volume controls to about 12 o'clock.  Then turn the Icon's volume control up while simultaneously turning down the amplifier's volume control in order to maintain a constant average volume from the speakers. You should repeat this process while listening for a change in timbre, wherein the music’s higher tones start sounding excessively bright or even a bit irritating.  That is the sound of distortion and therefore the limit to which you can turn up the Icon's volume.  Once that level is reached, you would then turn the Icon's volume control down to where the sound regains its smoother nature.  From that point forward you should adjust the speaker volume up or down to taste via the amplifier’s volume control, leaving the Icon's volume control at the same setting all of the time.

A simpler and faster alternative is to turn the Icon product's volume control to about 2 o'clock and adjust the speaker volume to taste using the amplifier's volume control from that point forward.  In most cases, the Icon’s 2 o'clock setting is quite close to optimal.

 

uDAC-2/uDAC-2 HP

Q:  How many inputs does the uDAC-2 have and what kind of signal will it accept?

A:  It has only one USB input and must be connected to a computer that sends a digital audio signal.

 

Q:  There appears to be a coaxial jack at the rear of the uDAC-2.  Is that an input or output and what is its intended use?

A:  That connector is a digital S/PDIF output.  When connected to an external DAC the uDAC-2 functions as a convenient USB-to-coaxial converter.  In such applications, one would expect that the external DAC in question is a larger and (hopefully) higherperformance device than that of the uDAC-2.  When this connection is used, the signal remains in a digital form and therefore essentially bypasses the uDAC2’s built-in DAC.  The digital signal is still presented to the uDAC-2's internal DAC section and, for whatever reason, can be used simultaneously, e.g., in a recording studio where the engineer would like to monitor the music signal via headphones before it is input to a digital mixer.

 

Q:  Why does the unit seem to get hot to the touch at times? Is there any way to prevent this?

A:  In most cases the problem arises when  the 5-volt DC power supplied by the computer’s USB port/buss is not up to providingthe uDAC-2 with sufficient power.  This is a fairly common occurrence. Many computers limit the amount of current made available to their USB ports for use in powering external devices.

The current draw of the uDAC-2 is such that the voltage delivered by the computer's 5-volt supply will drop slightly below 5 volts. The uDAC-2’s voltage regulator circuit tries to compensate for the lack of voltage, which accounts for the excess heat.

One of the best ways to avoid this problem is to use an inexpensive powered USB hub between the computer and the uDAC-2. Instead of the computer, the powered USB hub will provide the needed power to the uDAC-2 at a more robust level.  In addition to the elimination of the excess heat, as a secondary benefit, the sound quality may improve.

 

Icon-2

Q:  How many and/or what kind of inputs does the Icon-2 provide?

A:  It provides (1) digital USB input and (2) analog inputs (1-RCA & 1-3.5mm).

 

Q:  I want to connect a sub-woofer to my system.  What is the easiest way to do that?

A:  The Icon-2 provides a line-level output signal via a 3.5mm stereo "mini" jack at the rear.  Assuming your sub-woofer requires a standard stereo RCA input connection, you will need a splitter-type cable.  This cable will have a stereo 3.5mm "mini" plug at one end for connecting to the line-out of the Icon-2, and a pair of L&R RCA plugs at the other end for connecting to your sub-woofer’s inputs.

 

Q:  The Icon-2’s speaker outputs seem different from those I’ve seen on other amplifiers.  How do I connect speaker cables to these?

A:  NuForce provides 1-meter cables that have the correct connector at one end and standard
banana plugs at the other end for connecting to your speakers.

 

Q:  My speakers don't accept banana plugs.  Now what do I do?

A:  Some have suggested cutting off the banana plug, stripping the insulation off of each individual wire and twisting them together. While that is possible, it tends to be wasteful, especially if you were to acquire speakers that accept banana plugs, or even if you decide to sell your Icon-2 at some later date.

The best thing to do is purchase a pair of inexpensive, ready-made CAT-5 network cables. The connector type used in the Icon-2 is a standard RJ45, commonly used for network cables.  Simply cut off one end of each cable and strip/twist the wires as suggested above.  The wire color code for this procedure is located on the bottom right side of the Icon-2 web page:http://www.nuforce.com/hp/products/icon2/index.php

 

Q:  I want to put my speakers on the other side of the room. How can I extend the provided cables?

A:  Purchase a pair of inexpensive network cable couplers along with an additional pair of sufficiently long network cables.  Plug the long cable into the Icon-2, with the coupler attached on the other end.  Then plug the 1-meter cable provided with the Icon-2 into the coupler and the other end into your speakers.

 

Icon HD/HDP

Q:  What is the difference between the Icon HD and the Icon HDP?

A:  The ONLY difference is the number and type of inputs.  Their circuitry and overall performance are identical.  The Icon HD has only one input – a USB-type for connecting to a computer.

Along with the USB input mentioned above, the Icon HDP also has a stereo pair of RCA analog inputs OR a stereo 3.5mm analog input (when inserted).  In addition, the Icon HDP has a digital coaxial-S/PDIF input OR an optical-Toslink (when inserted.).

 

Q:  Considering that the Icon HD is similar to the uDAC-2 in function and features, why is it over twice the price of the uDAC-2?

A:  While their basic features and functions may be similar, the performance of the Icon HD (and Icon HDP) is a definite stepabove.  Independent measurements have compared Icon HDP to 25 similar products.  For more information regarding these comparisons, refer to this Adobe Acrobat file: http://www.nuforce.com/hp/docs/review/DAC-Headphone-Amp-Tests-PlotOnly.pdf

The Icon HDP ranked among the top three products with regard to measured performance. One of the competing products is priced at over $10,000.00!  We feel, and most would agree, that the Icon HD/HDP represent exceptional value that more than compensates for their relatively higher price.

 

Icon iDo

Q:  What is iDo?

A:  The NuForce Icon iDo is a complete Digital-to-Analog docking interface and headphone amplifier for the Apple iPod, iPhone or iPad.
iDo dramatically improves the sound quality, providing a greatly enhanced listening experience.  iDo gives you the ability to listen through a wide variety of output devices such as a home stereo system.

 

Q:  How does iDo improve the audio quality?

A:  Instead of receiving the audio signal from the headphone jack, iDo extracts the USB audio signal digitally and converts it via high-end D-to-A (digital-to-analog) converters.  This provides a cleaner, clearer sound to the listener, minimizing distortion and providing greater clarity.  It is able to extract the audio data in its original digital form utilizing Apple Lossless Encoding, perserving the recording's most minute details and allowing the listener to experience the music's full potential.  iDo features audiophile-grade 24-bit D/A converters, a built-in headphone amplifier, digitally controlled analog volume control, as well as RCA and S/PDIF connectors.
iDo offers bit-perfect, low jitter USB host mode operation with no sample rate conversion.

 

Q:  What Apple devices are compatible with iDo?

A:  The Apple iPod touch (3rd and 4th generation), iPod classic, iPod nano (6th generation), iPhone4, iPhone 3GS, iPhone 3G, iPad 2, the original iPad, and Apple remote control are compatible with iDo.

 

Q:  Does iDo work with other USB devices?

A:  No, only the supported iPod devices listed above are compatible with iDo.

 

Q:  What audio output devices can I connect to iDo?

A:  iDo features a 3.5mm headphone jack, RCA connectors, and a S/PDIF connection.  An adapter (not included) is required to connect 6.3mm headphones.
Devices such as stereo receivers can be connected via RCA or S/PDIF.

 

Q:  How do I power on iDo?

A:  The power button is located on the far right of the back of the iDo device, and is used to power on iDo.

 

Q:  How do I adjust the volume on iDo?

A:  The volume knob is located on the far left of the front of the iDo device, and can be used to adjust the volume level.

 

Q:  What does the green light mean?

A:  The green light indicates that an iPod USB device is connected to the iDo device.

 

Q:  What do the blue lights mean?

A:  The blue light indicates the volume level of iDo.

 

Q:  The iPod device is connected to the iDo, but the green light is not on.  What's wrong?

A:  Try disconnecting your iPod device.  On to the iDo, cycle power off and then back and reconnect your iPod device.  If that doesn't work, check the iDo compatibility list to make sure your device is compatible with iDo.  In addition, at some point it may become necessary to update your iDo operating system as newer versions become available.

 

Q:  The iDo green light is on, but there is no sound.

A:  Please check the following:
(a) Check the iDo’s volume setting.
(b) Check the iPod volume by using the remote. Remember that the remote has to be pointed at the iDo.
(c) Check headphones for proper connectivity. If they are plugged in, the RCA output will be switched off automatically.

 

Q: Can I use an alternate power supply with iDo?

A:  No, do not use any non-factory power supply with iDo as it can damage the iDo as well as any connected iPod device!!

 

Q:  Can I use the Apple Remote Control with iDo?

A:  Yes, the Apple Remote Control is compatible with iDo, but is not required to operate it.  iDo supports Play, Pause, Volume Up, Volume Down,
Previous Track, and Next Track functions from the Apple Remote Control.

 

Q:  There is no remote control included with my iDo, so do I have to purchase that separately or is it missing from the package?

A:  The NuForce Icon iDo supports the standard Apple Remote Control for use with iPod devices.  Therefore, NuForce does not provide a remote control.  Rather, an Apple Remote Control is available from your authorized Apple retailer, or it may be provided free with certain Apple products.  The Apple Remote is not required to operate iDo, and is only a convenience feature.

 

Q:  What features are controlled on the iDo by the Apple Remote Control?

A:  The remote functions supported are: Play, Pause, Volume Up, Volume Down, Previous Track, Next Track.

 

Q: What happens to the iDo when a phone call comes in (to iPhone)?

A: When the iPhone is connected to iDo and you receive a call, the volume will automatically fade out, allowing you to answer your call.
There is no need to disconnect the iPhone from iDo before answering the phone.

 

Q: How do I charge my iPod device with iDo?

A: iPod devices automatically charge via the USB connection when connected to iDo.  Please make sure the iDo is powered on before connecting an iPod device.

 

Q: Can I connect or disconnect an audio device without powering down?

A: Yes, but you might want to adjust the volume level down before doing so.

 

S-X Loudspeaker

Q:  How can I mount my S-X speakers to the wall?

A:  There are two hidden screw holes at the rear of the enclosure.  They are located behind the layer of soft padding above the Ethernet cable plug.  Simply detach the soft layering and use these holes to mount the S-X in whatever location you prefer.

 

Headphones/Earphones

Q:  My NE-700Ms have had to be replaced a second time.  It seems that one side or the other keeps failing.  Is this poor qualitycontrol on NuForce's part or am I doing something wrong?

A:  Although our earphones look similar in many ways to other, less expensive types, they are a true high-performance product. High-performance products of any type tend to require special handling, as would, for example, a precision race-car or delicate timepiece.  The technology that makes possible their extreme level of performance and comfortable, lightweight construction, also makes them vulnerable to mishandling.

Specifically, the very small diaphragm that creates the sound must be able to move freely in order to produce deep bass tones.  That flexibility also subjects them to extremes in air pressure that frequently develops when inserting or removing them from your ear canal. The near-vacuum seal’s positive or negative pressures can make the diaphragm travel beyond its limits.  If this happens, their close-to microscopic wires can be stretched to the breaking point.  Should they break, the earphone cannot be repaired.

In order to avoid this kind of failure, insert or remove the earphones slowly, thus allowing the pressures to develop gradually and equalize with the outside air pressure. This precaution should prevent any such failure.