For a complete history and explanation of USB standard (1.0, 2.0, 3.0, 3.1) and port types (A, B, C, micro, etc), refer to Wikipedia USB article.

NuPrime communicates and decode digital music from the computer through USB Audio (this is a software standard, not physical USB standard). USB Audio is a software standard that defines how audio devices can communicate with the computer to play music. The USB standard and port type set the physical properties of how devices are to be connected to the computer and the speed limit.

The USB communication is always between a host and a client devices. Some devices such as smartphone or tablet can act as USB host or client device. When a smartphone is connected to the computer, it functions as a client device to the computer. Printer and USB hard drive are USB client devices. Client devices can not work with each other, unless one of the device has the capability to become a host. NuPrime’s DACs (including Digital Integrated Amp) are all USB client devices and they are designed to play music from computer, smartphone or tablet.

Some of the NuPrime models come with two Type-A ports. One of the ports is a standard USB 2.0 port (for audio, USB 2.0 is the standard and USB 3.0 is backward compatible with USB 2.0) for USB audio use. The other port is a proprietary NuPrime digital port that uses the same USB Type-A connector. It is not a USB standard! NuPrime wireless devices (Bluetooth dongle, WiFi audio receiver) use this custom digital port for 5V power as well as digital music signals (in S/PDIF format). For example, if NuPrime WR-100 is to be connected with a non NuPrime DAC, it would have to be powered by a 5V power adapter and connect its optical S/PDIF output to the DAC. But if WR-100 is connected to NuPrime IDA-8 or DAC-9, a single cable is all that is needed.

USB 3.0/3.1 is also compatible with USB Type-C, the latest plug design that’s just starting to gain adoption. This reversible plug is distinct from USB 3.1, though manufacturers may choose to support both at once. For example, the 2015 MacBook and the second-gen Chromebook support the USB 3.1 standard on their Type-C ports, while the OnePlus 2 uses the USB 2.0 standard despite a Type-C port. Don’t confuse the USB standard with the port type.

USB Host & USB Client

USB Audio is a standard for digital audio used in PCs, smart phones and tablets to interface with audio peripherals. The source device that produces the data is called the USB Host and the receiving end is the USB Client. So, if a smartphone is connected to a computer, the computer is the host and the phone is a client. But if a DAC is connected to the smartphone, then the phone is now the host and the DAC is the client.

Audio only needs USB 2.0

Most USB audio interfaces are USB 1.0 and USB 2.0 compatible, so you should have no problem getting a device to work with any computer manufactured in the last 5 years. A USB audio interface attaches to the computer with a standard USB connector and to the device itself with any number of other connectors, ranging from proprietary connections to standardized connections. USB Audio devices do not need the bandwidth of USB3.0 and USB3.0 is backward compatible with USB2.0. USB 2.0 can handle bandwidth of 480 MB/second. To put this into perspective, 24 bit/192 khz audio–the highest bandwidth in commercial use–uses approximately 10 MB/second per track of audio. So, a stereo recording would take approximately 20 MB/second or 5 percent of the possible USB 2.0 bandwidth. This large amount of bandwidth available allows for USB audio interfaces to accommodate just about any recording or playback scenario imaginable.

Setup

Steps to setup your computer to use external USB Audio device such as a DAC (Digital to Analog Converter):

• Connect the USB Audio device to the computer (before installing any device driver).
• Install the Windows device driver if it is required (Mac computer does not need to install USB Audio device driver)
• Go to the System Preference/Setup and look for Sound device setup. Choose the desire USB Audio device (e.g. NuPrime uDSD, Encore mDSD, …)
• For further information about how to configure the music player software for high resolution music playback, download this user guide: https://nuprimeaudio.com//images/productpage/NuPrime-USB-Playback-Guide.pdf
• Occasionally Windows users might encounter driver error or not able to install certain device driver files. This is usually due to conflict with previously installed driver. Unfortunately there is no simple solution to this problem. Try the following steps:
  • Uninstall NuPrime USB audio device driver.
  • Go to Device Manager and look for any USB audio device driver (or any device driver) that has an error mark next to it.
  • Delete the driver.
  • Install NuPrime USB audio device driver again.

DAC’s Volume Control Basic

A DAC typically has a mix of analog and digital inputs. Some DACs convert the analog input into digital to utilize the DAC’s internal digital volume control and inputs selection, avoiding expensive analog preamp and volume control as described above. The performance degradation of the analog input that has to go through A2D, volume adjustment, and then D2A depends on the implementation, which is beyond the scope of this discussion. Digital inputs, on the other hand, should go through the high-end DAC’s internal volume control for best performance. Therefore it makes sense to best adjust the volume in the digital domain for digital signals and use an analog preamp and volume control for analog inputs.

High End Analog Volume Control Basic

In traditional pure-analog designs, a switch-resistor network for volume control works best but is very expensive due to many high precision discrete resistors. Next is a high-quality volume pot. You rotate the Pot to change resistance, which in turn attenuates volume. A volume pot is non-linear and has balance issues at low volume.

All the NuPrime high-end DACs and Integrated Amps use a mixed analog and digital volume-control design. The digital volume control’s 0.5db steps are sent to the DAC for the best possible result.

The DAC’s analog output and analog inputs from other sources then go through a low noise and low distortion resistance ladder circuit design (implemented as an IC) similar to switch-resistor network.

In conclusion, we feel we’ve developed the best type of mixed digital and analog volume control and preamp for a modern DAC.

It depends on how good the volume control on your preamp or integrated amp is. Basically you want to set the volume of the less accurate preamp as high as possible (90% of maximum for example) and use the better preamp to make the fine adjustment. If both are equally good, set both to around 0db (mid-point). It is easier to test your preamp at low volume. Set DAC-9 to near maximum volume and try it out with your integrated amp. Does the music sound well detailed at very low volume? Do the opposite and compare again.

Using Bluetooth and WiFi Audio Receivers and Dongles

Our DACs follow the standard XLR pinout.

Pin 1 = Ground; Pin 2 = HOT (+); Pin 3 = COLD (-)

We recommend JRiver Media Center for its ease of use and setup. Please refer to this setup guide: https://nuprimeaudio.com//wp-content/uploads/JRiver-Configuration-for-DSD-Playback.pdf

For Foobar please refer to this general purpose USB audio playback guide: foobar2000_dsd

Use the settings of MQA Core Decoder option in Roon. The options that work are: “decode and render” and “decode only”. Decode and render option should provide a better sound.

DAC-10 / 10H line out can be turned off by holding the Mute button for 3 seconds. The line out will not automatically turn off when the headphone is inserted because there are multiple headphone outputs.

To enable the line out again, press and hold the Mute button for 3 seconds.

If you are not familiar with USB audio device, please read the FAQ topics on “What is USB Audio and how do I configure Windows or Mac computer for USB audio and the DAC ?” and “USB Standard and Ports”

The standard USB audio cable that comes with your iOS or Android device can not be used to connect the DAC. You will need a different cable that treat the iOS or Android device as the host, and the DAC as the client.

• iOS device – use a genuine or Apple MFI approved USB Camera Adapter cable
• Android device – use a quality USB OTG cable

iOS Device

USB Audio has always been supported by iOS. You can use Apple USB Camera Adapters to import photos from your digital camera. You can also use Apple USB Camera Adapters to connect other USB devices to your iPhone, iPad, or iPod touch. If you’re using an Apple USB 3 Camera Adapter, you need an iPad with iOS 9.3.

Some USB devices need more power than your iPhone, iPad, or iPod touch can provide. If you connect one of these types of USB devices, you might see an alert that says “attached accessory uses too much power.” Try one of these steps:

• Connect the USB devices to a powered USB hub or secondary power source.
• Use a Lightning to USB 3 Camera Adapter. The Lightning to USB 3 Camera Adapter has a built-in lightning port, which you can connect to a USB power adapter. This provides power to your iOS device and connected USB device.

Android Device

Prior to version 5.0, the support for USB audio is spotty. Some device manufacturers do a better job than others. In general, Android OS 4.1 and above provide support for USB audio device. If you have doubt, check with your device manufacturer or search for help online. Please do not ask our support staff. In general, similar to iOS device, if the DAC is connected and functioning properly, the Android OS will send the audio to the USB port. There is no need for any system configuration.

We strongly recommend USB Audio Player PRO for high resolution music playback.

Similar to iOS device, if your USB device consumes more power than allowed by Android device, you will need to power the USB device. If you are technically inclined, here’s a useful article: http://source.android.com/devices/audio/usb.html

Powered USB DAC

NuPrime DAC-10/10H, DAC-9, IDA-16, IDA-8

Externally Powered USB DAC

• NuPrime uDSD – should always be connected to computer or a powered USB hub
• Encore mDSD – can be connected to mobile iOS or Android devices directly, provided that the headphones used do not draw too much power. mDSD should be connected to headphone before connecting to the mobile device. If you don’t hear any sound from iPhone or iPad, try to lower your iDevice system volume, then pressing the mDSD volume up first, then increase the system volume.

How to connect to a powered USB hub – you will need a USB Type A to Type A cable for connecting the Android USB OTG Cable or Apple Camera Adapter Cable to the USB hub.

There are two ways to determine the sampling rate:

1. Use meta data from the source music. If the meta data is wrong or the source does not contain any sampling rate data, then NuPrime device will not display the correct sampling rate.  Even if the display does not show the correct sampling rate, the decoding will not be affected. The actual sampling rate is detected during the decoding process. Products using this method are: IDA-16, DAC-10 and uDSD
2. Use SRC (sampling rate converter implemented in FPGA) to detect the clock of the source music to determine sampling rate. Products using this method are: IDA-8, IDA-6 and DAC-9.

The sampling rate is displayed during the following conditions:

1. When an input is first selected, the Input Number and Sample Rate are displayed. Unless there is a change in input or sampling rate, the initial sampling rate will not be displayed again.
2. The sampling rate is displayed whenever there is a change in Input Source or music sampling rate.

Then follow this application note:  https://www.synology.com/en-global/knowledgebase/DSM/help/AudioStation/playmusic

“Enable high quality output for USB speakers” should be selected in the Audio Station’s Advanced Setting.

All the Line Outs or Subwoofer Outputs from all the DACs and Integrated Amps are full range.nnThe subwoofer outputs from home theater products are filtered according to the device setting.

1. Check the Sound setting in the Control Panel. Verify that the NuPrime DAC is selected. If it is not showing, the device driver was not installed correctly.

2. Go to Device Manager to check the USB audio device driver is installed and without any conflict. Remove conflicting USB audio devices. There are several places to check:

a) The NuPrime USB audio device listed under Device Manager.

b) In Device Manger, in “Sound, video and game controllers”, there should be a NuPrime USB audio device. Check that there is no “error status”. Right click to “Update Driver Software” if the status is “error”.

3. Reboot computer.

4. Check that your USB cable is not defective.

WASAPI – Applications communicate with the audio driver through Sessions, and these Sessions are programmed through the Windows Audio Session API (WASAPI). In general, WASAPI operates in two modes. In exclusive mode (also called DMA mode), unmixed audio streams are rendered directly to the audio adapter and no other application’s audio will play and signal processing has no effect. Exclusive mode is useful for applications that demand the least amount of intermediate processing of the audio data or those that want to output compressed audio data such as Dolby Digital, DTS or WMA Pro over S/PDIF. WASAPI exclusive mode is similar to kernel streaming in function, but no kernel mode programming is required. In shared mode, audio streams are rendered by the application and optionally applied per-stream audio effects known as Local Effects (LFX) (such as per-session volume control). Then the streams are mixed by the global audio engine, where a set of global audio effects (GFX) may be applied. Finally, they’re rendered on the audio device.

Audio Stream Input/Output (ASIO) is a computer sound card driver protocol for digital audio specified by Steinberg, providing a low-latency and high fidelity interface between a software application and a computer’s sound card. Whereas Microsoft’s DirectSound is commonly used as an intermediary signal path for non-professional users, ASIO allows musicians and sound engineers to access external hardware directly.

Some entry level consumer devices have optical outputs with high jitter and that can affect the locking of optical signal with some model of NuPrime DAC. If this is determined to be the problem, you can use an optical to analog converter such as “Musou Digital Optical Coax to Analog RCA Audio Converter Adapter” (available from Amazon.com) to convert the noisy optical signal to the DAC’s analog RCA inputs.

If your Windows USB audio is not working, go through the following diagnostic:

1. Download and run Windows USB Troubleshooter
2. Following these manual troubleshooting steps.

To rule out any hardware failure, you should also verify that the NuPrime product is working with another computer.

Mac OSX does not support native DSD. It only supports DoP (DSD over PCM).  Since encoding DSD into DoP requires twice the bandwidth, when using NuPrime’s DAC with Mac OSX, the support of DSD is limited to half of the maximum decoding capability of the DAC.

From Audirvana:

“To listen to DSD files from a DAC, Audirvana Plus transmits the DSD files to the DAC using the “DSD over PCM” protocol that requires markers, and using this protocol requires twice the bandwidth over the native DSD signal only. In order to get the best possible result, you need to use Audirvana Plus with a Native DSD DAC. However, if your DAC is not DSD compatible, Audirvana Plus will perform downsampling to PCM using a very high quality 64 bit algorithm.

Please note : The “DSD over PCM” protocol requires markers to identify the signal as DSD, so using this protocol requires double the bandwidth compared to the native DSD signal alone. This can reduce the maximum DSD frequency that can be used with DAC by half compared to the frequency that can be reached under Windows. This may explain why a DSD 512 DAC can stop at DSD 256, and DSD256 DAC can stop at DSD128.”

“DoP is a method to encapsulate DSD native signal in PCM stream. There is no conversion to PCM. It is true DSD signal, just that OSX thinks it is PCM. The DAC recognises it correctly and decodes the DSD signal. So DSD over PCM 1.0 is the correct setting”.