How to install the Windows driver for DirectStream, PWD MKII, NuWave and NPC

Written by Paul McGowan

Setting up on a Windows Computer requires the installation of our USB driver available for free download here. These instructions apply to the PerfectWave DAC MKII, the NuWave DAC, DirectStream DAC and NPC Phono Converter.

Connect the DAC or NPC to your computer via USB

Once you have downloaded the driver, but before you install the driver, connect the device to the computer's USB input and make sure USB is enabled. With the device powered on, connected to the computer through a USB cable not to exceed 5 meters in length, (5 meters is generally accepted as the maximum length for a USB cable but we would recommend something a lot shorter to be safe and yes, the quality of the USB cable matters a lot to the sound quality. Don't cheap out) install the driver on your computer. Properly installed, the driver and device are now communicating with each other successfully.

Specific to the NPC

It will now be necessary to setup the sample rate and bit depth for the NPC. The computer is now the master, the NPC the slave, and will control the NPC when USB is enabled. Open the computer's Control Panel. From the Control Panel open Hardware and Sound. From the Hardware and Sound menu open Sound> Manage Audio Devices. From the Manage Audio Devices menu, select the Recording Tab. From the Recording tab menu select Properties. You should see Line PS Audio NuWave Phono as one of the devices. Select the NPC. Then select properties. From the Properties menu select Advanced. If you have PCM selected on the NPC as the audio format you wish to use, the format select window in the Advanced Properties window drop down menu will display the available sample rates and bit depths to choose from. Using the drop down box as in the picture, select an acceptable sample rate between 44.1kHz and 192kHz. We recommend for most users 96kHz and nothing higher. As previously explained, 96kHz provides full bandwidth for any LP or, for that matter, anything most people are likely to want to play. Using 96kHz and below engages the best sounding decimation filters in the NPC and provides a near perfect zero group delay for PCM users. 96kHz gives full bandwidth to 48kHz, exceeding the threshold of human hearing by twice (and vinyl LP's don't exceed 30kHz even under the best circumstances), and maintaining perfect phase relations within the audible band. Exceeding 96kHz is fine, but unless you have a good reason to do so and need the extended bandwidth of up to 80kHz, not recommended for best sound. Once selected, the sample rate will appear on the NPC screen. If you have DSD selected on the NPC as the audio format you wish to use, the format select window in the Windows Advanced Properties screen will display only two available sample rates: 176.4kHz and 352.8kHz. Choosing 176kHz will net Standard DSD rate and choosing 352.8kHz will result in Double Rate DSD being selected. The choice you make will be displayed on the NPC front panel display window. The Windows volume control must be set to 100 for DSD to work It is instructive to remember that DSD will be sent using the DoP (Digital over PCM) format which while compatible with any computer or DAC that can accept PCM data, you cannot playback DSD data without installing a program that supports DSD. JRiver and Foobar are two good examples of programs that will playback DSD over DoP. Once setup it is useful to test the connection and make sure everything is working properly. Use the PCM format mode on the NPC (see above for instructions how to select PCM). If you do not yet have your turntable connected to the NPC it may be convenient to simply use an iPhone or iPod to feed the Analog Inputs (not the Phono inputs) for this test. Set the output level of the device to maximum, connect a 3.5mm male to dual RCA connecting cable and start playing music on the mobile device. In the Properties menu of the Recording tab you will see a graphic representation of a VU meter next to the NPC and this should show music playing if everything is setup properly. If your computer monitor speakers are on, you should hear the music playing. If you hear no sound it may be necessary to reboot your computer and follow the setup procedure again. Once you have verified everything is playing properly use any recording program, such as Audacity, as you wish. Instructions on the use of Audacity or other similar recording programs are beyond the scope of this manual. Please refer to the owner's manual of the recording program you're using for further instructions.
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