[DS-21]

***I actually suspect the d3020 has a Hypex UCD-based amplifier,***

Looks like you're right on that one.

Does anyone have "guts" pics? I wonder if it's a bespoke module, or two UcD180's with an undersized PS.

[srb]

According to the hifi.nl review of the NAD D 3020 it uses a Hypex module.  If that is true, at 30W/ch it could possibly be the Hypex UCD32OEM 30W/ch stereo module or something very similar.

Steve

[DS-21]

Maybe a bespoke beefed up version of that one? The 30W/ch rating of the UcD32OEM is into 4Ω loads, and NAD claims 30W/ch/8Ω, 60W/ch/8Ω.

At the price, twin UcD180s would be a (pleasant) surprise.

[EuroDriver]

I finally bought a D3020 and I am floored !  Sounds great as I said in my earlier post, but to my surprise I got it to play 24 bit 192 KHz FLAC using Foobar (win XP) with a USB 2 driver from T + A  website

http://www.taelektroakustik.de/index.php?id=521&L=1

The sound quality playing a Channel Recordings Studio Master is an absolute joy

One further tip, is to try out your D3020 on your old speakers first, you may be very pleasantly surprised by how much your speakers sound.  My Canton Karat 720.2 sound much better than I ever thought they could.  The Hypex amp handles difficult speaker loads very well

[ashok]

I finally bought a D3020 and I am floored !  Sounds great as I said in my earlier post, but to my surprise I got it to play 24 bit 192 KHz FLAC using Foobar (win XP) with a USB 2 driver from T + A  website

To clarify, did you install the driver in your computer and connect the computer's USB port to the USB input in the NAD? May I ask how you verified that your computer was not internally downsampling the 192kHz to 96kHz?

Thank you!

[EuroDriver]

To clarify, did you install the driver in your computer and connect the computer's USB port to the USB input in the NAD? May I ask how you verified that your computer was not internally downsampling the 192kHz to 96kHz?

Thank you!

I installed the T + A USB 2 driver software several weeks ago and used Foobar to play FLAC files to my T + A DAC 8.  Unfortunately I did not look in the Foobar configuration to see which output driver / software the being used.  Last night did the NAD USB driver software install, connected the D3020 and immediately ran Foobar.

I picked a 24/192 FLAC file, and it sounded great.  This morning when I got up, I found that Foobar had locked up trying to play the JPEG of the cover art.  So I restarted Foobar and to my great surprise I got the error message window sample rate not supported.   After 20 minutes of fooling around I final changed the output module selection to DS - USB Audio, and Foobar would play the 24/192 file with no problem

I have also been wondering if Direct Sound could be down sampling the WAV file to 96 KHz.  Looking at the function set of Direct Sound it does not seem that sample rate conversion is one of them.
http://msdn.microsoft.com/en-us/library/ee418868(v=vs.85).aspx

At the output end of Kmix the GFI filter might be cahnging the sample rate
http://msdn.microsoft.com/en-us/library/windows/hardware/ff537047(v=vs.85).aspx

Also what I don't know is does the T + A driver software use Direct Sound. 

This evening I set up my system again, but now the output module name has changed from [DS- USB Audio] to [DS - NAD USB Audio].  The NAD Output module which I think I was running this morning seems to have disappeared.  Instead there is a output module labelled [ASIO: NAD USB Audio ASIO Driver] but it does not work giving the error message "Unrecoverable playback error: Could not initialize the driver".  I did quite a bit of fooling around this lunch time ad that seems to have changed the driver installations.

The D3020 is supposed to accept 24/192 Khz on the Coax SPDIF input, so the DAC has the capabilty.  Any decent modern USB receiver chip should be able to accept USB 2 data rates, so then it just a matter of the USB driver.

The much more expensive D7050 has the same sample rate limitation and the same driver as the D3020, which I also find surprising.  May be NAD were not happy with the consistency of 24/192 playback, so they have disabled it for the present time ?

I am very much an amatuer on this stuff, appreciate your insights

[ashok]

I found this picture at CNET.



It appears that the D3020 is capable of only 24/96 on USB and that D7050 and D1050 are both capable of 24/192 on USB.

But if you go to NAD's website and look at the specs for the D7050, it clearly says 24/96 on USB. Only the D1050 USB DAC is capable of 24/192 on USB.

So, there is some confusion. It does seem a little strange that NAD would restrict the D3020 and D7050 to 24/96 on USB.

I am planning to get a D3020, and will test out its USB input.

[EuroDriver]

I did some tests with a Cambridge Audio DAC Magic which is Max 24/96

With Direct Sound receiving a 24/192 feed from Foobar, DS down sampled to 44.1 kHz

For some reason my DAc Magic did not want / could not play 24/96 !

[srb]

If the DAC hardware does not support Direct Sound or hardware mixing, then the stream will be routed through Windows KMixer and downsample.  Try ASIO or Kernel Streaming drivers for Windows XP through Windows 8 and you can additionally try the WASAPI driver for Windows Vista through Windows 8 to bypass KMixer.

If you are successfully bypassing the Windows KMixer, then the Windows volume control should not have any effect, and your DAC(s) should be able to receive native bit-perfect streams up to their maximum resolution.

Steve