Why USB to SPDIF and not optical?

"XP generally upscales 44.1 files to 48 unless special drives are installed."

Not true. My USB converter uses the native drivers and it outputs 44.1 on XP. There are several ways to avoid kmixer, including:

1) unmapping the device
2) Kernel Streaming
3) ASIO

Steve N.
Empirical Audio

Steve - Let me re-phrase - "XP generally upscales 44.1 files to 48 unless special software is installed to bypasses the XP upscaling". You are correct that is not only a driver issue. Unfortunately the simple solution of unmapping the device often disables the device so it is not a general solution - at least for me The specific issue I was addressing is whether the Bel Canto managed to bypass this upconversion. If there is no additional software other than the native drives, I would suspect that the upconversion still happens. Do you concur? Does your converter get 44.1 out of iTunes? As I understand it, neither KS or ASIO is available for iTunes. If that is incorrect I would love to know a general process for bypassing the upconversion when using iTunes. I like the iTunes interface, but am frustrated by the uponversion. Any insight would be appreciated.

"If there is no additional software other than the native drivers, I would suspect that the upconversion still happens. Do you concur? Does your converter get 44.1 out of iTunes?"

No, not with Vista and my converter. It changes 16/44.1 into 24/44.1, so Vista is bit-perfect.

With XP, there is something changed if you dont use Kernel Streaming, but it is not necessarily 44.1 to 48. I believe there is volume adjustment DSP, just like Vista does with 16-bit data.

I dont recommend using iTunes on any PC with any device, even WiFi. Use Mac with iTunes.

Have you tried Jriver?

Steve N.
Empirical Audio

I just installed J River Media Center 13 last night and am still getting 48 MHz output on XP. I installed ASIO4ALL and upconversion still happens. I still need to do some experimenting to be sure I have everything set up correctly. Do you get 16/44.1 out of J River? If I read your comment correctly Vista converts 16/44.1 to 24/44.1, so I would not call that bit-perfect. Is your software adding the bits or is Vista? The purist in me would still like to get the original 16/44.1 out to my DAC without the any changes happening in the PC. I sometimes feel like I am losing the battle with this. Might try foobar next, but I am not sure I can live with the interface. Thanks for your help.