Hi Raife,
I'll have a go:
In essence Naim has three digital lines: Servers; Streamers & DACs.
Servers
These will:
1. Rip your CDs, locally or remotely;
2. Serve up an uPNP music stream;
3. Give you an Internet Radio; and
4. Render your remote/local files to spdif for feeding a DAC.
In the case of the NSxx and HDX the servers also have an onboard DAC, meaning that they can output what they are rendering into a pre-amp.
Streamers
Really these are renderers, they will:
1. Consume a uPNP data stream and feed the output via SPDIF into a DAC; and
2. Give you an Internet Radio
In addition they have an onboard DAC, so they can be plugged direct into a pre-amp.
DACs
There is one, which can be viewed as three, that is:
1. Bare nDAC;
2. nDAC + XPS; and
3. nDAC + PS555.
As to your options:
Do some searches, or look at some of the current threads, and you'll see a wide range of opinions.
My personal advice would be to get to a dealer and have a listen.
I would agree with a number of people here that the nDAC is the VFM product in the range, and very easy, if not cheap, to upgrade.
M
