I'll do my best to answer these as I can currently - and will add on as I gain experience. You'll also see I'm posting about both my DirectStream DAC and this NT-503 in other threads.
Quote:First, how easy is it to use?
Surprisingly easy - just using the front control panel, it took me all of 30 seconds to get it turned on, dialed in to Network, then stream to it using the Teac AV app. I poked through a settings and filters a bit, then broke out the manual to see what the descriptions of the filters were, and poked at it some more. Connected my Roon streaming PC directly to it and had it running that way in about 60 seconds after checking settings, and making sure Roon could see the DAC via USB. Super Easy.
Quote:Second, is the app straight forward and how is the SQ of PCM/DSD upsampling?
The app is a little clunky, but works. I find the Roon software so much easier and more intuitive, but the TEAC software will do fine if you don't mind the clunkiness and don't have another software option.
As for UpSampling - I'm still playing with that. The higher up you can sample, the smoother the music seems to get - but I'm not hearing a huge improvement like I was hoping. It's not a bad thing - it's just the differences between native input and upsampled aren't huge. Again, I still need time with this...when the changes are subtle, and there are so many variables, I need to take it step by step, getting used to how it sounds, then changing one settings, and getting a feel for the differences. So far, the upsampling just makes everything a little more analog sounding...which is what I was expecting.
Quote:Third, what would be the best SQ cable input choice for connecting a CD player/transport to the NT-503?
Since it's unlikely that your CD has USB out (do any of them?) I would say digital CoAx. Optical has it's own issues that are inherent in design of the format - so I shy away from it - too much jitter. Make sure you're using a CoAx cable that's *made* for digital transport, and don't just plug in any RCA cable you have around. Any decent RCA cable will work, but digital needs specific impedance requirements and other such things to not cause jitter which would make the DAC work harder. I've literally heard a truly nice CoAx cable appear to make a DAC sound *louder*, simply because it was able to get those bits down the pipe more accurately. I wouldn't have believed it if I didn't hear it for myself. I used to think "Bits are Bits", but there is way more to audio bits than there are computer bits.
Quote:I have a large collection of CD's but I'm primarily interested in this unit for high resolution WiFi streaming.
How were you thinking about doing this? If you were thinking about Bluetooth - I'm unsure of what bandwidth Bluetooth can support (off the top of my head) and what jitter it might introduce. In fact, now that I'm thinking about it, I know I saw a chart on the TEAC page that listed what the inputs were capable of...I'll see if I can find that for the Bluetooth input.