Ok, I've put about 200 hours on this DAC now, and have had the opportunity to have a decent listen to it.
These impressions are via speakers and are not ideal, as I have only just set up my gear in a new house and new dedicated listening room. The room is quite 'live' and needs some treatment to tame a bit of mild slap echo.
That said, I'm VERY happy with the sonic signature of this DAC. Detail retrieval is excellent without becoming etched and artificial, and the tonality and timbral reproduction ain't half bad either. The sound is entirely believable. I do think that I subjectively prefer the PCM1704UK DACs in this regard (particularly with string-based instruments and pianos for example) but the NFB-3(2014) has better detail retrieval than the Reference 5, DAC3SE and DAC19DSP that I've previously owned, and certainly more than the original NFB-3 that I owned, so this is where it edges ahead. I guess you can't have your cake and eat it too, not at this price point anyway! These impressions are all based upon my audio memory, and should be taken with a grain of salt until I have the chance to compare this DAC back-to-back with a PCM1704UK-equipped example.
Sound staging is also very good, but the very slight reverb in my existing room configuration is hindering sound staging I feel. I've achieved better imaging from this same gear (albeit with the onboard SB Touch DAC) in my old house, and I've tested the same configuration in the new room and achieved worse results. Given that the NFB-3(2014) trumps the onboard SBT DAC based upon my comparisons, I can't wait to improve the acoustics of the room (adding some room treatments and soft furnishings) to really let this gear shine.
The USB32 works flawlessly with the Squeezebox Touch. I applied tape to the +5V pin as the USB32 is internally powered, and some members have reported sonic improvments when severing the +5V connection.
I ordered the DIR9001 SPDIF receiver board as well as the WM8805. The DIR9001 sounds more like the USB32, whereas the WM8805 is a bit more laid back, smoother and a tad warmer. I look forward to experimenting with these SPDIF boards in future.
The new casework is a marked improvement over the older NFB-2/3 DACs. It is thinner than the kind used on the Reference 5 etc, but is still much better than the pressed steel casing on these earlier models. The recessed screws are a nice touch, although one of mine had a slightly stripped head from the factory, and this made removal a real pain. The input selector knob on the front panel is also slightly askew. I will try to adjust this, but I am likely to be at the mercy of the knob and splines on the switch itself.
In addition to the free TCXO upgrade and the optional OCC wire upgrade, I had the ACSS outputs replaced with RCA outputs, as I have no intention of going 'all audio-gd' in my system, so these connections are unwarranted. The RCA jacks are all nice CMC branded items.
Compared to my former Resonessence Labs Concero, the audio-gd is slightly more resolving and has slightly wider sound stage. In terms of overall tonality, they are pretty similar I feel. They are not bare-boned detail freaks - they have soul. I could easily live with either of these DACs, and it just goes to show how good the Concero is. It packs a mighty punch into a tiny package!
Overall, I consider this DAC to be brilliant bang for buck, and a worthwhile upgrade over the old NFB-3 with the dual WM8741s.
I hope that I can tee up a get-together with my friend John Darko (of digitalaudioreview fame) to undertake some back-to-back comparisons on his rig against some highly fancied (and priced!) DACs.