NAD C 658 DAC

Yes I own it, and you can read some stuff in this thread I started

https://forum.audiogon.com/discussions/does-this-exist-preamp-streamer-dac-with-mqa-roon-and-more

In general I was not originally pleased with the performance of the C658. But after 200+ hours of burn in, it definitely is sounding better than it started. I used to own the PS Audio DirectStream Jr (recently discontinued) and it sounded far better than the NAD. It's not a proper preamp, however, whereas the NAD is, so it's not an apples to apples comparison. It also costs a lot more. I don't have any experience with Mytek to compare them. 

Dirac still hasn't been implemented in the C658 yet, so that may be the killer app that makes it sound a lot better. I wish they would hurry up with the Dirac firmware update. At this point I'm still planning to return mine but I am hoping to give it a fair shake by trying Dirac first. In my particular case, I'd rather up my budget and get more performance. The NAD has a killer feature set, but with Dirac 2 months late already and the sound quality not super impressive, it's been fairly underwhelming. Over on AVSForum there are a few people that have said they are happy with it and a few who were not and already returned it.

As far as which chip it uses, I'm not sure but I believe someone on AVS Forum posted something about that after inquiring with NAD. I don't pay too much attention to that since the chip is only one part (and not even the greatest part, IMO) in dictating the overall sound quality.

jnehma1....Thanks for your input. I could have sworn the I saw the PS Audio DirectStream JR last week on their website so that seems very recent they discontinued that model. I really don’t need a preamp as I have tube preamp I’m very happy with. It was all the functions that intrigued me as well as the BluOS service available. I’m getting into Roon and will have that on a separate Mac Mini but liked that fact that if I wanted to loose the Roon part I could run my Tidal "locally" on the C658. The Phono input is a plus for me too as I’m trying to consolidate and my vinyl setup is not my priority at the moment. The Dirac feature I will take as Christmas coming early...not getting my hopes up. Do you feel it’s the preamp that is the weak link in the unit ?

@zipiv I kind of feel like it's the DAC but it's hard to say for sure. When I had the DSJr I ran it through a Marantz receiver as a preamp and that combo sounded way better than the NAD. Obviously a Marantz receiver isn't going to be the greatest preamp either but it was still no contest.

The DSJr was just discontinued recently. You can still get to it on the PS Audio website but there is no button to buy one. There is also a forum post saying they will be redesigning it and re-releasing a new DSJr in the future, but that will be after the cost-no-object super DAC they are working on so I wouldn't hold your breath.

I use Roon but you can run Tidal to the DSJr using the free MConnect app from a phone/tablet so you don't really need BluOS for that.

If you are happy with your tube preamp and going to hold onto it, I would look at something else other than the C658. I don't know what your budget is but the PS Audio was far superior as a streamer/DAC (far more expensive too). I've seen some people post that the NAD doesn't really sound any better than a Node 2i if using both as just streamer/DACs. You can get one of those for 1/3rd the price and pair it with your nice preamp. Again, the caveat being Dirac could change everything...