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.

@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...

@rockaddict I don't have experience with those amps but since it's clear you are considering using Class D amps, why not consider the NAD M10? It does everything the C 658 does and has built in Hypex amplification for $1k more (plus other features like a color touchscreen display, etc). Dirac is already available for the M10.

@rockaddict I'm not sure you have that info correct about the M10. First off, it's an integrated amp so you don't need to buy an external amp. That's why I suggested it because the C658 plus an amp could easily cost more than the M10 which has an amp built in. And from what I'm seeing online, the M10 costs GBP 2,100.

@rockaddict Sorry about your blip, whatever it may be. Arcam has recently announced the SA-30 which is just like the M10 -- an integrated amp (class G amplification), DAC, preamp, with room control, MQA support, and Roon endpoint. No pricing announced yet and it doesn't come out until the fall, but I think Arcam prices are more favorable in the UK than comparative US prices. Good luck!