NAD C658 Streaming DAC Review

[AndrewDavis]

I appreciate that the panther is observing social distancing by working alone. When will he get a N95 mask and some hand sanitizer?

 

[amirm]

I appreciate that the panther is observing social distancing by working alone. When will he get a N95 mask and some hand sanitizer?

He has already. The mask is on its head which is not in the picture....

 

[thefsb]

OK manufacturers, what we need here is a combination of:
-Build quality and HT Bypass implementation of the Parasound P6
-Feature set combination of the MiniDSP SHD and NAD 658
Is that too much to ask?

It would seem so.

I would also like to have a HDMI audio extracton feature, i.e. HDMI pass thru connectors.

 

[EB1000]

Does the SHD have an effective Home theater Bypass, that can be selected with one mouse click?

No. That's why I chose the C658.

 

[ex audiophile]

OK manufacturers, what we need here is a combination of:
-Build quality and HT Bypass implementation of the Parasound P6
-Feature set combination of the MiniDSP SHD and NAD 658
Is that too much to ask?

I wonder about the P6 as well. I just sold mine, partly because of the poor performance of another Parasound component tested by Amir but mostly because it lacked room eq. I was able to compare the P6 to my STR preamp (same amp/speakers/room in both cases) and at moderately high volumes (>75) there was a dramatic difference in SQ. The difference was far less when I turned off ARC in the STR, so I believe that was the major factor. The STR is about double the cost so I'm not criticizing the P6 so much as pointing out the value of room eq. For me it is now an essential feature.

 

[fricc]

This is a review and detailed measurements of the NAD C658 streamer and DAC...

I have one, I bought it "refurbished" as well. I have been using it with my Apple TV and Mac mini with the HDMI adapter module. It is connected to a pair of B&O Beolab 18 speakers and a Beolab 19 subwoofer.

I have done my own measurements a while ago using REW and my trusty old EMU 0204 and I had pretty much the same results, which — btw — also precisely match what @amirm saw with the Bluesound NODE 2i Streamer: same jumpy digital inputs (yes, the HDMI module is the same as the toslink input). Playing from Roon, at -5 dBFS I get some 96dB SINAD, at 0dB it drops to a bit less than 90dB. I have also measured the bluetooth connection, lots of distortion. The AirPlay input instead works very nice, and gets pretty much the same results as with Roon streaming.

Measurements aside, it actually works pretty darn well and it sounds just fine. I haven't heard any pops or clicks, the HDMI switching is fast, the subwoofer channel works great (I don't know what people out there have been doing), bass management works well and Dirac room calibration is great. I also use the phono input with my vintage Thorens turntable and Shure V15V cartridge. It sounds very nice. I haven't bothered measuring the phono input, but I'm pretty sure it exceeds the SINAD of the turntable + vinyl records.

With 96dB of SINAD this unit will reproduce well any CD quality source. HIRES sources are definitively wasted on it, although a 24bit signal seemed to have a bit less distortion than a 16bit dithered input (generated with REW, played through Roon).

In my case I think that the limit in my sound chain is not in the streamer, but most likely in the speakers. The B&O Beolab 18 DSP runs at 48kHz/24bits and if I feed them with the analog signal from the NAD they will reconvert it to digital and process it internally all over again. I'm pretty sure that the B&O's internal processing is not going to surpass that of the NAD.

As for the price, it doesn't sound excessive to me. I haven't seen any other streamer out there that has all the features of the NAD C658 (HDMI, Phono, Dirac, Roon), and/or that measures appreciably better at the price point.

If any of you find something better, please let me know, meanwhile I'll enjoy my unit as much as I can

 

[Spocko]

That looks great if it works. With all the complaints and problems with the c658 (threads on several forums), I think I’d be inclined to go with an Anthem STR integrated over the M33 and buy a separate network streamer.

Good point. Node 2i appears to be the way to go as a streaming source too

 

[Spocko]

OK manufacturers, what we need here is a combination of:
-Build quality and HT Bypass implementation of the Parasound P6
-Feature set combination of the MiniDSP SHD and NAD 658
Is that too much to ask?

Sounds like Anthem should upgrade its STR preamp to include these features (and eARC please for those now eschewing AVR)!

 

[capt.s]

No. That's why I chose the C658.

Just to clarify for those interested specifically in HT bypass - The C658 doesn't have a direct HT Bypass either. Both the SHD and C658 have 'analogue' inputs that can be 'kind of' used for that purpose with the C658 having the advantage of being able to assign a fix volume output. So apart from the C658 not requiring you to set the volume to a particular level to match your AVR's calibration there's no difference. They both go through an unnecessary AD/DA conversion and there's no pass through for the subwoofer either. The Parasound HT Bypass is a direct analogue pass-through for L, R and Sub.

 

[fricc]

Just to clarify for those interested specifically in HT bypass - The C658 doesn't have a direct HT Bypass either. Both the SHD and C658 have 'analogue' inputs that can be 'kind of' used for that purpose with the C658 having the advantage of being able to assign a fix volume output. So apart from the C658 not requiring you to set the volume to a particular level to match your AVR's calibration there's no difference. They both go through an unnecessary AD/DA conversion and there's no pass through for the subwoofer either. The Parasound HT Bypass is a direct analogue pass-through for L, R and Sub.

The C658 is a fully digital device, everything happens in the digital domain.

 

[capt.s]

Not fully as you suggest. The analogue RCA inputs are converted to digital, processed to some degree if only for volume, and converted back to analog out to the power amp of your choice.

 

[fricc]

Not fully as you suggest. The analogue RCA inputs are converted to digital, processed to some degree if only for volume, and converted back to analog out to the power amp of your choice.

Yes, that is exactly what I mean

 

[KarVi71]

I also own this device and I'm quite happy with it.

I know many peoble have had their share of problems with the unit, but in my daily use it has been rather good up until now

I find the sound quality to be really good (excellent actually), and Dirac does wonders for the sound in my room.

The Dirac integration is very good, with memory for 5 different settings you can switch between to compare different sound settings / curves.

I mostly use it to stream local content (from my NAS) and Tidal, and that part works extremely well I think.

I use the built in RIAA and it also sounds good.

I also sometimes use the Bluetooth connection (mostly for podcast, from my phone), and find it to be completely trouble free, and the sound quality is good, for what it is.

So I am sad, but not terribly surprised, to see that it measures so badly.

Still this is the only device of its kind in existence (AFAIK), and looking at its feature set, the price is reasonable if a little to the high side.

If only it measured better ...

All my positives aside, its extremely sad that this device is so plagued by firmware errors, and that they are so slow to fix them. This is a relatively high price device, and one would expect better service from a well known manufacturer as NAD.

This is hurting their sales for sure, peoble will read the threads with the many problems, and stay away from it. And Nad can only thank themselves for this. This product had a chance to really shine but as it is, it only does so momentarily.

 

[bluefuzz]

So I am sad, but not terribly surprised, to see that it measures so badly.

Well, as Amir pointed out, it measures better than spec. And as we all know, even this mediocre performance is well beyond the capabilities of human hearing to actually hear any problem with ...

its extremely sad that this device is so plagued by firmware errors, and that they are so slow to fix them.

As I've said elsewhere, I think NAD/Bluesound's problem with these devices is that they base their OS/firmware on an open source Linux but then choose to make BluOS proprietary and closed source. So they are reliant on 3rd parties for much of the upstream code but can't benefit from the wider community to help fix bugs that may appear.

 

[KarVi71]

Well, as Amir pointed out, it measures better than spec. And as we all know, even this mediocre performance is well beyond the capabilities of human hearing to actually hear any problem with ...

I understand, and agree with that.

Still, good measurements point towards good and thoughtfull design, and at this price they should be better than just average.

As I've said elsewhere, I think NAD/Bluesound's problem with these devices is that they base their OS/firmware on an open source Linux but then choose to make BluOS proprietary and closed source. So they are reliant on 3rd parties for much of the upstream code but can't benefit from the wider community to help fix bugs that may appear.

That is probably true. But I think that making it open source or something to that extend, would make it harder for them to control the direction of the development?

Its still problematic, and there are probably a lot of challenges for a software team like theirs.
Software development and refinement is not cheap.

I am still very happy with my C658, and hope they can fix the problems with it over time.

 

[Alexanderc]

I had been considering purchasing a c658. For me, it measures well enough and checks all the functionality boxes, but I’m concerned about the popping sounds (from not being able to lock on to an incoming signal?). Should one assume that this is the case on every single unit, or could it be poor QC? If I were to go to my local dealer and listen to one, would I hear the problem? Would it be obvious right away, or do these issues take a while to surface?

 

[SIY]

I had been considering purchasing a c658. For me, it measures well enough and checks all the functionality boxes, but I’m concerned about the popping sounds (from not being able to lock on to an incoming signal?). Should one assume that this is the case on every single unit, or could it be poor QC? If I were to go to my local dealer and listen to one, would I hear the problem? Would it be obvious right away, or do these issues take a while to surface?

Try this: generate a test tone file, somewhere in the midrange. 400-1000 Hz or so. Now feed it into the optical or coax input of the C658 and listen. This makes it very easy to hear the problem if it exists there.

 

[bluefuzz]

Still, good measurements point towards good and thoughtfull design, and at this price they should be better than just average.

Yes, agreed.

But I think that making it open source or something to that extend, would make it harder for them to control the direction of the development?

They would still be in control of what gets into official release builds. Probably the main reason it's not open source is that services like Spotify, Tidal and Dirac – not to mention the rights holders of the music they distribute – get a bit jumpy when around open source projects. All those nasty hacker types poking their noses where they've no business to ...

I am still very happy with my C658

As am I. It sounds great and all its features work as advertised.

 

[ex audiophile]

Sounds like Anthem should upgrade its STR preamp to include these features (and eARC please for those now eschewing AVR)!

Exactly what "features" are your referring to? I have owned all three of these components (STR pre/NAD/P6); I returned the NAD for malfunctions and sold the P6 for lack of room correction. The STR is not going anywhere because of its superb performance and excellent feature set. It isn't a realistic comparison in any case because the STR retails for more than twice the cost of the others. The build quality of the STR is in another league altogether, it has balanced independent sub outs, superb HT bypass, and a more advanced version of ARC that will phase match your subs to the mains. Granted it does not have a built in streamer but that allows the user to choose whatever interface (Yamaha, Denon, Sonos, whatever) they prefer for digital input. I've used all of the major interfaces and settled on Sonos as the most stable and easy to use so I chose a Sonos Port to input my streaming music. The STR has been thoroughly measured at Audioholics with this conclusion "I'm so impressed with how the Anthem STR separates components work in my reference system that I've decided to make them a permanent fixture." Also measured by hometheaterhifi.com with excellent results.

 

[bluefuzz]

but I’m concerned about the popping sounds

I experienced some light popping sounds at first after sitting idle for 20 minutes or so. But it seems to have stopped that in the last month or so.

If I were to go to my local dealer and listen to one, would I hear the problem? Would it be obvious right away, or do these issues take a while to surface?

I'm pretty certain the popping is a software problem - possibly an upstream kernel bug or similar - and maybe only affecting certain combinations of features being in use. I.e. it probably affects all units but only in certain situations and it will almost certainly get fixed in time, if it hasn't already ...