NAD C 658 DAC

The C658 has appeared on my radar as well.

I have a "classic" NAD 7025PE Receiver that is presently serving as my Pre-Amp.  In the past, I was impressed with "the little receiver that COULD...."  But now, I am seeking something to move the audible performance up a few notches

I am looking for a new "Pre-Amp" for around $1500 and am running a set of ELAC UB5s on stands and a Goldenear ForceField Amplified Sub. With an Emotiva XPS-2 and the Amped-Sub, I should have Power to spare.  My setup is in a Living Room and has to contend with Speaker Placement limitations and furniture.  It sounds like the C658 with Dirac could be a great tool for making my gear "sing in harmony".

However - one thing that seems to REALLY surprise me is the lack of good information from users (like on U-Toob). It almost makes me wonder if Web-Based information on this unit has been "Sanitized". Usually, a piece of gear like this would tend to generate more "buzz", but my impression is that the unit fell short of expectations and/or reviewers are waiting to see it implemented WITH Dirac.

I suspect that NAD got into some problems with the software and/or legal wrangling with Dirac that threw the product delivery schedule out-of-whack (Dirac was a feature that was somewhat touted from the beginning, but seems to have only recently materialized [AND at additional cost...] in any serious form). Or maybe NAD released it a bit prematurely before they had the details hashed-out with Dirac. I wonder if any semi-serious reviews will be published soon, highlighting the use of Dirac and Dirac-Live in conjunction with it.

@geeqner  Just to confirm that the basic version of Dirac is free.  On another forum, most posters are happy with the difference it makes but a few have shelled out for the paid-for version and are also happy.  I've not checked the details but I've seen chatter about a further version of Dirac being in the works, one that deals with subwoofers.

All things being equal, my demo (C 658) is tomorrow....

@rockaddict19 - Let us know how it works out / what your initial impressions are.

The only other thing that makes me a tad leery of the C658 is that it does ALL of the pre-amp / source selection functions in the DIGITAL domain. I TRY to not be an "Analog Snob" but unless the DSP and D-to-A and A-to-D is really "cutting edge", I worry that the sound quality will suffer and whether it will really be an "upgrade" from what I am using now (or not)? It SUPPOSEDLY shares a lot of the tech used within the Masters M10/M12 products, but to WHAT degree?. It would have been "cool" to see an "Analog Bypass" mode built into the C658.

[My NAD 7225PE Receiver that is presently serving "Pre-Amp" duty was a nice, solid little unit - but it is probably past it’s prime and I believe it to be the Weak Link in my current system (but I could be wrong)...]

But then again, in my less-than-optimal listening room (Living Room) the benefits of Dirac and fresh (NEW) electronics may outweigh any penalty incurred. The other options (at least, the current Front-Runners) in my research are the Emotiva XSP-1 (fully-balanced Analog WITH built-in Sub Management) and PS Audio Stellar Gain Cell / DACT or perhaps a gently-used 2-channel HIGH-End Pre if I can get a good deal on one. If I go with the NAD, I could probably offset part of its cost by selling my Node 2i.

Also - Anybody know what the C568 is running for a PROCESSOR "under the hood".  It's one thing to have good A-->D & D-->A Converters, but if the thing is going to run Dirac / apply EQ Curves and Timing Algorithms generated externally by Dirac - the thing needs some relatively high "processing horsepower" and Memory.

Another option that I had not considered before, but now also appears to be a possibly good solution would be to pick-up a used / re-furb Emotiva XMC-1 in a 2.1 setup. 

Although it was designed primarily for HT (which may normally be considered a "no-no" in Audiophile circles), it probably has superior  processing and A-D / D-A capabilities [It sounds lie a multi-processor BEAST] with features including:

-MAIN PROCESSOR: TI AM-1808 Sitara Arm9 32 bit 375MHz 
-24/192k Burr Brown DSD1796 main zone DACs.
-Has fully balanced circuitry for the L&R Front Channels
-Can probably be had for less than a new NAD Unit

Well, I post with just a little trepidation! The demo went ahead but the outcome was close to being as unexpected as could be imagined in hi-fi terms.

In short, I didn’t get the NAD C 658. The search for a new amp setup was because I *thought* there was an issue with my current Rotel RA-1572 integrated with the bottom end disappearing when playing busy/dense music (and a couple of other more minor events). However... post follows mainly about the demo but there is a bit about comparing the SQ of the Rotel and the NAD C658.

I took the Rotel to the demo with the intention of showing the store the "problem" ((same store as original purchase). Except.... the "problem" didn’t reproduce with other speakers. I tried 3 amp setups: the Rotel on its own; the Rotel as a pre-amp with a NAD C 268 as a power amp and, finally, the full NAD combo (C 658 + C 268). With each set up, I tried different speakers. Imagine by full on surprise when each amp set up sounded broadly similar with every speaker. Of course, if the Rotel on its own had the "problem" identified, it would have sounded markedly different. That’s when the penny dropped that the problem was far more likely to be my current speakers. Slightly embarrassingly, a couple of people had asked whether that was the issue (crossover points etc). Blithely, I had cast it aside.... "No, no; it’s the amp" was my earnest and now obviously inaccurate reply. Sometimes, the Homer Simpson moment just hits home. Doh!

So, having gone in with real intent and fully expecting to walk out with a gleaming new NAD C 658, I did indeed indulge. In a pair of Monitor Audio Gold 100 G5 speakers :o) (is there a "scratch head" emoji?). In short, the "problem" with the Rotel doesn’t reproduce with either the MA Golds, nor the KEF R3s which I also demoed. I preferred the MAs because, to my ears, they were a fraction tamer than the KEFs although the latter may well work well with the NAD for the reasons below.

The NAD C 658 is obviously feature rich compared to the Rotel, so that’s a gimme. However, on the off chance it’s of interest to at least someone, here’s my take on the SQ comparison. On a same speaker basis, the audio characteristics of the amps are much more comparable than I expected. If anything, the Rotel offers marginally more detail and the lower frequencies are marginally rounder. Higher frequencies are very similar and I couldn’t detect and significant differences with mids. Drums and percussion have slightly more depth with the Rotel. In truth, if anyone had dropped in without knowing which equipment was being used, I think most would have been hard pressed to hear significant differences without an extended listen. Overall, the NAD is slightly more restrained (not to say it is restrained), hence it being arguable that the KEFs will not sound too "zingy" with the NAD.

In short, if I had specifically wanted streaming and/or room correction and didn’t already have an amp, I would *probably* have gone for the NAD. The NAD is a touch more expensive than the Rotel although, of course, the NAD will also need a power amp which will add to the overall cost. On purely SQ? I’ll sit on the fence and put it down to personal preference... :-) .

To those already with the NAD and those who eventually pull the "buy" trigger, good luck and happy listening.