Review: NAD m51 DA converter

Category: Digital

*Musical tastes: Pink Floyd, Miles Davis, Harry Connick
*Aspects of sound: I like clarity and space with good timber and no glare
*Worst thing system can do: shrill or bright

*How long has piece been in system: 2 days (running non stop)
*What did it replace: Rega Apollo R CD player
*How didn't the sound change: it was less brittle on the top end, the soundstage was clearer and more defined as well as deeper and wider, and the music sounded more musical.

*Stengths: the ability to make you not think of the equipment. Tranparency and openness
*Weaknesses: not anything I can put my finger on right now
*If money was no object: I would still own it, but I would spend thousands on a great vinyl set up.

The review:

I'm not a great writer so please bear with me.

I've basically have put together a new hi ended (modest by some standards) in the last 3 months. My old system was a CJ MF2100 amp, Acurus LS11 preamp, Calfornia Audio Labs DX1 CDP and Vandersteen 2ce speakers. I still like this system a lot and it had no great faults, but ultimately I yearned for detail and dynamic range. Thus the new system. One thing you must keep in mind is that the area I live in is devoid of high end anything not to mention people into hi end gear save my coworker as luck would have it! So hearing other people's gear is non existent. So the only thing I really have to go on "what is good" is my own ears and my memory of 20 years ago when I did live next to hi end shops.

I've had some growing pains on thi new system that have led me down a couple wrong paths to finally land me where I'm at now. One thing i've learned about the Thiels (as many here can attest on this forum) is that they are VERY revealing and some might even say bright. I was beginning to agree to the bright comments but a salesmen at Audio Advisor said i should try the NAD M51 DAC and return the Rega Apollo R i bought from them. He had the NAD in his system and loved it, prior to it he said he hated all digital equipment and was a vinyl guy - he is a salesman so who knows right? I thought I'd give it a go. So the NAD arrived a couple days ago and I wired it up. Immediate first impressions was - ehh - what's the big deal. Sounded almost like the Apollo. A couple hours later would change all that. Suddenly all the bass was there and the highs didn't have the edge on them anymore. The soundstage was huge and instrument placement and space was there in spades. There was however the small tinge of brightness. Just for kicks, I took out some old Staight Wire (all copper wired interconnect) and switched out my just as old but in current use Tribtaries (silver wired interconnect) and voila - smooth as butter, or at least smooth compared to the Tributaries. Didn't think wire type would "show" so much but these new speakers reveal any and all changes to the system no matter how big or small.

I'm not great with describing hi end audio impressions but what I can say is this: I'm notorious for listening to CD's for 30 seconds at a time and jumping from one song to the next hoping to stumble upon sonic nirvana but never being quite satisfied. What the NAD did for me, and the biggest compliment i can give, is that it allowed me to listen to whole albums as if it was the first time I have ever heard them and forget about the gear! I listened to Pink Floyd's "Whish You Were Here" - an album I've listened to for 20 years and know intimately - from beginning to end and hear things I've never heard before. . .Now back to the listening!

Associated gear
Thiel cs2.4 loudspeakers
Kimber Kable 8tc speaker cable
Vincent sp331 amp
Straight Wire Encore interconnects
coax interconnect (monster)
oppo 93 (as transport)
Sir, I note that you own a BDP-93. Would you suggest that the NAD delivers a far more compelling sound than does the well respected Oppo? I happen to own the BDP-95 which uses a higher grade DAC but in search of a standalone unit I could live with for many years. That's not easy in the ever changing DAC world.

Nice review, thanks for that.
I have not ever used the Oppo for anything more than a trasnport. So I cannot comment on the quality of the Oppo 93 or for that matter the 95's sound, though I have heard good things about 95's sound. However, I did own a Rega Apollo R CD player which is highly regarded and the NAD blew it away. My guess is that a stand alone DAC of the NAD's quality would be superior to the Oppo's all in one unit, but this is my pure conjecture. There are a few reviews online from independent owners that all rave about the NAD and how it competes against machines costing more. This machine is rather new so there arn't many reviews out as of yet.
I've recently purchased a NAD M51 as well, can attest that its a great DAC, I also have an Oppo BDP83SE - which is now fed through the DAC after some a/b listening. The NAD is more balanced.
Today I just hooked up my new cardas light interconnects in balanced configuration to my CIAudio d200 mkii's. Amazing!!!! In my set up balanced is truly eye opening.
I just got my M51. There are layers upon layers of music that I was missing. I've had a 32 bit ESS (EE Minimax Dac), 16 - 20 bit NOS highly regarded ( Adcom GFA-700, McCormack DAC1), 24 bit highly regarded (CA dacmagic) and 1 bit sigma delta tube output stage (Conrad Johnson DA2b). These are all fine dacS and great performers. Fortunately, the M51 is a step above. I am using with my CJ ET3 SE. I will need try it direct for a longer period. I tried briefly but went back to my CJ.
The M51 is on my radar at the moment, the feature that attracted my attention was PCM support via HDMI. However the next shipment isn't due until late July and all dealers in my country are out of stock. I am currently using my Halcro SSP for both 2 ch and 7.1. The idea of the M51 is to take over from the Halcro to make a more stand-alone 2ch setup. I have tried another hi-end DAC in my setup (PS Audio Perfect Wave DACmk2) however the Halcro beat it hands down. I'm wondering if anybody here has tried both the PWD2 and M51 and have an opinion as to which is better? The PWD2 is significantly more expensive but it does do more stuff than the M51 (eg network streaming).
Can you please confirm if you were using the built in volume control of the M51 or you had a separate PreAmp. And if you are, then did you have chance to compare it with a dedicated premap?

I currently have the Rega Dac, which I really like but I am evaluating a good Dac with the built in volume control as I only have need for one digital in from my music server. Unless I am convinced that having a dedicated PreAmp is still better then the built in volume control in a DAC.
I use the built in volume control of the M51 strait to the amp - no preamp. I found the presentation of the music much more open and less veiled when going strait to the amp from the DAC. One note though, I use XLR to the amp from the preamp. When I tried my preamp I had to use RCA connects - the music wasn't as open or neutral. I've read the M51 performs better when using XLR IC's. Also, I notice zero downgrades or downsides using the built in volume of the M51. It performs flawlessly.
I received my M51 ~25 days ago so I've been spending some time testing with the M51’s generous amount of connectivity.
I've written this review on another site some weeks ago and thought I'd share/add to AG comrades.

Comparisons with other DACs although not directly AB’d are relevant in my mind as we’ve gone back and forth and noted the strengths and weaknesses of these DAC’s in our system. Our system consists of;
Preamp is an Allnic L3000
Amp is a pair of Joule Electra VZN100 MK III’s.
and now a
Arcam 7 channel amp since I've rendered my Joules unusable :(
Speakers are GR-Research Super V’s.
DAC’s used are Eastern Electric Minimax
Tranquility SE
Oppo BDP-95

We have been enjoying both the EE dac and the Tranquility SE, both offering a very different perspective in music. The Tranquility we find a smooth performer in that it seems to tame the brightness we’ve come to know in many of the popular recordings. It is smooth yet it still retrieves a good amount of detail. In an aggressive system I can see this as a good match, or, with folks who are sensitive to harshness and or upper frequencies, or are just not used to the matter of factness of some equipment.

The Eastern Electric is a very different animal. It renders great space and a wider soundstage perhaps through the way it magnifies and highlights. I was able to AB this DAC against the Oppo, level matched and found that the Oppo narrowed the stage but gave us a very solid central image where the EE seemed to broaden everything. With the EE tube employed the image softened and wasn’t quite so dynamic.
The NAD has been quite something. Hang with me I’m not very good critiquing. Natural is my first impression. That’s the first adjective to describe the NAD. Now when I go back and play the Oppo it sounds slightly harsh and aggressive. The Tranquility sounds slightly rolled off and the EE sounds slightly mechanical. Now I’ll back up because using different connections gives very different outlooks.
Connected through a Macbook Pro running Audiovana, USB into the NAD, I didn’t care for its character. It sounded a bit clinical and lacked the warmth and beauty we experienced through Oppo HDMI. Using the Oppo as a streamer (hard drive attached via USB) I connected through HDMI which employs an I2S bus (this according to both NAD and Oppo engineers) and sent balanced out to the Allnic preamp, this has been by far the best connectivity in our system. This isn’t a “wow, did you hear that”, or any one trick pony, this is something that seems to have all the attributes of vinyl, only none of its negatives. Against my vinyl setup, VPI Scoutmaster, Dynavector XXV MK III with Soundsmith’s best tip) I think I'm preferring my digital system. The NAD seems to scrape away an amazing amount of information from the file (FLAC and WAV) and present it vividly but without an aggressiveness that is usually the sacrifice for such information retrieval. Listening to vocals this is where I thought I’d pack up my vinyl rig and bid farewell. I thought my system performed vocals well before the NAD arrived. Now I have to wonder why I even thought that. This is part of the connection, the way the vocalists sing with ease yet nothing is hidden or rolled off. The textures and fabric of the music is simply amazing. Drums beats which is already the best period on this system took on another level of authenticity. The 2 each servo controlled open baffle woofers, powered by some Rythmic plate amps offer bass with little to no overhang I’ve ever been able to detect and with great texture. With the NAD bass got slightly diminished in favor of texture.

Let me throw some examples out there.
B-Tribe “Suave Suave” there are some serious bass pedal notes. We are talking low octave stuff. The notes are there only now more delineated as I mentioned. It’s hard to describe. You cannot help but take notice of this. I played Dave Mason “Alone Together” a favorite of mine way back when. What struck me was that this song sounded like it did “way back when”. It was not changed, rather, it was portrayed in whole, Dave’s voice so unbelievably natural, it brought tears to my eyes. It was beautiful. It wasn’t a DAC playing, it was music playing. I had always thought this recording was soft and rolled off. In this instance it was dynamic yet controlled, detailed yet not at the expense of the song. You could still follow along with the pieces of the song or just take it in as the entire melody. I had to play it again. Playing Sia “Some People Have Real Problems” Beautiful Calm Driving, her voice came across so vividly yet so natural, you were simply drawn into the music. Surrounding her voice was all the texture and timber that had shown in other dacs, but not as vividly or as naturally. There just seems to be a good balance of detail and texture but without the expense of the music. The following song Lullaby, I don’t play much if at all but now I was captivated by Sia’s voice. It was so clear, so intimate, it was simply mesmerizing. The NAD was begging for bad recordings. Journey’s first album when Journey was “Journey” Neil Schon on guitar, “Of a Lifetime”. This recording took on a new life, not changed so much just more textured, greater separation and still the same excitement but not at the expense of driving you out of the room.
Next night I played some Eric Clapton, Me and Mr. Johnson. Whoa, the performance was in the room. Great dynamics, tone and timber, with great separation of instruments. Again, you became very involved in the song, toes tapping, I mean you’re swinging in the rhythm. Off to Eric’s Reptile and still, so fun to listen too. You can go from nostalgic to intimate to fun with this DAC. I spun Peter Frampton’s “Thank You Mr. Churchill” on SACD. This recording starts out very dynamic with an amazing bass line that all morning long has been playing in my head sounded awesome until the very dynamic passage kicked in. On all other setups I’ve had it was tough to listen too. Even with the NAD I had to turn it down from my stadium level. It is not going to fix bad or strangely recorded music, at least it didn't in my system, but I've found very few that I haven't enjoyed.

Most important, the wife gives it a big thumbs up.

I received my NAD M51 today and found that it had a metal screw rattling around inside and had to remove the four hex screws to lift the "U" shaped top off before daring to power it up. Apparently the assembler in China forgot to put the last screw in that holds the face plate on. I finished his job and completed the installation. Wow, what wonderful music comes through this amazing DAC/Preamp. Adjectives: Dynamic, warm, accurate, sweet, alive..... I'm using XLR between it and the power amp and even though nobody mentions it, the M51 has stereo RCA outputs that work in tandem with the XLR jacks, to feed a subwoofer. Source Oppo 95 hooked up with HDMI out to HDMI in on the M51. The lack of an onboard volume control is easily solved with a programmable remote so you can safely lock the NAD remote away for safe keeping.
The NAD M51 is sweet and worth every penny. Javon Jackson's
"Easy Does It" is like a live performance in my home.
Guys, thanks for this thread! It tipped me over the edge. I've had a PS Audio Digital Link III for years, and I love it. Still do. Found it hard to believe that the NAD M51 could be that much better. Holy s#1t! Whole new ballgame. I think it's that NAD is first to have really solved the jitter problem. Why it's turned heads with vinyl diehards. And Stereophile called the sound "tubey." But the increased level of detail and realism is just stunning. And I too find it non fatiguing. Hard to STOP listening! Breakthrough product.
The M51 outputs both on XLR and RCA. After reading Dessalvo55's post, I was thinking of doing something similar, specifically feeding my amp with XLR and using the RCA output as a line-level signal for a headphone amp, etc.. Just be aware that there is only ONE digital volume control and it is intrinsic to how the M51 does processing. If you are using the M51 in "variable" volume mode to control your XLR output, it will similarly control the RCA outputs. The RCA output will NOT be consistently line level. That prevented me from using the M51 in "pre-ampless" mode in my "standard" configuration. Unfortunately, I don't think it would be easy for NAD to solve this one; I think it would require a second, parallel signal path. It would have been nice, but I understand. Just be aware.
I recently purchased the Nad-M51 it is very good ,I have owned the Bryston
Dac and this dac is more resolved and involving.i recently owned the Ayon
Skylla-2 dac and the nadm51 with th Bryston digital player I purchased
Is actually more detailed and balanced ,the Ayon is a softer and a little more analog if you will ,not as good for driving rock and roll though.
The Oppo -95 I own is for good especially for 3d video ,sonicly
Not in he same league as the Nad. I did want to point out that the external
USB drive I use the Excellent Wireworld USB cable ,as well as the Platinum XLR digital cable. These are accurate statements.
The Bryston bdp is a great addition to improve any dac.
If you own the Nad-M51. Here are a few tweaks hat work.
To stat buy a quality power cord $3-400 is what I insider pretty good
On average,the fuse on the back is a Huge bottleneck steel fuses have 8x the resistance than the Hifi tuning Supreme fuse ,but one slightly bigger 1.125a ,29mm long ,-slow blow it us directional have the arrow pointed to the Right. Inside get some blue tak around ythe seams to absorb vibration.
Herbies makes Big tender feet I youse 3 , and 2 Vibration damping discs
Ontop spread out. If you want to buy rf caps for unused outlets and for xlr
This is an added benifit.Everything counts, allways clean all your contacts
Including speaker cables and iec blades on power cords.
Kontak makes a great cleaner. If nine use 91 percent alcohol with cotton swabs ,take most iofthe cotton off and clean untill no black oxide comes off
This is total dedication as an Audiophile I am a little extreme.
For the aftermarket fuse buy a Hifi tuning Supreme fuse 1A slow blow
20mm.slow blow
"What the NAD did for me, and the biggest compliment i can give, is that it allowed me to listen to whole albums as if it was the first time I have ever heard them and forget about the gear!"

That's the ticket! And one of the reasons NAD has been around even in audiophile circles for so long.
Couldn't agree more with all the praise. I have the NAD M2 integrated amp which uses the same DAC technology as teh M51...
The m-51 dac is more complete sounding the the M2 for it has much better isolation,and much more power regulation of the power supplies ,much more real estate to incorporate the extras.
It is like good seperate components, the dealer confirmed this as well as NAD.
I just received the M51 and it's amazing. Can't believe the amount of detail I'm hearing from CDs I've listened to hundreds of times. I've heard from someone with a sophistical listening sensibility (but can't confirm through direct experience) that the NAD "Direct Digital" amp is also a complete upgrade over 99% of amps out there.
I've been listening to my M51 since last October, and I STILL "cannot believe the amount of detail I'm hearing." I've been working my way through my library and continue to be amazed. Everything sounds new. Lots of fun sharing with friends who mutter for hours, "I never heard that before..." Enjoy!
I'm trying to follow your music flow as stated in your comment. You said you are feeding your OPPO BDP 95 via USB (is that USB coming from your Mac Book Pro?), then you take HDMI out of the Oppo and feed the Nad M51 - which in turn feeds a balanced output to your amp - correct? But earlier, you said you didn't care for the USB feed directly to the NAD - right? So, somehow the OPPO's HDMI output has cleaned up the same USB source from your Mac Book Pro - is that right? Thanks for any further clarification you can offer.