Review: NAD m51 DA converter

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.

FWIW.

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.