May 2024

Nagra Classic DAC II, PSU Power Supply, And VFS Review
Bringing tears of joy when listening to special songs.
Review By Tom Lyle

  In January 2021, I was fortunate to review Nagra's Tube DAC and Classic PSU power supply. In my review, I said that the owners of this vacuum tube Hi-Res Audio DAC will be able to appreciate the "sonic glory" of this "high-performance component." So, I was not surprised that the Nagra Tube DAC and its PSU power supply were awarded Enjoy The Music.com's Best Of 2021 Award.

After I finished the review, I was not psyched to return the $40,900 package consisting of the Nagra Tube DAC, Classic PSU power supply, and VFS Classic base to the distributor. I was captivated by the sound quality this digital front end contributed to my system. My reference DAC, an EMM Labs DA2, is no slouch, but this Nagra Tube DAC package costs twice as much. It was not twice as good as the EMM Labs converter; it doesn't work that way, but the improvement in sound quality was significant. I jumped at the chance when I was offered the subject of this review, the relatively new Nagra Classic DAC II / PSU / VFS combo ($18,500, $16,900, and $2750 respectively).

Nagra
The Nagra Classic DAC II joins the rest of Nagra's Classic line, which includes their Classic Amp and Preamp, the Classic Phono, and the Classic Int (integrated amplifier). There is much to like about Nagra components. I love how they are designed to mimic the look of Nagra's vintage reel-to-reel tape records. Nagra gear looks fantastic, and even better is the Nagra component's exceptional sound quality.

The Classic DAC II digital-to-analog reviewed here doesn't have a zillion features. It was designed and built for only one function – to convert a digital signal to an analog signal. It does not have a volume control, and its users do not have to scroll through various digital filters to find one that suits them. This straightforwardness was reflected in the ease of setup of the Nagra Classic DAC II.

PSU
Like the Nagra Tube DAC, I was sent a Classic PSU power supply and VFS bases for both the converter and the power supply. Still, all that it took to set up this digital converter and its power supply was to place the Classic DAC II and PSU on their respective bases, connect the "haute horlogenic" DC power cable from the rear panel of the PSU to the rear panel of the Classic DAC II, connect the power cable to the PSU's IEC input, and then power everything up. I was then ready to listen to music.

Listening to the Nagra Classic DAC II without the Classic PSU power supply is possible, as it has its own IEC AC power cord input. Since its internal power supply has been upgraded from early models, many will be perfectly happy with the Classic DAC II's sound without the accompanying Classic PSU. However, the improvement in its sound quality when using its outboard power supply was very noticeable, so I used it this way almost all of the time, other than the brief period when I tested it to hear how it sounded without it.

Coltrane
During the audition period, I played a Coltrane album, credited to the John Coltrane Quartet, The John Coltrane Plays, a DSD file ripped from a hybrid SACD on the Acoustic Sounds label. It only took a few minutes into the first track to realize that this digital copy of this album never sounded this good on my system. The music coming from this Nagra DAC made me feel like I was a fly on the wall of Rudy Van Gelder's studio in Englewood Cliffs, New Jersey in 1965, sitting on the control room couch listening to the playback of the session.

Yes, this version of John Coltrane Plays was the stereo version, with Cotrane's sax coming out of the right speaker and Elvin Jones's out of the left speaker. But the piano and bass took up most of the center-fill. Even though many, including myself, have become accustomed to Rudy Van Gelder's rather unconventional style of mixing a stereo recording. It did not "ruin" the album's sound. I basked in the sound quality of the Nagra DAC, and, as usual, I was amazed at the stream of consciousness contained in the solos of John Coltrane. The level of talent contained in this John Coltrane album was a revelation.

I never considered John Coltrane Plays an audiophile showcase. Despite the unorthodox mix on this album, I heard a highly detailed sound that never sounded etched. The treble on this album seemed extended as high as the master tape could reach, yet there was zero sibilance. The midrange was as transparent as I could wish for.

But here it was, one of my favorite late Coltrane albums, practically bringing tears to my eyes when listening to it through this Nagra DAC combo. What sort of magic was contained in the chassis of these components to make a sound that was so honest? 

NADM
The Nagra Classic DAC II uses the same NADM (Nagra Audio Digital Module) digital engine in their pricier HD DAC X and Tube DAC. The Nagra Classic DAC II can decode all current high-resolution formats, including very high-resolution formats such as DSD 4x (256) and DXD.

Red Book
Thankfully, Nagra spent a good amount of research and development on the conversion of red-book (also called by many as "CD quality," or 16-bit/44.1 Hz) signals. I was thankful because the majority of the files that I store on my hard drives are ripped from my extensive CD collection or from files that were downloaded with this resolution. Nagra claims these files will "reveal striking resolution and musicality for the still vibrant format." Thank you, Nagra!

The Nagra Classic DAC II's output stage has a discrete topology and operates in Class A. According to Nagra, this converter features "superior quality" components and uses military-grade transistors that are "individually measured and selected."

The Classic PSU power supply can power three Nagra components. As I mentioned previously, to send power to the Classic DAC II, all one must do is connect the supplied DC power cable from the PSU's rear panel to the input on the DAC's rear panel. Done.

On the Classic DAC II's rear panel are a pair of outputs, in this case, two RCA jacks (the Nagra Classic DAC II has no balanced XLR outputs). Its "input block" has digital inputs for USB, optical, AES, S/PDIF, and inputs for use with a complete Nagra system: its Optical Nagra Link.

Power
Since the Classic PSU has three DC outputs, I could connect one of its DC power cables to the Nagra linestage. It did not matter how many components were connected to its DC outputs. I heard no loss in sound quality on either of these components, whether the PSU was powering one or two components. In fact, the opposite was true. There was a small but very significant improvement in sound quality to any component I connected to the Classic PSU power supply.

System
My reference system hasn't changed much since my last review. I've previously mentioned that the Nagra Classic DAC II's outputs were connected to a Nagra Classic Preamp linestage. I sometimes switched out the Nagra linestage, replacing it with a two-chassis Pass Laboratories XP-22 linestage. Regardless of which linestage I used, its XLR outputs were connected to a Pass Labs X250.8 power amplifier, and its speaker outputs were connected to a pair of Sound Lab Majestic 545 electrostatic loudspeakers.

My Sound Lab speakers are touted as "Full Range," as their low frequencies reach 32 Hz, which is not bad for an electrostatic speaker. Since I listen to various music genres (there are only two: good and bad. I listen to the good), I have two SVS SB-16 Ultra subwoofers, each with a 16" driver, one placed behind each speaker. This lowers the bass response to a satisfying 16 Hz.

The digital source I used for most of this review was a computer-based music server that used Foobar 2000 or JRiver Media music software to play music stored on hard drives connected to the computer. I also used Tidal and Qobuz streaming apps loaded onto the computer. The computer's USB was connected to the Nagra Classic DAC II's USB input using a Wireworld Platinum Starlight 8 USB cable.

When I occasionally spun SACDs or DVD audio discs, I used an excellent-sounding but discontinued OPPO BDP-203 Blu-ray / universal disc player. Its analog outputs were connected to the lineage, and its digital output was connected to the Classic DAC II's coax input.

Accusound's Digital Link 75-Ohm digital cable connected the Oppo disc player to the Nagra DAC, allowing me to play the occasional CD. The system's interconnects were predominantly Kimber Carbon 8, and the speaker cables were Kimber's Carbon 18 XL.

Daylight
During daylight hours, the reference system's sound quality does not reach its full potential when connected to the AC wall outlets. I've used all sorts of power conditioners, but the system sounds much better when I use battery power supplies for the front-end equipment and the power amplifier.

So, during the day, I connect the power amplifier's AC cable to a Goal Zero battery power supply, and Rockpal's lower-wattage units power the front-end gear. These power supplies are not made for audio; along with other inconveniences, they have cooling fans running almost continuously. I'm lucky because I can store the battery power supplies in a closet behind my Arcici Suspense equipment rack, which makes the fans inaudible. After about 6:00 PM, the AC power supplied by my local utility provider is more than good enough. I use the AC power from the two dedicated AC lines, which are directly connected to the circuit box in our basement.

Genre
The Nagra Classic DAC II / Classic PSU power supply combination, supported by VFS bases, could not care less about what genre of music I played through them. Those who know me know that I listen to many different music genres, and it seemed like I played most of them during Nagra's audition period. Of course, high-resolution selections sounded better than plain old Red Book CDs.

I've used some very good DACs in my system, including my reference EMM Labs DA2. But I cannot remember a time in recent memory when these plain vanilla CD files sounded this good. I'm sorry for this spoiler alert: I can't remember the last time I spent so much time listening to 16-bit/44.1 music files.

Gear
One might ask, "How did the Nagra digital gear sound?" That's tough to say since I didn't "hear" this digital converter; I only heard the music that sounded better than ever. What more could one ask for in a digital converter? For those who remember the roll-out of the first CD players, a statement like this might seem like blatant hyperbole. Of course, the Nagra Classic DAC II could not "repair" a poor recording, but it let me hear exactly what was on it. There are very few artists who purposely make a poor recording. I loved hearing precisely what was on the recording and listening to what they came up with. Sorry, I digress.

If I were told that this DAC II was powered by tubes, I'd believe it. This wasn't because of hearing any of the negatives that some attribute to "tube sound" but its benefits, such as rendering the recording with a level of dynamic distance that is present in some of the best tube components. This "dynamic distance" enables an audio component to separate instruments, voices, and sounds that occupy a soundstage playing simultaneously. Without this dynamic distance, these sounds would overlap with each other. But this DAC could separate each sound and make them much more audible.

During the audition period, I played many recordings that weren't "audiophile quality," and the Nagra Classic DAC II let me not only hear what was precisely on the recording but also made it sound more "musical" than I've ever heard a digital copy of the recording sound. I played the album by the heavy metal band High on Fire, which won a Grammy in 2019 for Best Metal Performance for the title track of their album Electric Messiah.

This album could be considered the epitome of a complex recording, with guitarist and vocalist Matt Pike's heavily affected double and triple-tracked guitar, the bass guitar was this bombastic music's foundation, and it sounded like Muppet character Animal was seated at the drum kit, playing his complex, perfectly syncopated beats.

The Nagra Classic DAC II sorted out all the instruments and vocals on this album, so it was much easier to tell why this album was honored with this award. Despite a healthy amount of compression applied to each voice and instrument and the entire recording, their knotty compositions came to life in my listening room, surrounding me with its vast soundstage. The bass on this album reached as low as my system would allow, shaking my body, listening room, and ear-brain. Cymbal crashes were separated from the other voices and instruments, appearing at the top of the soundstage nearest my room's ceiling. I could imagine drawing a line around Matt Pike's vocals that appeared in space between the two speakers.

Conclusion
I will not pretend that the Nagra Classic DAC II is an "affordable" audio component: The list price of the Nagra Classic DAC II, Classic PSU Power supply, and VFS (Vibration-Free Support) combination is $40,900. Some might decide to forgo the PSU power supply, which lowers the price by a bit, and the two VFS bases will drop it a bit less. That means one could add the Nagra Classic DAC II to their system for $18,500.

This is still a good deal of money. But is it worth it? You bet! This Nagra digital combo is one of the best digital front ends that I have ever used in my system. It boggles the mind to think that this isn’t the best (or most expensive) in Nagra’s line of digital components. I feel that the Nagra Classic DAC II / Classic PSU / VSF package is worth every penny. But if one does purchase it, a donation to help those in need would also be nice.

The Nagra Classic DAC II, Classic PSU Power supply, and VFS bases made digital audio in my reference system sound excellent — better than it ever has in recent memory. This Nagra Classic digital front-end is highly recommended for those who can afford it!

Specifications
Type: High resolution digital to analog converter
Frequency Response: 5 Hz to 40 kHz (+0/-1dB) 
Digital Inputs: USB, AES/EBU, two S/PDIF, two NAGRA-LINK, and Optical.
Audio Outputs: Unbalanced RCA
Output Impedance: ZOUT < 430 Ohms
Output Level: 1.5 Vrms
Analog Output Noise Level: 128 dB @ 1 kHz 1.3 V (Linear)
Distortion:< 0.02% @ -20 dB
THD+N: < 0.03% 192 kHz
Crosstalk: >100 dB

Power Supply —
12V/0.8 A With MPS, Classic PSU 
12.6V/0.8 A With Classic PSU
100-240V ~+/- 10%  50-60 Hz Mains 

Dimensions: 15" x 11" x 3" (LxWxH)
Weight: 11 lbs.
Price: As reviewed $40,900
Priced As Separates:
   $18,500 Classic DAC II
   $16,900 Classic PSU (3x out)
   $2750 each VFS

Note: The PSU can upgrade the sound of up to three Nagra Classic system components (i.e. Phono, Line Stage, and DAC).

Company Information
Nagra Audio Technology Switzerland, SA
Chemin de l'Orio 30A
1032 Romanel-sur-Lausanne
Switzerland

Voice / Fax: +41 21 643 7240
Website: NagraAudio.com

Sales & Marketing Manager USA And Canada
Rene LaFlamme
Voice: (514) 826-4825
E-mail: rene.laflamme@nagraaudio.com