Nagra Tube DAC và Classic PSU Power Supply: Âm thanh vượt trội… xứng đáng! Đánh giá bởi Tom Lyle

 

January 2021

Nagra Tube DAC And Classic PSU Power Supply
Sonic glory… worth it!
Review By
Tom Lyle

 

 

  Nagra
is a Swiss audio equipment manufacturer that has been in business for over 65
years. Their professional portable tape recorders were an industry standard for
many decades, even appearing as props in many films and television shows. Their
reputation was rock-solid even before they started manufacturing high-end audio
equipment in the 21st Century.

Because of this, and because of the fine high-end audio
components they’ve been designing and manufacturing since 2012, I suppose there
are many audiophiles, and plenty of non-audiophile, who might add the Nagra Tube
DAC and its matching Classic PSU power supply to their systems without an
audition, or without reading reviews on the subject. They might not even discuss
this purchase with anyone else, other than perhaps their significant other.

 

Current
Less than two years ago I reviewed Nagra’s most current
linestage, the Enjoy
The Music Legendary Performance award-winning Nagra Classic Preamp. Ever
since then, it has become my reference. I didn’t need much convincing to accept
the assignment to review the Nagra Tube DAC / Classic PSU package. Nagra calls this DAC a “no compromise design”, and after
living with it for a few months I’m forced to agree with them, even if just
considering its sonic aptitude, which I’ll discuss in more detail in a bit.

The Nagra Tube DAC is essentially a two-cabinet component. It
is powered by their Classic PSU, which supplies optimal power to the converter. The Classic PSU can not only supply power to the Tube DAC but also can be used
with Nagra’s VPS phono stage, their JAZZ and Melody preamplifiers, their Classic
DAC and HD DAC converters. Because the Classic PSU has three outputs, I was also
able to enjoy the instantly recognizable increase in sound quality when I used
it to power the Classic Preamp that currently lays down the law in my main
system.

 

 

Since this preamp has an IEC input on its rear panel, one can also use
its internal power supply by connecting a power cord of one’s choosing, and then
plug that into an AC wall receptacle, or an outlet from any source of 110V AC,
such as a power conditioner. The Nagra Tube DAC does not have an internal power
supply, and instead, it relies on the Classic PSU to supply its juice.

In keeping with Nagra’s no-compromise design or perhaps for
reasons not completely understood by mere mortals like myself, the Tube DAC
requires two power lines from the Classic PSU, one to power the digital circuit
of the Tube DAC, the other to power its analog circuits, including its 12U7
vacuum tube (called an ECC82 tube in Europe). No compromise, indeed.

 

Inspired
Inspired by the design of Nagra’s HD DAC, the Tube DAC uses a
new digital core built “on the experience gained” from that component. And so,
the Tube DAC features an entirely new converter and a new USB interface. The
result, says Nagra, is a “major improvement” in the sound of every digital
format it converts, including Red Book CD via its S/PDIF coax input. I’m not
sure it’s worth mentioning that The Nagra Tube DAC can reproduce DSD 256 and 384kHz PCM signals, since all modern digital-to-analog converters worth considering
these days can do so.

 

 

Nagra insists that it’s no-compromise design is not only in
regards to its digital circuit, but its analog section as well. The normal use
of steep slope filters has been done away with, and because of this, Nagra says
that one can hear the transients and harmonics that were on the original
recording, which translates into the music having a more life-like quality. On
their website, Nagra continues touting its Tube DAC, by saying that it uses some
very impressive internal parts, including “ultra-high” performance drivers, and
hand-wound transformers. 

 

Auditioned
The Nagra Tube DAC / Classic PSU package was auditioned in my
main system that is set up in my acoustically treated dedicated listening room.
I might be overstating it a bit when I call it a “dedicated” listening room
because there are other things in the room beside my system and my cheap but
comfortable IKEA listening seat, but everything in the room is in the service of
the audio system, which includes a desk and computer.

Also in the room is my large vinyl collection, which many
consider acoustic room treatment, and the computer on the desk is a music server
which is loaded with Foobar 2000 and J River Media software that sends a signal
that comes through a USB port, which uses a Wireworld Platinum Starlight USB
cable to send its signals to the Nagra Tube DAC’s USB input. Also connected to
the Nagra’s rear panel, using an Accusound “Digital Link” 75-Ohm coax cable was
an OPPO UDP-203 Blu-Ray/universal disc player, this way I could listen to the
occasional SACD or audio DVD.

The Nagra Tube DAC was supported by the Nagra VFS (Vibration
Free System) which consists of two base plates, placed one atop the other, meant
to eliminate mechanical vibration in the component that is placed on it.  Nagra says that it was originally designed for sensitive components such as
preamplifiers. There is also one under the Nagra Classic Preamp that was used in
my system for this review. The fact that both the Classic Preamp and the Tube
DAC both have vacuum tubes in their innards makes even more sense that one uses
some sort of vibration control. I felt good using the Nagra VFS under the Nagra
Tube DAC because it was manufactured by the same company as what it was
protecting, plus the Nagra VFS made the industrial-chic looking Tube DAC look
even more stylish! Between the hung shelves on my Arcici Suspense equipment rack
and the Nagra VFS, I felt secure in the fact that vibrations were kept under
control.

 

 

The Nagra Tube DAC’s analog outputs were connected to an input
on the Nagra Classic Preamp or a Gryphon Essence preamplifier, and its signal
was fed to either a 250 Watt per channel Pass Laboratories X250.8 or a Gryphon
Essence power amplifier that put out “only” 50 Watts per channel, although it uses a Class A
circuit (both the Gryphon preamp and power amp have reviews forthcoming). The
power amp de jour fed a pair of Sound Lab Majestic 545
full-range electrostatic loudspeakers. Although the “full range”
within their moniker is
technically truthful, my varied taste (or lack thereof) in music means that the
speaker’s low-frequency extension to no lower than 32 Hz demands that I augment
the speakers with a pair of subwoofers. And so, the more than sufficient SVSound
SB16-Ultra did the trick, with their 16″ drivers and 1500-Watt internal amps
filling in the lowest frequencies down to 16 Hz (+/-3dB).

Other than what was mentioned above, at the beginning of the
audition period, I started with Kimber Kable Carbon 8 interconnects, Carbon XL
speaker cable, and Ascent power cables. About halfway through the audition
period, I was sent for review Black Cat Graceline L2 interconnect and speaker
cable. This didn’t change the sound all that much, which spoke well for the
Black Cat cable, but I was able to notice these differences and take that into
account when judging the sound of the Nagra component.

I also used battery power supplies for some of the equipment,
as the power set to our home from the electric company suffers from various
sonic pollutants, especially during the day. During daylight hours I connected
the power amplifier to the Goal Zero Yeti 1000 lithium battery power supply, at
night the amps were plugged directly into the wall receptacle, which was one of
two dedicated lines that run directly to our home’s circuit box in the basement.

Some of the front-end equipment was often connected to a
Rockpals 250-Watt portable lithium battery power supply (I now use this very
reasonably priced unit instead of my older Goal Zero Yeti 400.
Unlike the Goal
Zero, it has no fan, so it is much quieter). Incidentally, when the Nagra
equipment was connected to the Classic PSU power supply, I heard no sonic
benefits at all from using the battery power supply, during the day or night
time.

 

Diet
As many may know from my previous reviews, my digital music
diet consists largely of files stored on several hard-drives hardwired via USB
to the music server’s computer. On these hard-drives are many terabytes of
music, the large majority of these files are of “CD quality”, in other words,
16-bit/44.1kHz. I also have lots of higher resolution files, and loads of DSD
files – there are somewhere between three and four terabytes of DSD files
residing on these drives. But I’ve been collecting CDs since the 1980s that have
now been ripped, along with others downloaded from the internet via broadband.
In just the “Rock” folder there are 17 terabytes of music stored on the drives.

This means that any DAC I use better sound pretty darn good
when converting these lower resolution files. I don’t mean that CDs should sound
as good as DSD files, but that the converter should earn my praise just as much
when playing either. Spoiler alert: The Swiss-made Nagra Tube DAC/Classic PSU
combination renders the best digital sound I’ve ever heard in my system, from
any DAC I’ve ever used, regardless of the file’s resolution.

 

 

No, I’ve never auditioned a ~$108,000 complete DSC Vivaldi
digital playback system or its equivalent in my listening room. So, as I praise
the Nagra as the best I’ve heard so far, I should mention that for the last two
years I’ve been using a $25,000 EMM DA2 digital-to-analog
converter. Even though
it doesn’t cost as much as a BMW M5, or a full DSC Vivaldi digital playback
system, it reaches very far into the “excellent” category, where it is rather
difficult to find fault with its sound. I’ve had many other DACs throughout the
years, their sound quality incrementally improving. And even though I bet with
many systems the difference between the EMM Labs and the Nagra might be measured
in nuance. But still, the most significant improvement has been with the Nagra.

The Nagra Tube DAC / Classic PSU combo goes farther in making
improvements in digital sound quality in my system, making instruments and
voices sound very realistic, having a dynamic distance between sounds, and also
entering the same category as the award-winning McIntosh MC611 solid-state
monoblock amplifiers that both Enjoy the Music.com‘s creative director Steven
R. Rochlin and I reviewed in the summer of 2018. In my review, I called these
McIntosh amps “beautiful” sounding. As with the McIntosh, the Nagra Tube DAC
system sounds more pleasing to the ear than any other DAC I’ve ever heard,
anywhere near its price.

This “beauty” is not a coloration. When playing any files of
well-recorded music, the Tube DAC does this with what sounds as close to
absolute transparency as we’re likely to get anywhere within its price range.
No, this price range isn’t low. But it translates into the overall sound quality
having the gestalt of “real” sounding voices and music.

When I say that this DAC system sounds beautiful, I mean that
it has the beauty of real music. When listening to a live instrument or voice it
sounds pleasing to the ear. At least it should. Well-recorded music should also
sound pleasing to the ear. Like real music (as long as it’s not played too
loud!). And this type of “reality” is what I assume is the goal of
high-end audio! The Nagra Tube DAC/Classic PSU package comes closest to sounding
like this than any other DAC I’ve ever had in my system, or heard in many other
systems and within audio salons unless one considers digital systems costing
much, much more.

 

Playing
I had a blast playing the DSD of Boulez Conducts Ravel
a compilation on Sony Classical of recordings made in the 1970s with the New
York Philharmonic and the Cleveland Orchestra. Believe it or not, there might be
readers who are not familiar or only slightly familiar with these popular Ravel
pieces that some classical music lovers might derogatorily call “warhorses”,
in other words, played so many times that they become overly familiar. We can
remind those who say this that they have been played so often because they are
very, very good works of music.

 

 

If one is unfamiliar, or only slightly familiar with Maurice
Ravel’s catalog this SACD is highly recommended. Another reason to recommend
this SACD is that its sound quality is second to none. And the Nagra Tube DAC
took full advantage of this. An amazing display of both microdynamics and
macro-dynamics, yes, but also dynamic distance, where instruments that were
located very close to each other in the Tube DAC’s huge soundstage, but also
seemed to be playing at the same volume, were separated by an appropriate
distance within the front soundstage. This was very apparent in, for example, the climax
of the familiar “Bolero”, which is the first piece. I must have heard this piece
played in concert and on my system a thousand times, and played through the
Nagra Tube DAC I could hear details I wasn’t familiar with coming from the rear
of the orchestra; these instruments’ location in the soundstage was located way
beyond my rear wall.

On “La Valse”, I could hear these traits even better than on “Bolero”,
as this piece is more of what I like about Ravel’s impressionistic
orchestration, the nebulous groupings of winds and strings, mixed with the
occasional harp glissando, sonically painting with pastels outside the lines.
The Nagra Tube DAC was the antithesis of what I negatively term “digital”, as
the midrange and lower treble made me appreciate Ravel’s attention to form and
craftsmanship while disregarding the buttoned-up approach of the romantic
composers a bit father East. His sonic brushstrokes using the winds and strings
sounded voluptuous, as he surely intended.

 

 

As I emphasized earlier, regular CDs sounded amazing through
the Nagra Tube DAC. How amazing? There were more than a few times during the
review period while playing a file through the Tube DAC / PSU combination I
instinctively got out of my listening seat to flip the LP over to side two, but
then realizing that I was playing a file through the USB port of my music server
connected to the Nagra Tube DAC’s USB input. I don’t remember which album it was
when that happened, but it could easily have been when I was playing Atomic
Rooster’s album Death Walks Behind You.

The British band’s second and most successful album was released
in 1970. Many fellow hard-rock aficionados remember this band, but they are not
a household name, even those living in the UK. But they had two tracks that
charted, one of them, “Tomorrow Night”, is from this album, on the charts for 12
weeks, reaching as high as number 11. Even though I suggested that they are a
relatively obscure band, they are remembered by some progressive rock fans
because in their ever-changing lineup drummer Carl Palmer, later of the band
Emerson, Lake & Palmer, played on their 1st album.

When playing this album, I had no intention of using it as a
musical example in this review. But when the first track began, bandleader and
keyboardist Vince Crane starts off the track with piano, and I nearly fell off
my listening seat it was so realistic sounding. The band enters, it doesn’t have
a very memorable melody, but it has a certain groove that I bet was “danceable”
in its day. The way the Nagra Tube DAC was able to dig into the sound of the
tune, and also take advantage of its vintage multi-track sound, as I was
normally accustomed to spinning my German LP pressing on Philips, half expecting
to hear the occasional crackle from my ancient copy.

I realize that this description is a bit obtuse, but it was
quite remarkable how little “digital” sound came through this plain vanilla
16-bit recording. Rather than slightly boost the upper midrange, it sounded more
like the LP, a bit scooped out in that region, letting me listen to the entire
album with zero listening fatigue.

 

 

I listened to the Mobile Fidelity Sound Labs DSD files from
the Art Pepper compilation album …The Way It Was! On the
Hammerstein and Kern standard “All the Things You Are”, recorded in early-stereo
from 1956, at one point in the song, Art Pepper on alto sax and Wayne Marsh on
tenor sax are soloing simultaneously in the left speaker. Even while soloing in
tandem, they remain sonically separated, even though both instruments occupied
only a small area in the faux soundstage. Gary Frommer’s drums and Ronnie Ball’s
piano both share the right speaker. Many listeners, including myself, sometimes
find this hard panning to one speaker on jazz recording objectionable, so it
makes sense that many jazz fans opt for the mono version of some albums when
available. But even on this dual-mono recording, the Nagra Tube DAC rendered
each instrument with such a captivating, lifelike sound that it drew me into
this outstanding music.

This reminded me of hearing live jazz, where when my attention
would shift from one instrument to the other and it would become a sort of
meditation. I was listening intently to Ball’s piano vamp on the right and
slightly behind the band, then my attention turned to Frommer’s drums, which
were a bit low in the mix, but the recording, and thus its reproduction was
still good enough to hear them very well, especially the ping of his ride cymbal
and swish of the high-hat, as my toe-tapping and head-bobbing continued
throughout the number. I love it when that happens!

 

 

Sound
In my system, the sound of the Nagra Tube DAC/Classic PSU was
seductive. Each recording that was converted into a musical signal would draw me
into the music. Each note I heard was the best I’ve ever heard — until I heard
the next note that came through my speakers.

This Nagra converter was dangerous, as I’d be listening to
music long past the time I should have stopped, often keeping me up late at
night listening to music long past the time I should have retired. I was also
late for a few meetings on Zoom. “It wasn’t my fault, I’d say”, it was Pete
Townshend’s, as the recording of his appearance with his band The Who at Hull
City Hall, February 1970 made it impossible to stop listening until the two-CD
set’s last track, a nine-minute version of ‘We’re Not Gonna Take It’ was over”.

Or perhaps I should blame the designers and engineers at Nagra
for making such a fine piece of equipment, because it acts as a siren, tempting
me to listen to one more song, one more album, one more artist, one more
recording. Don’t say I didn’t warn you. The Nagra Tube DAC with its
Classic PSU power supply will make the sound of your digital files connected to
its USB port, or discs player connected to its coax input sound better than you’ve
ever heard them before.

 

 

I think that priced at $27,000, the Nagra Tube DAC is worth
every penny. And I would also think that it is very competitively priced. That
is if one already has a Nagra MPS or VFS power supply. This is because if one
doesn’t already have a Nagra power supply the Tube DAC / Classic PSU package,
which also includes the VFS base is $46,000, and I’m not willing to call that
price anything other than what it is. But, wow, is this a magnificent sounding
digital-to-analog converter!

I also consider it a safe bet that any audiophile that has a
system that can appreciate its sonic glory and has a pair of ears will agree
with me that the Nagra Tube DAC mated with the Nagra Classic PSU is a very
high-performance audio component. It is also one that demands that I politely
request that if one purchases the $46,000 Nagra DAC package, or even the $27,000
Tube DAC sans Classic PSU, they donate to a deserving charity. If one cannot
find a worthy charity, I will be glad to suggest one. I very highly recommend
the Nagra Tube DAC/Classic PSU package (or the Nagra Tube DAC if one already
owns a Nagra power supply) to all audiophiles who can afford it. Absolutely!