June 2018

North America Premiere Review!
Nagra Classic Preamp Review
For those who have a system that can appreciate its ultra-luculent and musical sound.
Review By Tom Lyle

  Nagra is a Swiss company that has a well-established reputation as a leading manufacturer of professional recording equipment. They were founded about 60 years ago, but it wasn't until 1997 that they also started making high-end audio equipment for home use. I was already afflicted with the audiophile bug back when Nagra introduced their first components for the high-end market, and it was then that I knew that I wanted to own one, or, at the very least hear one. I finally have a Nagra component in my system, their very attractive looking Class A vacuum-tube powered Classic Preamp.

Of course, this isn't Nagra's first preamp. In fact, they say that used their previous preamplifier model, the JAZZ, along with Nagra's HD DAC as a reference to ensure that the newer preamp outperformed the older models. And so here it is, the latest preamplifier from Nagra. It sure has the classic Nagra look, that's for sure, and that's a good thing. Although, back when I first noticed that Nagra had started designing and selling high-end audio components for consumer rather than only for studios, location recording, and other commercial uses, this "Nagra look" was thankfully still present, but personally, I thought that Nagra wasn't totally committed to their components being used it the home. This was because instead of the inputs, outputs, the power cord receptacle and the like located on the rear panel, they were situated on a side panel.

I'm sure Nagra had their reasons for doing this. But this design decision left the users of their components no choice but have cables exposed for all to see. I wouldn't have minded much because when it comes to those kinds of thing, my wife doesn't mind very much. This was true even back when our living room doubled as our listening room, although, I'm sure she's somewhat relieved that I now have a dedicated listening room, so at least that's where most of the audio gear is now located. But I've observed that in most cases I'm the exception rather than the rule, and so it must have bothered at least a few audiophiles that the design of Nagra components didn't mirror the norm.

But that was then, this is now, and so the cable connections are on the rear of not only the Classic Preamp, but Nagra's entire line. But best of all, the Classic Preamp still looks like a Nagra component. With its "Modulometer" on its front panel which shows the preamp's output level, along with its silver-colored, boxy, somewhat industrial look, in some ways it resembles the exterior of their reel to reel tape recorders of yore. It's a classic design yet looks very modern.

Outward
Even better than the outward appearance of the Nagra Classic Preamp is its sound quality. I've had some very nice preamplifiers take up residence in my system during the last few years, and in addition, during that time I've upgraded my speakers to the marvelous Sound Lab Majestic 545 full-range electrostatics. It is very easy to hear the contribution (or lack thereof) that the preamplifier or linestage, or for that matter, any component makes to this rather revealing system. I consider the preamplifier or linestage a very, very important position in the audio chain. Not only have I had the Merrill Audio Christina Signature linestage on loan for almost a year now, which can compete with some of the best made today, I also have the extremely transparent, full-function Mark Levinson No. 523 preamplifier as one of my references.

One more thing, though. Before receiving the Nagra Classic Preamp I didn't have much time to read about it. All I did was get excited that I was having the opportunity to review a Nagra component. And that it was a Nagra preamp! When I turned its power from standby to the on position via the remote, the front panel screen announced "Heating". This lasted more than two minutes before the Classic Preamp became operable. Why? This rather long warm-up is because the Nagra Classic Preamp is powered by vacuum tubes. Inside this preamplifier are three tubes "selected by Nagra", a pair of 12AX7s and a single 12AT7. Even now, very near the end of the review period, when listening to the Classic Preamp I do not hear a "tube sound". None whatsoever. What I hear from this component are characteristics of an excellent preamplifier. Period!

Internal
Of course, the first-rate sound quality of the Nagra Classic Preamp is due many factors. On the Nagra website is an explanation of the Classic Preamp's technical features, some of which I understand more than others. But one of the Classic Preamp's key internal features includes custom-made polypropylene capacitors used for decoupling and are separated from the other internal components to aid in delivering its improved performance, which Nagra characterizes as having a wider frequency response and a more linear phase response. They also use in-house, hand-wound transformers, and "ultra"-low noise right and left channel power supplies, which they claim result in a larger and more realistic soundstage. On the Classic Preamp's rear panel are five inputs, including four unbalanced RCA inputs and one balanced XLR input. Its two outputs, one pair RCA and one pair XLR allows the Classic Preamp to have some flexibility in its output scheme. Nagra also doesn't forget that this preamp might be used in a home theater setup, so they include a "true" bypass XLR on the rear panel.

On the front panel of the Classic Preamp is an LCD screen with blue-colored text, which is quite similar to the one that is featured on their Classic DAC, which besides displaying other information, will show each input's name, which can be customized by the user. Along with very smooth operating volume control and power function option controls, one can navigate the menu by its front control knob or use the provided remote to control every function on the Classic Preamp. By using the control on its front panel or the remote one can change the preamplifier's balance, input names, switch between stereo or mono, the display's native language, and check the preamp's firmware number. Although most of the time I used its remote to change its volume and mute the preamp, it was a pleasure to operate the Classic Preamp from its front panel controls. The feel of the volume and source selector are as good as it gets, and it was even a pleasure to operate the two front-panel toggle switches, one of which dims and brightens the display, the other switch to change the gain of the preamp from normal or to plus 12 dB. My description of the front panel controls of the Classic Preamp must make me sound like quite an equipment geek. But in truth, the controls of the Classic Preamp are the stereotypical embodiment of a Swiss-made, high-end preamplifier. Nagra doesn't mention much about the Classic Preamp's front panel headphone jack other than that its "high-quality" headphone amp circuit is the same that they use in their HD DAC. Since I've never investigated this other component I'll just assume that this is a good thing, as it is designed and manufactured by Nagra.

Test
I used both analog and digital sources to test the Classic Preamp. I started the review using my reference Tri-Planar tonearm mounted on a Basis Audio V turntable, but before the end of the audition period I was using the exceptional Analogue Artisan A-1 Series with a tonearm that has remote controlled VTA/SRA (review forthcoming). The phono cartridges were either the extremely transparent and involving Gold Note Tuscany or the recently reviewed and extremely capable Etsuro Urushi Cobalt Blue, connected to a Pass Labs XP-15 phono preamp using either Accusound or custom-made silver phono cables, and the phono preamp was connected to the Nagra preamplifier using MIT cable.  The main digital source was an EMM Labs DA2 processor (review forthcoming) that was connected to my computer-based music server via a Furutech USB cable, the DAC connected to the Classic Preamp using Audio Art's top-of-the-line interconnect.

The Nagra was connected to a pair of McIntosh's new MC611 power amps, and the Sound Lab speakers were augmented by a pair of 15", 1250-Watt Velodyne HGS-15b subwoofers. All the equipment except for the monoblocks sat on an Arcici Suspense equipment rack, all located in an acoustically treated, dedicated listening room with two power receptacles that are connected directly to our homes circuit boxes in the basement. The walls of the listening room are painted Sherwin Williams "Sky Fall" blue indoor acrylic-latex paint. The website RealSimple says blue walls in a home can create "an oasis of calm in a hectic world".

Music
When I started listening to the Nagra Classic Preamp play music it was immediately apparent that this preamplifier was a step-up in sound quality from my references. Even before was fully broken in I could hear the subjective improvement in sound quality it made to my system. If one thinks that price correlates to quality than yes, it makes sense that the Nagra sounded a bit better to me than my references. But I think it is also important to remember that the Nagra equipment is built in Switzerland, which means that someone has to pay Swiss people to design and build it, and so it is more than common that this price be passed onto the consumer. Still, all things being equal (even though they are not) the Classic Preamp made everything that I played through it seem as if it was the most important music that I had in my music libraries.

One of the first things I notice about the sound of a new component in my system is its bass response. Compared to my references it was obvious that the Classic Preamp's low end was not only able to reach further down into the bass region, but had a "tighter" bass sound, one that was more what I'll call for now pitch perfect. As a bass tone gets lower in frequency its pitch naturally become a bit more difficult to discern. Of course, the ability to determine a bass note's pitch in one's system is due to many other factors besides the preamp, most notably one's speakers. If the speakers don't receive a decent signal, all bets are off. The Sound Lab speakers I use are cited as being able to reproduce a signal down to 32 Hertz, which is very respectable, especially for an electrostatic loudspeaker, but certainly not as low as I'd wish. I've seamlessly matched them with a pair of 15" subwoofers, which are able to reproduce a signal down to a subsonic 18 Hz.

Does my speaker system receive signals that are lower in frequency than my reference preamps? The only testing I've done just happens to be the most accurate test equipment I've ever used for this purpose: My ears. And since I listen to tons of music where the bass is as important as any other frequency, the Nagra Preamp had much showing off to do in that area. Readers may have become accustomed to me using Kraftwerk's 1999 album The Mix to demonstrate a component or a system's ability to reproduce bass, but I listen to tons of other titles of electronic music, often on a daily basis. And so, I'd often throw on the double LP of Genesis' The Lamb Lies Down On Broadway (1975). This is not an electronic music album, you say? Well, no, it's not. Yet on much of it bassist/guitarist Mike Rutherford uses a Mister Bassman bass pedal synthesizer made by the small British company Dewtron on all of Genesis' albums from Nursery Chryme (1971) onwards, up until 1976, which is when he replaced them with Moog Taurus I bass pedals. On "Fly On A Windshield", the second track of "The Lamb…", Rutherford starts playing the pedals after the first verse of the song and continues to growl and thunder underneath it for the remainder, using only one note at a time since these were monophonic (as opposed to polyphonic) synthesizers, yet the pitch of this note is easily identifiable.

I've found that why playing this album in the past, regardless of the type of equipment I was using, as long as my speaker system reached low enough into the bass I could feel the effect of the bass pedals in my gut, and the window frames in my room would shake. But I couldn't necessarily determine what note was being played. With the Nagra Classic Preamp in the system, I felt the bass notes in my gut, the window frames would shake, but I could also hum along (a few octaves higher, obviously) the notes Mike Rutherford was playing while standing on one foot, the other manipulating the pedals of his bass synthesizer. The bass notes enveloped my entire body, I could feel the bass notes on my exposed skin as well as in my gut. While these bass pedals were being played, I could also clearly hear other instruments that had large amounts of bass energy, such as Mike's Rickenbacker bass guitar, and the lower toned drums on Phil Collin's drums, taking no heed to the subsonic notes that the bass pedals were playing. This has as much to do with the rest of my system as anything else, of course, and the fact that I was spinning the 200-gram Classic Records pressing issued more than fifteen years ago.

Some may think that because the Classic Preamp is a tube unit  that one could assume that its midrange would be the star of the show. Of course yes, this linestage has "a great midrange", but it does this without anything that would resemble what one might consider a typical "tube sound", at least not in the negative sense of the term. In fact, of the best things about this midrange was how much I did not notice it. What I mean by that is that in my listening notes there weren't any comments directed towards any of the frequencies in particular, but rather how this linestage reproduced music, in particular how well it aided in making my system reproduce musical instruments on the records that sounded not like the musical instruments, but like the musical instruments being reproduced. This also might have more to do with the Classic Preamp's transparency, and how it allowed the source components to do what they do best. Remember, at the time of the audition period in my system feeding this Nagra component were some particularly fine front-end components, including but not limited to not only the highly rated (and rather pricey) EMM Labs DA2 digital-to-analog converter, and also the massive (and even more pricey) Analogue Artisan A-1 Series turntable. Plus, the Classic Preamp's outputs were connected to a pair of monoblock amplifiers built in Binghamton, New York that pump out 600 Watts each into a pair of ultra-transparent Sound Lab electrostatic loudspeakers.

The Nagra Classic Preamp was in good company. The Nagra Classic Preamp did its job by selecting my source components, providing an appropriate amount of gain to their signal, and passing that signal to the power amps with as little alteration of the musical signal as possible. It's a known fact that this is much more difficult than it seems. The Nagra Classic Preamp does this so well that I didn't notice that it was doing it, other than the sonic feature I mentioned before -- that recorded music sounded more like music than I was accustomed to when using other preamplifiers in my system.

I'm a sucker for just about any LP released on EMI during their "golden era", that is, from the late 1960s to the mid to late 1970s, most with the prefix ASD in the catalog number (or SLS when it's a box set). Andre Previn and the London Symphony Orchestra recorded a bunch of LPs for EMI back then, including a number of works by Dmitri Shostakovich. I played a few of them during the Classic Preamp's stay, and these albums were an excellent tool for displaying the traits of this preamplifier, along with the bonus of being able to enjoy my favorite at the time, Shostakovich's Eighth Symphony. I bet you thought I was going to mention that I listened to the very popular Fifth Symphony conducted by Previn, didn't you? As much as I like his 5th, lately I've been drawn to his much more tragic 8th. The recording quality of this symphony is just as good and might even be a bit better than the more popular 5th, and even though both works were easily able to demonstrate the sonic traits of the Classic Preamp I've been discussing, this time, his Eight won out.

The midrange on this record sounds fantastic, the lower strings and violin section make major statements in many parts of this dark masterpiece, sometimes I would close my eyes and I would feel as if I could see into the recording, enabling me to view it with my mind's ear each section of the orchestra that Shostakovich highlighted during his often complex and angular orchestration. When it came to drawing my attention to the sonic features of the Classic Preamp, it also didn't hurt that Shostakovich wrote this work for a very large symphony orchestra, which includes a sizable woodwind section with some unique instruments, including cor anglais, soprano clarinets, E-flat clarinet, bass clarinet, and contrabassoons, along with all of the others that are the usual suspects that make up this section of the orchestra. I might not have been able to point out each one of these instruments as the thick slabs of sound enveloped me during the more intense moments, but this hardly mattered.

The treble that was reproduced by the Classic Preamp was also highlighted when I played this LP, not only because of the winds, horns, and strings upper registers, but because of the host of percussion instruments that Shostakovich used in this symphony, including tambourine, cymbals, snare drum, triangle, xylophone, and tam-tam. But the sound of the Classic Preamp was more than just having an excellent treble, midrange, and bass -- it managed to have both the benefits of tube and solid-state in one component and managing to do this without drawing attention to anything but the music it was reproducing. It was able to separate the instruments and sounds with any source I used, digital or analog, and this was mainly due to the Nagra's ability to create a dynamic distance between these sounds.

When two or more instruments took up the same space in the Classic Preamp's huge and drawn-to-scale soundstage, and these sounds were being reproduced at the same volume, they still were separated in space. This is a feature that is difficult to describe but easy to hear, and those who have heard this characteristic in their own systems will agree. But it is as if these sounds, whether a solo violin, percussion sound, a guitar solo being played through a stack of Marshall amps, or a sound produced by a synthesizer, there was not only air around each instrument, but also around and behind it, creating not only a sonic space between it and the other sounds, but distance between the other sounds that could be measured. The Classic Preamp made it so the music that came through it was source-less, that is, just "there". This was another attribute that was difficult to explain but easy to hear. In the past I've sometimes described this sound as having an "organic" quality, a sound that can only be described as "music", sound that elicits emotion without having to be analyzed or explained. It creates a connection between the electronics reproducing the signal and the listener, the listener not caring how or who is reproducing this music but only that it exists in the form that those who created it had intended.

Nagra VFS
Nagra offers to those who purchase a Classic Preamp their Vibration Free System (VFS). This is an accessory that consists of two bases, one fitting above the other which is designed to eliminate mechanical vibration    caused by other components in one's system or generated from airborne sources. Each half of the VFS uses different absorbent material designed to absorb a specific range of mechanical frequencies. The VFS comes with three spiked feet which attach to the bottom of the Classic Preamp, and then the spiked component is placed on the VFS. The feet are made of ARCAp, a non-magnetic copper-nickel-zinc non-ferrous alloy. The feet are fitted with Delrin tips, a compound that is used very often in turntable construction because it properties that are similar to metal and plastic in terms of strength, hardness and stability, but is much easier to work with. Since the Classic Preamp is a tube component, it is especially sensitive to vibration, and that is why I requested a VFS. This was about half-way through the review period.

I'm not sure if I heard a difference when using the VFS since I was using the Classic Preamp while it was on a shelf of my Arcici equipment rack, which is quite immune to the effects of vibration. I have not doubts that the VFS will work in lowering the effects of vibration in certain situations, as Nagra has "a reputation of precision engineering an audio excellence that have been the trademark of the Nagra brand for over 60 years", and the performance of their Classic Preamp bears this out. However, I have no doubts about the other added benefit of the VFS -- that it improves the cosmetics of the Classic Preamp, as it looked much better with the VFS attached than without.

MPS / The Classic PSU
Although the internal power supply of the Classic Preamp has proved itself to be very effective in my listening tests, Nagra also offers its Multiple Power Supply (MPS). Briefly, the MPS is designed to be used with up to four Nagra components. It is component-sized outboard power supply that offers "constant noiseless power" to one's Nagra components. It also has an optional Lithium-Ion (Li-ion) battery to deliver a more "pure" power source. As have used battery-powered components quite a few times, I can vouch for the batteries effectiveness in improving the performance of the component. I plan to add to the Classic Preamp the MPS later and will report back on my findings.

Conclusion
It was a pleasure using the Classic Preamp. Not only did it improved the sound of my system immeasurably, it was a pleasure to operate, and matched my system perfectly. One of the features of the Classic Preamp is its switchable gain. On its front panel is a small toggle with the option of +0 dB and +15 dB. Even though the amplifiers I was using for this review have more than enough power, my speakers love lots of gain, and so the Nagra's switch remained at the high gain setting. This changed the sound quality of the Classic Preamp not one bit, the only difference was its volume.

I'm racking my brain searching for something negative to say about its performance, sound quality-wise or otherwise. I can't. OK, perhaps some might not love its remotes atypical shape, somewhere between Captain Kirk's phasor and large rabbit's foot. I accidentally dropped it a few times, but that might have been because my brain has been hard-wired to use a more conventional rectangular stick. But I'm picking nits here. To all that want the very best in preamplifier design, and especially to those who have a system that can appreciate its ultra-luculent and musical sound, I give it my highest recommendation. Yes, it's a bit pricey, but definitely worth it.

Specifications
Type: Stereo preamplifier 
Frequency response: 10 Hz to 50 kHz (+0 / -0.5 dB)
Dynamic Range: >125 dB (Gain at +12 dB)
Minimum input level to reach 0 dB (meter) 0.28 V rms (Gain at +12 dB)
Maximum input level to reach 0 dB (meter) >25 V rms (Gain at 0 dB)
Crosstalk: >85 dB
Total harmonic distortion (THD) <0.01% at 1 kHz out, no load
Input impedance: 50 kOhms
Output impedance: 6 Ohms
Vacuum Tubes: Two 12AX7 / ECC83 and one 12AT7 / ECC81
Power supply: 115 V or 230 V AC input
Inputs: Balanced XLR and unbalanced RCA 1 to 4
Outputs: Two sets balanced XLR and one pair unbalanced RCA
Dimensions: 12.2" x 10" x 3" (WxDxH)
Weight: 10.8 lbs.
Price: $17,600, with VFS option adding $2300

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