A visit to Nagra is a very special thing indeed. The factory is cleaner than a hospital, with highly organized workstations populated by happy and highly skilled workers calmly assembling some of the world’s finest audio gear. There’s almost a reverence about the place, and with the Montreux Jazz Festival nearby, there’s always plenty of access to fantastic live performances as an absolute reference.

On my last visit a few years ago, Nagra had something special in progress. The company’s engineers were just finishing the final prototype of a new vacuum-tube power amplifier—a push-pull design featuring a pair of 300B output tubes and producing 20 watts per channel.

“With the wideband output transformers designed for the 300p, [the amp] has incredible control for a 300B design,” explains Nagra’s Matthieu Latour. “And it will surprise you with the wide range of speakers it will drive.”

Surprise Indeed

Magic is more like it. Toward the end of the title track of Pat Metheny’s Offramp, as Naná Vasconcelos’ gentle, twinkly percussion bits intertwine with Dan Gottlieb’s delicate brush work, it’s clear that this amplifier is able to capture the essence of what fans of the 300B SET sound clamor for, while exhibiting plenty of substance and control. From the top to the bottom of the frequency spectrum, especially the lower end, it’s instantly obvious that this amplifier has none of the shortcomings that plague even the best SET designs.

Steve Rodby’s signature acoustic bass has major weight and texture through this amp; you can almost feel his hand run up the fretless neck as the notes glide out into the soundstage. This is even more spectacular when you consider that the 300p is not driving a high-efficiency set of horn or single-driver speakers, but my reference KEF Blades. Though fairly efficient, with a 90-dB-per-watt sensitivity rating, the Blades require an amplifier with current reserve and low-end grip—something the 300p provides with ease.

Massive Attack’s “Karmacoma,” with its deep, slippery beats, underlines how well the 300p can take control of the Blade duos eight total woofers, moving some serious air without the presentation becoming weak or smeared. An equally enjoyable performance is rendered with selected tracks from Deadmau5, Skrillex and Tosca. This compact amplifier delivers potent bass response.

Beyond Bass

Ellen Reid, the female vocalist behind the Crash Test Dummies, produced a solo album in 2001 called Cinderellen. Reid stretches out a bit further as a lead vocalist here and most of the tracks are grittier than typical CTD fare. On “Defense of the Wicked Queen,” the 300p achieves a perfect balance between her complex voice and the accompanying piano. The 300p is a master of pace and timing, allowing the Blades to disappear effortlessly into room.

Much of this is the result of the attention to detail that Nagra paid when producing the amp’s output transformers, which are wound in house at Nagra. The rest comes from the prodigious power supply that is the foundation for the 300p, which has a nearly 11-by-11-inch footprint and weighs 31 pounds. Fortunately, Nagra ships it with the output transformer modules packed separately to avoid damaging the amplifier during shipping. As is the case with every other Nagra product we’ve had the pleasure to own or review, no detail, no matter how small, goes unnoticed.

At $16,900, the Nagra 300p is not inexpensive. Those thinking in terms of watts per dollar are missing the gestalt of this masterpiece. In the context of products from, say, Shindo or Audio Note, the Nagra is an absolute bargain—and is produced by a company with 60 years of experience and a comprehensive support staff, ensuring your Nagra products will always be in top shape.

As Ella Fitzgerald coos “April in Paris,” the luscious midrange depth of the 300p rivets your attention to the musical performance, and when Louis Armstrong joins her on the latter half of the track, awash in texture and tonal richness, it’s so easy to forget about the gear completely and just dig this classic tune. And that is the essence of the 300p: It always gets out of the way and celebrates the music.

Nuts and Bolts

As mentioned earlier, the 10.9-by-10.8-inch chassis has the same form factor as many of the other Nagra components, such as the PL-L preamplifier, PL-P phonostage and the new Jazz preamplifier, which we are now reviewing. It’s a basic, classic look that never goes out of style and pays homage to the famous Nagra field recorders of years past. I’ll stick my neck out and postulate that you will either gravitate to the Nagra design ethos or you won’t. If you fall into the latter camp, preferring massive boxes with enormous rack handles, the 300p is not for you.

Those of you who do appreciate the compact elegance and performance that is Nagra will revel in the sound of this petite music machine, and I suspect that you’ll do so for some time. This is not an amplifier to purchase casually, only to sell on Audiogon three months later. Like a fine watch or a Leica camera, the Nagra 300p is a treasure—something to be handed down to the next generation. Viewed in the light of permanence, the purchase price becomes somewhat irrelevant.

The front panel of the 300p features a slightly modified version of Nagra’s famous modulometer, which displays power output, allows biasing of the output tubes and assists with setting the load factor to optimize the amplifier for the speaker load being driven.  All of this is quite handy and helps the owner get the most performance from the amplifier. The rear panel is equally Spartan, with user-selectable RCA or XLR inputs and output taps, suitable for driving 4-, 8-, or 16-ohm speakers.

Particularly interesting is the hybrid design of the 300p, with its solid-state input stage and power supply that work harmoniously, offering a wide bandwidth and incredibly low noise. Past pure-tube 300B designs we’ve auditioned have been on the noisy side compared to a push-pull EL34 amplifier, but the 300p is nearly dead silent when I press my ear up against the tweeter of the Blades—highly impressive.

Stepping up to the Focal Maestro Utopia speakers that have just arrived for review, with their 93-dB sensitivity rating, makes the 300p seem almost supercharged, with twice as much headroom on tap. But the amp really comes into its own with the 100-dB ZU Audio Soul Superfly speakers, which are able to coax near-stadium-level volume and dynamics out of the 300p’s 20 watts per channel. The ZU’s 16-ohm impedance provides a benign load, transferring power easily from amplifier to speaker.

Surprisingly, the 300p can still drive the 85-dB Harbeth Compact 7s to a very reasonable level without breakup in a small to medium sized room. The Nagra now seems worlds apart from my 9-watt-per-channel Wavac amplifier.

Quality First

In the end, it’s about tonal purity and richness. Just like the small dog with a big heart that acts like it’s a Labrador, the Nagra 300p feels like a big amplifier until it is pushed to its absolute limit, which will ultimately be determined by your room and speakers.

I’m able to fool more than one guest into thinking that my 300-watt-per-channel Pass Xs 300 monoblocks are playing, when in fact the Nagra amplifier is what’s behind the music. The inner detail that this amplifier is able to reveal continues to impress, even after a couple of months of listening. Acoustic guitars have much more heft and resonance, with quicker attack and longer, more gradated decay.

Tube rollers will find intrigue with the 300p; however, the hand-matched JJs that are supplied provide an excellent balance of tonal purity, dynamics and extension at the frequency extremes. Should you have a few extra thousand dollars lying around and feel inclined, a recent vintage set of Western Electric 300Bs or EAT 300Bs, though expensive and tough to find, will take the 300p even further, providing even more inner detail.

Those wanting to simplify even further can purchase this amplifier as an integrated—called the 300i—for $21,250, eliminating the need for a linestage. Both units come supplied with Nagra’s VFS (Vibration Free System) platform to minimize interaction with the room environment. As with all other Nagra components we’ve used, the VFS is highly worthwhile, offering slightly quieter backgrounds and a more open soundstage, allowing you to peek even further into the musical picture. Perhaps it’s the large filament structure on the 300B tubes, but the VFS seems to make a greater improvement on Nagra preamplifiers than it does on others, so make sure and use it with your 300i/300p.

Regardless of which power tubes you settle on, if you have a pair of speakers with the necessary sensitivity for the Nagra 300p to offer enough dynamic range, this can certainly be your destination amplifier—and become the heirloom that the Nagra engineers intended.

Nagra 300p amplifier

MSRP: $16,900 ($21,250 for the 300i integrated version)

www.nagraaudio.com

Peripherals

Analog Source	AVID Acutus REF SP turntable    TriPlanar tonearm    Lyra Atlas cartridge
Phonostage	Indigo Qualia
Digital source	dCS Vivaldi stack
Preamplifiers	Nagra Jazz    Audio Research REF 5SP    Robert Koda K-10
Speakers	KEF Blade    Focal Maestro Utopia    Zu Soul Superfly
Cable	Cardas Clear
Power	IsoTek Super Titan

Nagra tends to make revisions to their product mix slowly, yet when they do it’s usually pretty major.  Their new Jazz preamplifier is the perfect example.

Just in case you are wondering, PSA stands for Pyramid Stereo Amplifier.  If you were like me and were drooling over those cool pyramid-shaped monoblocks from Nagra a couple of years ago, this is the next step in their product line.  The PSA delivers 100 watts per channel, as opposed to the 200 watt per channel PMA monoblock amplifiers and is priced at $6595.

If you want an amplifier that not only sounds great but is a show stopper, along the lines of a Ferrari Enzo, the PSA is the ticket.  I guarantee anyone that sees this in your home and has even a passing interest in aesthetics will be intrigued by this amplifier that can easily pose as a piece of modern artwork.  Everyone that saw it in my studio was fascinated by its stunning good looks.

I first saw the PSA at the Rocky Mountain Audio Fest in October, where the head of U.S. Sales for Nagra, John Quick was showing it off with Nagra’s new CD player and a new pair of Verity Audio (another favorite of mine) Rienzi speakers in a huge room.  The PSA had no problem driving these speakers as loud as I needed to hear them.  I made it a point to drag each one of the TONE staffers in attendance down to the Nagra/Verity room to hear this system!

As someone who grew up with giant amplifiers from ARC, Krell and a few others, I definitely went through massive amplifier phase of my audiophile life.  Granted, I worship great sound above all else, but when I can get great sound in a beautiful package it’s a huge bonus.

Setup

The PSA is not a terribly large pyramid, with a base of 15” x 15” and about 10” high.  It weighs 35 pounds, so you can actually think of it as your personal pyramid.  All kidding aside, this is a serious amplifier and though it possesses a switching power supply, it is a traditional audio amplifier, not Class D.

It will run comfortably on a 15 amp circuit, as it only draws 500 watts at full output. It features a pair of WBT binding posts on the rear panel along with a pair of XLR input connectors.  Nagra is kind enough to supply a pair of RCA adaptors, so if your system does not have a balanced input you are covered.  Please note, in the interest of keeping a compact rear panel, there is only the single pair of balanced inputs.

As our vintage columnist Kurt Doslu likes to say, “Don’t play catch with this one!”  However, I liked the shape so much; I actually put the PSA up on a pedestal.  I had an old concrete pedestal that looked like a column from the porch of one of the houses in Gone With the Wind, but this was not the optimum setup for the ultimate sound quality.

I had great luck using the PSA on a large Symposium Ultra platform that I often use as an amplifier stand.  Once connected to my Aesthetix Callisto Signature, we were ready to begin listening. My test unit had already had some hours put on it at the RMAF, so I can not accurately tell you how long one takes to break in; this one sounded great after two days of continuous play.  The rest of my system was rounded out with the Penaudio Serenades, Wadia 581 and the AVID Volvere turntable with a Sumiko Celebration cartridge installed.  I used a pair of Cardas Golden Reference interconnects with XLR termination and left the PSA balanced from the Callisto with excellent results for the majority of the review period.  I tried it both ways, but with the Callisto, could not hear a difference between the two.

Due to the close proximity of the speaker binding posts, I would suggest having the ends that go to your amplifier terminate with banana plugs.  I did manage to get some spade lugs in the terminals, but if you are looking for the most aesthetically pleasing setup, go for the bananas, it looks much tidier.

Lurking underneath the cool pyramid top panel is a set of jumpers to adjust the input sensitivity for the PSA.  You have a choice of 1V or 2V sensitivity.  My Callisto has a lot of gain, so I chose the 2V setting and that was perfect, keeping maximum volume right around the 12:00 position on the volume controls, just how I like it.

Does the sound live up to the fashion forward design?

Definitely.  I was very impressed with what I had heard at the RMAF, so I figured if they could get sound that good at a show, it would be considerably better in my more reasonably sized room and I have not been disappointed.  If I were to sum up the PSA in only one word, I would call it precise.  Ah, but it comes from Switzerland, so why would you expect anything else but precision from the Swiss?

To expand this definition a bit more closely, what I noticed immediately about the PSA is that it has a very dynamic sound, but never out of control.  The highs are extended without being exaggerated or grainy.  The bass has weight and texture, but you will never mistake this one for a Krell amplifier, either.  It’s just right.

If you are an audiophile that wants an amplifier that is very tonally accurate and has the punch of a solid state amplifier over tubes, this is one to put on your short list. (especially if you are a person that is design conscious)

Some people will make fun of this amplifier for having a tiny blue LED for power output and a tiny red LED to indicate clipping in the lower right corner of the front panel.  I say it’s a lot of fun and a very useful device.  But fear not, there is a switch beneath the amplifier under a small cap to turn the blue level LED off of you prefer. If you had to judge clipping by ear, you would be melting tweeters by the bucketload, because on the rare occasion that I did see that red LED light up, I was listening to music WAY TOO LOUD and it sure didn’t sound like the amp was going into clipping at all.  I also found the gently pulsing blue light coming from the base of the pyramid to be very soothing.

As I was in the middle of the Charlie Hunter interview while working on this review, I listened to the PSA with a lot of jazz in addition to the whole Charlie Hunter catalog. The PSA always did a fantastic job with revealing the most minute details and the trailing edges of percussion instruments.  Cymbals had great air as well as attack on Charlie’s first album Bing, Bing, Bing!  Not to worry though, when things got a little bit beefier on his current release, Copperopolis (especially the first cut) this amplifier did not flatten out.  Taking this groove to its ultimate conclusion, I went for broke, put Joe Satriani’s The Extremist (back in the day, Charlie used to take guitar lessons from Joe…) in the player and really cranked it up.

Even with very dense rock guitar music, the PSA held its poise and did an outstanding job of preserving that precious space between the notes.  Exceptional quality from a solid state amplifier indeed.  Then I sharpened all my razor blades.  Just kidding.

Very neutral…  just like Switzerland

The really handy thing about a power amplifier that has this neutral of a sound is that you can do your system tuning elsewhere.  Because my Callisto is a bit on the slightly warm and slightly wet side of the presentation, for me it was the perfect match to the PSA.  I did try it with a number of different preamplifiers, but I kept coming back to the Callisto with this one.  I haven’t had a chance to sample the excellent Nagra PL-L or PL-P linestages yet (which are both tube units), but again I really enjoyed what I heard at the RMAF, so watch for a future review.

Some of you may have the burning question as to whether 100 watts per channel is enough.  Always a tough call, but I think that in most cases it should be more than adequate. It depends on the side of the room and what speakers you are pairing it with.  The 87db Rienzi speakers were playing in a room that was 22’ x 26’ (with an 11’ drop ceiling) and the sound was very big and involving, so I would think in a moderate sized room with speakers in the 87-90db range, you should have more than enough power to spare.

My main listening room is 16’ x 24’ and I never ran out of power with the PSA with my 87db Penaudio Serenades, or the 84 db ACI Sapphire XL’s.  The only speakers that did give it some grief were my Apogees, but they give almost every amplifier grief due to their 82db sensitivity and 3 ohm load.

A very interesting alternative to the box

In my book, the Nagra PSA’s performance justifies its price.  Add their legendary build quality and outstanding mechanical aesthetics and you have a pretty interesting little amplifier.  If your listening requirements demand good sound, high quality and intriguing looks, this is the amplifier for you!

Nagra PSA amplifier

MSRP: $6595

www.nagraaudio.com

Peripherals

Preamplifiers	Conrad Johnson ACT2/series 2    Aesthetix Callisto Signature
Speakers	Tetra 506 Custom    Penaudio Serenade    DeVore Gibbon Super 8
Analog Sounce	Avid Volvere w/SME V arm and Sumiko Celebration cartridge    BAT VK-P10SE phono stage
Digital Source	Wadia 581
Interconnects	Cardas Neutral Reference
Speaker Cable	Cardas Neutral Reference
Power Cords	Running Springs Mongoose
Power Conditioning	Running Springs Jaco
Vibration control	Finite Elemente Pagode Signature Rack with Cerepucs and Cereballs   Symposium Ultra Platform and Rollerblock Jr.s

Swiss hi-fi manufacturer Nagra built its reputation on the ability to produce high-quality audio components in very compact casework. The company has continually honed its engineering and design skills, making every speck of space in pro audio gear count. Such expertise has resulted in consumer gear that looks very similar to pro gear.  Indeed, when I visited Nagra’s factory last summer, the MSA amplifier was in its final design stage. Prototypes sat on the table, along with another new amplifier that uses 300B vacuum tubes.

Unfortunately, with its “bigger is better” philosophy, the U.S. market has been a bit reluctant to embrace Nagra. Nothing could be more shortsighted: Nagra gear often outperforms the stuff in the large boxes. We’ve used quite a bit of its gear as reference components over the years, and the sound quality has always been first rate. The MSA power amplifier is yet another example of the firm’s engineering prowess.

The current MSA amplifier utilizes a single pair of power MOSFET output transistors and is completely symmetrical from input to output, featuring only a pair of XLR input connectors. Should you need single-ended RCA inputs to accommodate your preamplifier, Nagra supplies a pair of Neutrik adaptors in the boxs. The amplifier also has a pair of switches that adjust input sensitivity to 1V or 2V for maximum output. It’s a handy feature, especially if you have an older preamplifier that doesn’t have a lot of gain, or if you’d just like to optimize the volume control range of your preamplifier. The MSA is also designed to be used as a bridged monoblock, so listeners requiring more power can easily add a second amplifier and double the power output.

Requiring the same amount of rack space as the Nagra PL-L preamplifier (11 x 9 x 4.6 inches), VPS phonostage, or CDP CD player, the $11,750 MSA takes advantage of Nagra’s VFS Vibration Free Support platform to further improve sonics. Unlike the pyramid-shaped PSA amplifier, rated at 100 watts per channel and outfitted with an LED display to indicate power and clipping, the MSA adds the familiar Nagra modulometer power indicator along with a red LED to indicate clipping. These touches prove very useful, especially when playing heavier music, as the MSA does not sound harsh when driven to modest levels of clipping.  An optional cover is available to hide the heat sinks, but they are such a functional piece of modern art, it’s a mystery as to why anyone would want to cover them up. A familiar rotary switch used for on, off, mute, and “auto” functions rounds out the styling cues.

Initial Impressions

At just 21 pounds, the MSA is easy to unpack and set up. Thanks to the gigantic heat sink located on top of the amplifier, it runs cucumber cool. Even when pushed hard with heavy metal favorites, it barely got warm to the touch. The MSA does not require much space to keep it within operating limits.

My review sample already had some hours on the clock, but my experience with past Nagra gear has been that it only requires 50-100 hours of break-in time. Much like any solid-state amplifier, the MSA opens up and sounds its best after being powered up for a few hours, and can be left in the “on” mode all the time, or the “auto” mode where it will slip into standby mode after a few hours. In the interest of being green, the MSA draws only one watt of power in standby mode.

Top, Bottom, and In Between

Having lived with the Nagra PSA power amplifier for a few years, it’s fair to describe its “sound” as extremely neutral. The PSA adds or subtracts little, if anything, from the presentation. This characteristic may be good for some. But for anyone looking for a bit of tonal embellishment, it may not serve as a proper fit. I’ve always preferred the sound of the PSA with the PL-L tube preamplifier, as the latter claims an ever so slight warmth to its presentation, making the two a highly enjoyable and musical combination.

While the MSA stays true to the Nagra philosophy of signal purity, there is an additional dose of signal purity and delicacy to the presentation. It might be due to the single pair of output transistors. Currently under review, the First Watt M2 also uses a single pair of MOSFET output transistors and has a sonic signature that’s not unlike the best vacuum tube SET amplifiers I’ve experienced. The difference with the MSA? It possesses the low-level detail of the world’s finest SETs, yet also maintains the grip and control associated with a great solid-state amplifier. An outstanding combination, it underscores my philosophy that, with solid state, you can have it all.

Granted, some users will need the extra bit of power that the PSA brings to the table. My reference GamuT S9 speakers have an 89db sensitivity rating, and unless I played fairly compressed rock music (for example, Def Leppard’s Pyromania) I rarely pushed the MSA to its limits. Even when cranking the band’s “Rock, Rock (Till You Drop),” I remained impressed at the ease the MSA exhibited, even with its little red LED almost solid in appearance. The Nagra owner’s manual does not list the latter as a “clipping indicator,” per se, but as a warning that the output stage is passing more than 9 amps of current. I can push the PSA harder, but it was not as composed at the limit as the MSA. For those with more refined musical taste, the MSA should provide more than enough juice.

Balanced in all aspects of performance, the MSA excelled with pace and reproduction of inner detail. When listening to DEVO’s “Blockhead” from Duty Now For the Future, the underlying synth riff never got buried in the mix, as it’s wont to do with lesser amplifiers—especially during the chorus, when the band members yell “Blockhead!” Should classic DEVO not be your liking, Keith Jarrett basically achieves the same effect as he sings along in a trademark disjointed manner while playing piano.  During one of his improvisational bursts in “No Moon At All” from the 2010 duo album Jasmine, Jarrett’s voice floats right above the keys as it does when you hear him live. Since he uses a standard Steinway on the performance, it was easy to compare the tonality between the recorded instrument and my Steinway. The MSA displayed perfect tonal realism with acoustic instruments.

Furthermore, Charlie Haden plays bass on Jasmine, underscoring the MSA’s quick transient attack and delicacy. You can hear every move of Haden’s fingers sliding up and down the neck of the bass. And while the MSA was long on texture, it did not run out of steam when asked to produce prodigious bass, either. Playing deejay and spinning club-music favorites from Kruder and Dorfmeister, as well as the recent Hotel Costes 14, featuring some great tracks by Tosca, I was stunned at how well the diminutive amplifier controlled the woofers on my reference speakers.

But what takes the MSA into another realm is its ability to resolve subtle spatial cues. No matter what my choice of program material, I always managed to hear those little sonic treats that only come to life on the world’s finest amplifiers. An extra layer of guitar here, one more overdub there: These are the things you either forget about when using a lesser amplifier or, your brain attempts to fill in the gap. But when you hear them through your speakers, you know you are indeed listening to something special.

As it did with the other Nagra components with which I’ve paired it, the VFS platform ($1,925) added more clarity to the MSA’s overall presentation, most notably on low-level acoustic passages. Admittedly, the VFS did not make as dramatic of a difference with the MSA as it did with my VPS phono preamplifier, no doubt due to the vacuum tubes in the VPS being more sensitive to outside vibration. I highly recommend first getting intimately familiar with the MSA and auditioning the VFS at a later date.

Style and Performance

If you are looking for a high-performance music system that needs to fit in a compact space, I can’t suggest the MSA highly enough. This one is a precious jewel, offering a level of refinement only heard from some of the world’s best (and most expensive) solid-state power amplifiers. Adding the PL-L preamplifier makes for a genuinely formidable combination. And while 60 watts per channel isn’t everything to every audiophile, if you have a pair of speakers with the efficiency to optimally operate with this level of power, you will likely find the MSA an enchanting wonder.

Nagra MSA Power Amplifier

MSRP: $11,750  (VFS Platform, $1,925)

www.nagraaudio.com

Peripherals

Analog Source	Rega P9/Shelter 501II    Audio Research REF 2 Phono
Digital Source	dCS Paganini Stack    Sooloos Music Server
Preamplifier	Burmester 011    McIntosh C500
Speakers	GamuT S9    B&W 805D
Cable	Cardas Clear
Power	Running Springs Dmitri