D’Agostino Momentum Stereo Amplifier

Flanked by the wall of monstrous amplifiers here for evaluation, the compact D’Agostino Momentum stereo power amplifier stands out from the pack. As the Hammond organ solo in Mighty Sam McClain’s “Too Proud” crescendos from the softest touch to full force and back, the sound, awash in texture and decay, takes me to that magical place where I’m truly convinced that I’m not just listening to a hi-fi system; this is real music unfolding in front of me.

Even at high listening levels, when pairing the Momentum with my reference KEF Blades, the dual indicator needles of the amp’s sexy lime-green power meter barely come off of their rest stops—and I pause, wondering if perhaps they are defective. This amplifier seems to have an endless reserve of power on tap, along with thunderous but controlled and defined bass response. Remember, this amp is from the same man that gave us Krell amplifiers in the 1980s—amplifiers that redefined what solid-state amplification could achieve.

Luckily, I still have an original Krell KSA-50 on hand for comparison (covered in the Old School column in issue 53), and I enjoy jumping in the time machine to revisit the inception of this mighty amplifier. All of the Momentum’s core attributes are here in the KSA-50. While Krell amplifiers always received much fanfare for their prodigious bass response, the KSA-50 also has a smooth, grain-free top end, with a wealth of inner detail to boot. Comparing these two amps is a lot like comparing an early Porsche 911 to a current model; driving them back to back brings home the level of refinement that’s taken place over the years.

He’s Done It Again

The D’Agostino monoblocks, released about two years ago, caused quite a stir in the industry. Even at $55,000 a pair, they made believers out of everyone who heard them. The Momentum Stereo, priced at $30,000, makes this performance available to a more prudent and space-conscious audience. Best of all, should you decide that the extra juice of the monoblocks is necessary, you can send your stereo amp back to the factory and have it converted to a monoblock. Then just add the second monoblock, which makes for and easy and cost-effective upgrade from the single-amp solution.

At the risk of deterring you from spending more money with Mr. D’Agostino (unless you have terribly inefficient speakers), I will say that you may never need to go with the monoblocks. All of the speakers at my disposal are in a sensitivity range of 86 dB to 90 dB per watt, and no matter how far I crank the volume, I never hear even the slightest hint of compression or clipping. And I do listen to my music fairly loud on occasion.

Going back to the recent LP remaster of ZZ Top’s Tres Hombres, I do just that—and as great as the massive drums and guitars sound through the Momentum, the telltale bit comes at the end of the track, when Gibbons’ guitar gently fades over a bed of wind chimes tinkling in the air. Wow! The incredibly detailed three-dimensional perspective again fools me into thinking I’m listening to an actual musical object floating in space. But the real test comes when I play “Sam the Wonder Dog,” from the first Stereophile test CD, which has the neighbors’ dogs howling away!

We could go on and on about all the technology that makes the Momentum so special—from the unique design of its heat sinks to its two big banks of 69-MHz output transistors—but you can read all of that on the D’Agostino website here.

I should note that our review sample spent time at a few trade shows, so it arrived fully broken in and ready to go, so I can’t comment on how long a fresh amplifier takes to sound like the review sample.

A Sight to Behold

Don’t let the diminutive form factor of the Momentum fool you. This slender amp is all business, weighing nearly 100 pounds. We normally don’t hesitate to pop the top off of most amplifiers, but the Momentum’s case has no exposed screws, so rather than risk a highly embarrassing call to D’Agostino, I decide to settle for pictures of the amp’s gorgeous exterior.

And gorgeous it is. The entire chassis, save for the side-mounted heat sinks (machined from copper billet), is all CNC machined from solid aluminum. Chances are high that you will be spellbound by the refined-steampunk look of the Momentum.

Rocking SBTRKT’s self-titled album brings the listening room alive with major beats that punch you in the stomach, yet the finesse of the Momentum creates a massive ball of sound that feels like multi-channel audio emanating from only two speakers. With the music approaching club volumes, the Momentum’s needles now move in earnest, inching halfway up each side of the power meter—but there’s still plenty of juice on reserve. Again, the KEF Blades crank out heavy, controlled bass that you feel as much as you hear.

Highly Sophisticated

Much like the sports cars of the early 1980s, most power amplifiers were one-trick ponies that don’t offer anywhere near the same amount of finesse as today’s best designs. What makes the Momentum amplifier so dandy is that it offers no compromise in any aspect of sound reproduction or even day-to-day use. Thanks to some new power-management circuitry from Mr. D’Agostino, the Momentum only draws one watt when in idle mode—which is less than an iPhone charger!

D’Agostino doesn’t list a spec on power draw at full output, but being a Class AB design (a radical departure in itself for Mr. D’Agostino), this amplifier probably only draws about 500 to 700 watts from the AC line, which means that it doesn’t require anything out of the ordinary in terms of power. After hours of play at relatively high volumes, the copper heatsinks get warm to the touch, but nothing like any of the Class A amplifiers at my immediate disposal.

But again, all the technology under the hood of the Momentum stereo amplifier is lost on this writer the minute that the music begins to play. After months of listening to the Momentum with a plethora of ancillaries, I find it completely without fault of any kind, on any level.

Listening to the hardest rock or the subtlest solo vocalist, this amplifier delivers power, punch and nuance, all with equal aplomb. The best amplification components I’ve experienced make it impossible to identify them with your eyes closed. The Momentum is one of these rare amplifiers that will leave you scratching your head, with a non-existent sound signature that resembles neither tubes nor transistors. The Momentum is in very rare territory indeed.

Grooving on “Twisting with James,” from the Dr. No soundtrack, the drumming stays right in the pocket, while the full-on surf guitar and sax easily occupy their own private space in the soundstage. Cranking both sides of Judas Priest’s Screaming For Vengance on LP usually leaves me desperate for some earplugs, but the Momentum reproduces the layers of driving lead guitars so effortlessly, keeping the voicing of Glenn Tipton and K.K. Downing’s guitar distinctly different. This is something that many amplifiers cannot achieve, especially at high volumes. It’s metal at its finest.

Spinning a pile of Motown records, settling on some Supremes, I find it intriguing to hear how much detail lurks in these classic tunes. The Supremes’ collaboration with the Temptations, “I’m Gonna Make You Love Me,” is fantastic; it not only reveals the vocal stylings of these legendary artists, but it also puts some meat on the bones of the presentation. This tune now has a solid bass line that was not apparent before.

The percussive sounds at the beginning of Tom Waits’ “Town With No Cheer” hang in the air effortlessly, as the bagpipes fade to Waits’ young, vibrant voice, which keeps a subtle distance from the harp and accordion playing in the background. This sense of space is what separates the Momentum from lesser amplifiers, this delicacy again making it so easy for the amplifier to just disappear and become a conduit for whatever music is being played.

Geeky Bits

While the Momentum definitely benefits from adding premium cable, as does any great amplifier, it is not overly cable sensitive when it comes to power or signal cables. However, its highly resolving nature allows the differences between various cables to come through loud and clear. The Momentum does not prove highly sensitive to the various power-line conditioners on hand, either—a testament to the high integrity of its power supply’s design. The Momentum does experience a slight increase in high-frequency smoothness and liquidity when plugged into either the Running Springs Maxim or the IsoTek Super Titan conditioners (both via a dedicated 20-amp circuit), but this effect is nowhere near the dramatic difference experienced with some even more expensive amplifiers.

Perhaps the only piddly complaint with the Momentum is that, because it’s such a compact amplifier, the rear panel reveals a sparse complement of connectors: 12-volt triggers, a pair of XLR inputs and a pair of copper binding posts that do not allow for banana plugs. It’s all tucked in fairly tight quarters, so those with massive speaker cables may need to rethink their termination. I would highly suggest adding the stylish aluminum base that D’Agostino developed for the amplifier. The base will assist in cooling and get the amplifier up off the floor or shelf, providing much easier access to the speaker terminals.

Around front, the power switch hides underneath the crown jewel of the Momentum, the magnificent power meter, which is backlit in bright green. If there were ever a place that the term “audio jewelry” applied, it’s here. I suspect that this amplifier will be as compelling to look at years from now as it is the day you remove it from its padded flight case.

The day of $30,000 amplifiers is here to stay. While some will whinge about the price, the question remains: Does this amplifier provide performance and build quality in keeping with the price asked?

To that ultimate question, the answer is unquestionably yes. We’ll even stick our necks out and say that the D’Agostino Momentum stereo amplifier is possibly one of the best amplifiers available at any price. If you don’t believe me, I suggest you take one for a test listen.

Momentum stereo amplifier

MSRP: $29,000 (silver); $31,500 (black)



Analog source AVID Acutus Reference SP turntable    TriPlanar tonearm    Lyra Atlas cartridge
Digital source dCS Vivaldi stack
Phonostage Indigo Qualia
Preamplifier Audio Research REF 5SE    Burmester 011    Robert Koda K-10
Speakers GamuT S9    KEF Blade    Dynaudio Evidence Platinum    Focal Maestro Utopia  Sonus faber Guarneri Evolution
Power IsoTek Super Titan
Cable Cardas Clear

Peachtree Audio deepblue Bluetooth Music System

Some audio fans crave a stereo experience courtesy of multiple components. Of course, more equipment means more money. Plus, each component needs its own power cord, interconnects and shelf space. For those who seek a smaller, more portable home-audio experience—or for those who simply want a more manageable music system outside of their primary listening room—a single-box wireless audio product, like the Peachtree deepblue, is a great solution.

The elliptical cabinet of the deepblue measures 8 inches tall, 6 inches deep, and 16 inches long, and it is slightly flared at the bottom. The unit weighs a substantial 16 pounds. This form factor makes this Peachtree portable and it can bring a lot of sound to any size room.

The deepblue’s facade comprises a black plastic case with a metallic grille, which extends the full width and height of the unit. The result is slightly cheap looking, but those who believe sound is more important than appearance will easily forget the unit’s aesthetic. The grille protects the forward-facing drivers neatly packed behind it. On each side of the unit resides a small tweeter placed above a midrange driver. These four drivers flank a centered 6.5-inch woofer. Thanks to the deepblue’s onboard amplifier, the package can put forth a hefty 200 watts.

Peachtree’s design for button controls on the deepblue is a model of simplicity. There’s a power button nestled between a volume up and a volume down button. That’s it. And that’s all you really need. The deepblue’s remote control enables a few additional and helpful adjustments. In addition to selecting standby power and volume from the remote, the user can adjust the unit’s bass output for various types of music or preference. It’s also nice to have the ability to adjust bass to compensate for placement near a wall or inside an enclosure, which sometimes result in bass “loading,” or boominess.

Connecting the Equipment

The only wires a user needs to contend with for the deepblue are the power cord and the mini-jack auxiliary stereo connector. This 3.5-mm input allows users to connect an external source manually. But for those who want to scale down to just the power cord, deepblue also accommodates Bluetooth pairing with devices like an iPad, iPhone, or a computer, as long as those devices support A2DP Bluetooth audio. The remote also enables source switching so that the listener can choose between the connected auxiliary source and the Bluetooth source from the comfort of a listening chair.

Bluetooth setup is very simple: activate Bluetooth on an external music source; press and hold the deepblue’s power button for five seconds (or just press the remote control’s “Pairing” button for two seconds); and then the unit’s light flashes slowly and initiates the coupling process. Peachtree notes that the deepblue has a maximum Bluetooth range of around 30 feet, although obstructions and walls can reduce that distance.

Those who opt for Bluetooth and commit their phone as the music source need not worry about missing a call while enveloped in the listening experience. The deepblue recognizes the call and will fade and stop the music, alerting the listener. Once the call is complete and disconnected, the unit resumes playing music. It’s a marvelous capability and it works flawlessly.

Testing Bluetooth functionality on an iPhone 4 with iOS7, I find that the process is just as easy and seamless as advertised. After holding down the “pairing” button on the remote at 15 feet away, the deepblue flashes its blue LED and “Peachtree BT” appears among the connection options on my phone. After I touch that source listing on the phone and after a brief pause, the phone connects. Selecting some music on the phone produces immediate and good quality sound from the Peachtree.

With a Bluetooth source, the paired communication enables the remote to advance or pause the song playing. So, when listening to the Police’s album Synchronicity, it’s easy to skip the song “Mother” before it has a chance to claw its way out of the speakers. When I test this functionality, the remote has some trouble interfacing with my iPhone 4’s controls, but I’m sure newer mobile devices will have less of a problem.

Diving In

Being accustomed to a large stereo reference system, I reset my expectations for the single-box deepblue. After much listening, I’m mighty impressed with what’s achievable for the $399 cost of the unit. Even in my large listening space—17 feet deep by 20 feet wide by 10.5 feet high—the deepblue puts out plenty of sound to fill the room without any perceivable strain. Whether the source is a Bluetooth-paired phone with songs ripped at 128 kbps, an iPod with lossless files or a CD player connected to the auxiliary port, the sound remains very good. The better the source material the more the Peachtree rewards the listener.

Given the deepblue’s design as a compact, single-box unit, a listener can expect inherent limits in stereo imaging and soundstage. All musical elements sound compressed together; however, considering that limitation, the deepblue offers a reasonable soundstage.

The deepblue’s portrayal of music remains generally relaxed, but it is not without punch. Throughout hours of listening to many types of music, stridency is limited. High frequencies, in some cases, sound a bit rolled off, but there’s still plenty of treble to satisfy most listeners. Vocals are nicely rendered and very present in the mix, but some vocal test tracks expose a bit of sibilance. Regardless of music type—be it classical, jazz, electronica or rock—the balance of instruments remains very well portrayed.

Even through a Bluetooth connection, the cymbals on the Dave Brubeck Quartet’s “Blue Rondo à la Turk” offer a surprising amount of sparkle and decay, which appropriately jump out from the overall mix. Playing Big Bad Voodoo Daddy’s debut album tests the Peachtree’s ability to handle a multitude of simultaneous instruments and vocals—and it does not disappoint. It’s still easy to pick out each instrument sonically, despite the limited soundstage separation.

Exploring the Depths

As mentioned earlier, the bass adjustment is a lot of fun to experiment with. While a small physical box has some limitations in the lowest frequencies, the Peachtree is definitely no slouch. Jean Michel Jarre’s album “Rendez-Vous” leads in with a hefty, synthesized bass roar. With the deepblue’s bass turned up, even at 15 feet away, the sound causes the sofa to vibrate slightly and unexpectedly.

On some tracks, I enjoy listening with the bass accentuated a bit, though some boominess and muddiness is occasionally the result. The overall sonic presentation is tighter with a solid, stable surface beneath the unit. For testing, I place the deepblue on a 26-inch-tall spiked speaker stand, allowing the tweeters to hover near ear-level. For home listeners, some placement experimentation is worth the time to find the balance that best serves a user’s needs and preferences.

Hidden Treasure?

The Peachtree deepblue is not a system intended for audiophiles seeking the greatest level of stereo reproduction, imaging and nuance. It is designed to be a simple, plug-and-play solution to fill any room with music. It meets its intended goals very well, and then some.

At $399, the deepblue offers very good sound for its price point. Notable benefits are authoritative bass, enough horsepower to play at substantial volumes and solid rendering of all music types. This Peachtree does all of this with great user-friendliness. Plus, a listener can place it anywhere an electrical outlet is near. For those seeking a flexible, unobtrusive and turnkey audio solution, do yourself a favor and check out the Peachtree deepblue. You might find it to be a perfect fit.

deepblue Bluetooth Music System

MSRP: $399



Digital Sources HP Desktop Computer with JRiver Media Center 19     iPod Gen 7    iPhone4 with iOS7,    Audio Research CD3 MKII    Light Harmonic DaVinci DAC
Cables Jena Labs Valkyrie and Symphony interconnects    Jena Labs Twin 15 speaker cables
Power Conditioner Running Springs Audio Haley
Power Cords Cardas Golden and RSA Mongoose
Accessories Mapleshade SAMSON racks and shelves    ASC TubeTraps    Cathedral Sound room-dampening panels

The Beatles – The Beatles Stereo Box Set

The Web has been abuzz for more than a year about EMI’s latest attempt to extract more oil from a well that we keep thinking will eventually run dry: the Beatles catalog. Yet the label manages to surprise us again, with a newly remastered set of vinyl.

Most retailers are discounting the new box to somewhere in the neighborhood of $350-$375, breaking the cost down to about $27 per title; single albums are forthcoming. Not crazy money in audiophile terms. These record sound much better than anything you’ll ever buy from Friday Music.

Unfortunately, Beatles lovers and audiophile collectors got thrown under the bus in one aspect, as the powers that be chose 24-bit/44.1kHz files for mastering instead of the high-resolution 24-bit/192kHz files used for editing. When the box sets reached the buying public last week, and seemingly everyone who was anyone–and a lot of those who aren’t–promptly declared it rubbish.

Of course, once completist collectors are removed from the equation, as many of them won’t take the damn things out of shrink wrap anyway, who is the real audience for these records? If you are lucky enough to have mint, low-stamper UK, German, or Japanese pressings of these classics, you already have the grail. Even if EMI had produced these new records from 24/192 masters, they would have still sucked in comparison.

Sure enough, when evaluating a few tracks from Sgt. Pepper and Magical Mystery Tour on my $100,000 analog front end, the new records fall short. This, however, is akin to comparing a New Beetle to a vintage ’67 VW Bug with 1,500 miles that’s either been lovingly restored to perfection or, better yet, is completely original and NOS. It’s a pointless argument.

Even my favorite go-to set of Beatle albums, the blue BC-13 box, now fetches a thousand bucks in mint condition–if you can find one. When judged against these, the new records still lose a bit in top-end air and ultimate bass punch. Say what you will, but I like the stereo mixes.

Taking to the streets, I scoured a few of my local record stores (we’ve got quite a few here in Portland) and found used Beatles albums in horribly disfigured condition, with tattered covers and vinyl surfaces that I wouldn’t play on a Close and Play. Average cost? About $15, some as high as $30. Most were American Capitol pressings. A rubbish situation, and you won’t do much better on eBay.

Changing it up from my megabuck system to something more real world (a Rega RP6/Exact combination, playing through the vintage Nakamichi receiver and JBL speakers we used in our room at the Rocky Mountain Audio Fest), the new records sound pretty damn good.

The physical presentation of the box also qualifies as very good. Again, we are dealing with copies of copies, and the amount of money required to print these at a level commensurate with fine art is prohibitive. Contrast is picked up and some tonal scale lost, but again, when comparing to my mint BC-13 box or a scuffed American copy in the used bin, the new box comes out ahead. The jewel is the 252-page book, offering an engaging overview of the Beatles history. The records themselves sport a mixture of Parlophone label, Capitol label, and Apple label IDs–a fun touch for those new to Beatlemania. Not historically correct, but informative.

Early purchasers have mentioned sporadic pressing problems, but the set we received for review (purchased from SoundStageDirect.com) is free of defect. Hopefully, issues remain limited to the first out of the chute. A gentle hand is required to remove the tightly fit outer slipcover, but I’m guessing that if you can’t remove it without damage, you’re not much of a hit with ladies, either.

Seasoned audiophiles, record collectors, and music lovers often forget that new people discover the Beatles and vinyl, every day. A majority of them could care less about first-stamper this or German pressing that. If you have rare, original pressings of these records, relish the fact that you own a precious part of music history. You will never be happy with these pressings.

Those of you beginning your vinyl journey, whether music lover, budding audiophile, or both, the current Beatles box will prove a great addition to your collection. Who knows, they may lead you to get caught up in all this madness to seek out a few mint originals for your collection someday.  -Jeff Dorgay

EMI, 16LP Box Set

PrimaLuna ProLogue Premium Stereo Power Amplifier

So what exactly makes this a premium PrimaLuna product?  Like all products from the Dutch brand, the ProLogue Premium Premium Stereo Power Amplifier has a certain aesthetic appeal: a gunmetal-colored finish, which wouldn’t be out of place on an AMG Mercedes, set off by an anodized-aluminum faceplate (available in silver or black).  Also like the rest of the company’s lineup, the ProLogue Premium stereo amp offers serious levels of performance—this is where the amp’s premium designate becomes apparent.

Popping off the bottom cover reveals ceramic tube sockets and Nichicon and Solen capacitors flanked by premium resistors, along with newly designed output and power transformers.  Wiring is all point-to point and meticulously done by hand, which is one of the reasons PrimaLuna amps have earned such a high reputation for their reliability.  All this precision comes wrapped in a somewhat compact package that weighs nearly 50 pounds, and has an MSRP of $2,299.

Hassle-Free Tube Power

PrimaLuna amplifiers have long been known for their Adaptive AutoBias circuitry, a PrimaLuna trademark that makes traditional tube biasing a thing of the past.  This design allows a wide range of tubes to be used in the output sockets:  KT88 or EL34 tubes work equally well—every ProLogue Premium Series amplifier comes with either set of tubes installed.  (The KT88s produce 36 watts per channel; the EL34s produce 35 watts per channel.)  The new premium version of the amp adds a switch on the side of the chassis, allowing you to optimize the amplifier to your choice of tubes, in order to achieve the lowest possible levels of noise and distortion.

I’m immediately struck by the lively sonic response that the ProLogue provides, with a quick, organic and natural sound that spans all frequency ranges.  This amplifier always feels ready and able to take on whatever you can throw at it—which is exactly what I did.  The ProLogue Premium eliminates the hassle of owning a vacuum-tube-powered amplifier.  It even has a PTP circuit (for Power Transformer Protection) that will protect the amp’s output transformers, should you have an accidental, catastrophic tube failure, which can happen with today’s tubes.

PrimaLuna has updated the front-end circuitry for this amp, which now uses 12AU7 tubes instead of the 12AX7s in the company’s earlier amplifiers.  The inveterate tweak-geek in me could not resist fooling with those 12AU7s, even though the amp sounds great with stock tubes.  New old stock GE tubes render a smoother top-end response, but offer a different listening perspective, as if I had moved back about five rows in the orchestra.  Next, a set of RCA clear tops (with side getters, for the tubeophiles in the audience) provides a big jump in frequency extension, as well as more transparency and a more palpable midrange.  Best of all, Kevin Deal, the owner of Upscale Audio (and the PrimaLuna importer) has a massive cache of these tubes in stock, so you can experiment at will; the 12AU7s aren’t nearly the cost of the 12AX7s. When asked, Deal said that he has “over 10,000 rare and NOS 12AU7s.”

Be aware, I achieved these results with my system; so don’t take them as an absolute, as results will vary on other systems.  But that’s the fun of an amplifier like this:  You can experiment as much or as little as you want—and we haven’t even talked about swapping output tubes.  Don’t forget to save those stock tubes just in case you find yourself lost in the vacuum-tube jungle.

Love at First Listen

Brian Bromberg’s closely miked contrabass in “The Saga of Harrison Crabfeathers,” from his Wood album, instantly confirms the level of full-bodied bass definition the ProLogue Premium provides.  In addition to the solid low-end response, you can clearly hear the creaking and groaning of the instrument, as well as the strings being plucked and slapped on the fretboard.  I’ve never heard this kind of resolution from a vintage Dynaco Stereo 70 (or modded variation on the theme).

Muddy Waters’ album Folk Singer proves a perfect midrange showcase for this amp, which places Waters’ voice firmly at center stage, while simultaneously revealing the ambience in the recording studio present on this intimate performance.  Perhaps the best showcase of any tube amplifier is its ability to convey the sultriness of the female voice, which is another test that the ProLogue Premium passes handily.  I listen to the entire disc of Renée Fleming’s Haunted Heart without pause.  The track “When Did You Leave Heaven?” gives Fleming and the accompanying guitar, courtesy of Bill Frisell, plenty of space without missing a lick of subtlety.

And Secondly

It’s usually a given that vacuum-tube amplifiers excel at revealing low-level detail and vocal tonality, but the ProLogue Premium performs equally well with larger-scale music.  Nelson Riddle’s Nice ‘n’ Easy: The Music of Nelson Riddle is a classic big-band record full of massed horns, which the ProLogue Premium sails through, keeping the horns sorted without becoming harsh or buried in the mix—impressive.

The acid test comes via the Minutemen’s “One Reporter’s Opinion,” from the Double Nickels on the Dime disc.  D. Boon’s AK-47-style guitar playing is present in all its force, Mike Watt’s fluid bass is easy to follow and drummer George Hurley’s seems to punch a hole in my forehead—the PrimaLuna delivers all of this while giving the track the precision and grit on the scale it deserves.  No matter how complex the musical selections, this amplifier does an excellent job keeping pace.

I’m a Fan!

I’m taken with this little but heavy amplifier, and can see why our publisher has been an advocate of PrimaLuna since day one.  This amp takes everything I throw at it in stride—always musical, always eager and always evenly balanced in overall presentation.  As with the other PrimaLuna products, the Premium stereo amp represents good value.  This is the perfect power amp for a music lover wanting to assemble a high performance system on a tight budget.  The ProLogue Premium is worth every penny.

I will say that one must be realistic when pairing the Premium with his or her speakers and listening environment.  Although the volume levels I’m able to achieve with this amp in my largish room are quite satisfying, 35 watts only go so far—even great watts such as these.  The amp does clip slightly when I get lead-footed with the volume.  To its credit, when the amp does clip, it does so with gentle compression instead of just falling apart.  To this point, speakers that are in the 90-plus-dB category will make for optimum system synergy in most rooms.

Additional Listening

By Jeff Dorgay

As Jerold mentioned, I’ve been listening to PrimaLuna amplifiers since the company introduced the original ProLogue One almost 10 years ago.  It’s almost like TONEAudio and PrimaLuna have grown up together.  That original amplifier is still in my family and, with a replacement set of power tubes, it keeps playing music on a daily basis without bother.

It’s been fun watching the PrimaLuna products evolve over the years into a more fleshed out line, with each model revealing more music than the one before.  Putting the ProLogue Premium stereo power amp through its paces is a joy, with the matching preamplifier and a few other examples I have on hand.  If you don’t need a built-in phonostage (and like your garanimals to match), the $2,199 ProLogue Premium Preamplifier makes for killer a setup with the Premium power amp.  The preamp is perfectly matched to the power amp electrically and stylistically, and pairing the two together will easily fool you and your friends into thinking you spent a lot more scratch on your system.  Many of my old-school buddies were having visions of vintage McIntosh in their heads, when I had this PrimaLuna combo connected to a mint pair of JBL L100 speakers.

Cranking up Judas Priest’s Screaming for Vengeance (on the matching PrimaLuna CD player we reviewed a few months ago) is a little slice of heavy-metal heaven—for a minute I was worried I might just blow up those JBLs, like I did back in the day.  The smooth sound of this PrimaLuna front-end package does not disappoint.
Another, more modern speaker that is a spectacular match with 35 watts per channel of tube power is Vienna Acoustics’ Mozart Grand.  The speakers have a 90-dB-sensitivity rating and a very gentle first-order crossover, but the ProLogue never runs out of gas when powering them.  And at about $3,500 a pair, the Mozart speakers won’t put you in the poorhouse.  Those on a tighter budget, consider a pair of Vandersteen 1Cs, which have the same high sensitivity, but are only $1,200 a pair.

Back when Kevin Deal and I sold mid-fi gear in stereo shops reminiscent of the one in the movie Ruthless People (1986), we used to describe gear as being more suited to rock or classical, etc., etc.  But the PrimaLuna electronics are a little bit of magic:  They play everything well, yet they inject just enough of that tubey warmth to make the bulk of your music collection sound much better than you’d expect it to.  This is a godsend for those having a mostly digital music collection, MP3s or CDs.

For this amp, I took the time to swap output tubes.  A set of super high zoot NOS 6550s or a new set of EAT KT88s, both of which will set you back about $1,500, but fear not, there are tons of great new EL-34 tubes in the $25-$50 range that sound fantastic. The extra midrange warmth and liquidity they provide will have you wondering if you ever need another amp.  And should a tube fail at an inopportune moment, the Adaptive AutoBias will even keep the amp purring along with a mixed set of output tubes. You’d be surprised at how many hardcore audiophiles have gone full circle back to the simplicity of an EL-34 amplifier paired with moderately efficient speakers.  This is an amplifier you can either start your tube journey with, or live with happily ever after.

With vintage Luxman, Marantz and McIntosh tube amplifiers fetching crazy money on the used market these days (not to mention their questionable reliability), make your life easy:  Put a PrimaLuna Prologue Premium between your speakers and just dig it.  You’ll be glad you did.

PrimaLuna ProLogue Premium Stereo Power Amplifier

MSRP:  $2,299



Digital Source PrimaLuna ProLogue Premium CD Player    dCS Debussy
Analog Source Rega RP6w/Exact    Monk Audio Phono Pre
Preamplifier PrimaLuna ProLogue Premium    VTL TL-5.5Mk. II
Speakers Lawrence Audio Violin    Dynaudio Confidence C1 II
Cables AudioQuest King Cobra    Furutech LineFlux and SpeakerFlux

Bob Carver Black Magic 20 Stereo Amplifier

To say Bob Carver is a legendary amplifier designer would be a major understatement.  Without going into historical detail, suffice it to say he has produced a few gems in his day.  And now it’s back to the future, with Carver again producing amps under his own name.  The Cherry 180 (reviewed HERE) and the Black Beauty 305 monoblock amplifiers have both received universal praise from reviewers and happy customers alike, for their build-quality, stylish good looks and plenty of power on tap.  But with the $2,100 Black Magic, Carver takes a different direction.

This small amplifier, model designation VTA20S, is finished in black with a “silver-fleck” chassis and brushed-silver trim.  It is outfitted with 12AX7B tubes for the input stage, and a quartet of EL84Ms for the output stage.  According to Carver, the “M” variant of the EL84 was selected because it has a higher plate-voltage rating, allowing for maximum power output within safe operating conditions.

Setting up the Black Magic is amazingly simple.  There is no need to bias the tubes, which is done automatically with one set of speaker binding posts, optimized for a 4-ohm load.  There is, quite interestingly, a volume pot at the top-front area of the chassis.  (More on that a bit later.)  I drive the Black Magic with a Rogue Ninety-Nine preamplifier for the bulk of my listening sessions, and in turn drive my Thiel CS2.4 speakers.

After giving the Black Magic ample warm-up time, I’m rewarded with startling clarity, a liquid-smooth midrange and, most impressively, floor-shaking bass.  Carver says that the amp is “conservatively” rated at 20 watts per channel—it definitely sounds more powerful than its published rating suggests.  For my review, I go directly from my Audio Research VS55 amplifier (rated at 50 watts per channel) to the Carver with no immediately discernible decline in dynamic performance, power output or bass quality.

The Black Magic’s imaging specificity is impressive, with little of the “tube haze” surrounding the vintage sound of the EL84 tubes.  The Black Magic easily handles music of any scale, including orchestral crescendos.  The Direct-Stream Digital SACD of Semyon Bychkov conducting Rachmaninoff’s Symphonic Dances is simply ravishing in the tone colors of the strings and woodwinds, and the full impact of the orchestra’s power is there in all its glory.  I am continually stunned at just how much of a wide dynamic swing this little amplifier can muster.

The sublime SACD pressing of the Moody Blues classic album, In Search of the Lost Chord, plays to all the strengths of the Black Magic.  The melancholy melodies and vintage arrangements on such tracks as “The Actor,” “Visions Of Paradise” and the album’s centerpiece, “Legend Of A Mind,” are breathtaking in their majesty.  Lead vocalist Justin Hayward’s voice is a holographic presence in my listening room, and the amp delivers more than enough resolution to hear long-buried recorded details—just the thing you call on a tube amplifier to perform.

Staying with the vintage vibe, the Carver brings sparkle and life to the iconic ’60s recordings by Smokey Robinson & the Miracles, from the well-mastered compilation, The Definitive Collection.  The Black Magic commands attention on such classic tracks as “Going To A Go-Go,” “The Tears Of A Clown” and “Mickey’s Monkey.”  The rhythmic incisiveness is top notch, with a keen ability to get a track moving.  This inner detail and delicacy is always a key factor with an amplifier based on the EL84 tubes, and the Carver has the best balance of new- and old- school sound that I’ve experienced in this genre.

Moving on to modern times, U2’s “Electrical Storm,” from The Best of 1980–2000 collection, simply rocks when playing through the Carver, which highlights the shimmering acoustic guitars, jagged electric lead lines, throbbing bass line and, of course, Bono’s passionate lead vocals.  On this track, all of the separate elements of the recording are made into an organic whole, providing some rare goose-bump moments.  The remix of “Gone,” from U2’s Pop album, is another standout track providing such moments.

An now, more about the amp’s volume pot I mentioned earlier:  Connecting the Marantz SA-11S3 SACD player/DAC directly to the Black Magic and adjusting the volume level directly from the amp provides additional transparency to the source and bass articulation.  The volume control has an excellent range of attenuation, never going past the 12 o’clock position.  Most modern line sources, like a CD player or DAC, output 2 volts, which is more than enough to power an amplifier with sufficient gain.  For those only utilizing a DAC and multiple digital sources, I suggest eliminating the linestage altogether—the Carver is that good.  However, for those using a linestage/preamplifier, I would leave the volume control at full, effectively taking it out of the circuit.

With the Black Magic, Bob Carver has done it again.  In addition to all of its positive sonic attributes, the Black Magic ships with a seven-year warranty on parts and labor, along with a generous one-year warranty on the tubes.  (Most manufacturers only offer 90 days.)  It is made entirely with point-to-point wiring in Carver’s Kentucky facility.  You can read more about Carver’s manufacturing process HERE.

While 20 watts per channel isn’t the solution for every system, a modestly sized room matched with sensitive speakers will deliver a rocking performance using this modern EL84 marvel.

Additional Listening

By Jeff Dorgay

Blowing the dust off of my Dynaco SCA-35 integrated amp reveals just how far Bob Carver’s classic design has come.  The vintage Dynaco is a pleasant listen, but switching to the Black Magic, even with vintage speakers like the JBL L26s, is a revelation.  Where the vintage amplifier has loose, flappable bass, the Carver is taut.  An equal paradigm shift is experienced in the upper registers—the HF roll-off that I’ve almost come to expect with this tube doesn’t happen, which is a testament to the quality Carver’s circuit and transformer design.

The only speakers in my arsenal that prove a challenge for this amp with heavier music are the Dynaudios, which have a somewhat low 84-dB sensitivity rating.  Thanks to a single-order 6-dB/octave crossover network, the speakers work well with the Black Magic, as long as not asked to play extremely loud—you can always pick up a second one, if need be.

Much like when listening to a top-notch mini-monitor, the Carver Black Magic excels at throwing a three-dimensional sound space that feels almost like wearing a gigantic pair of headphones.  It also delivers a tonal balance, falling more on the romantic side of the scale.  The Carver is certainly not vintage, but it does embellish slightly—for those using primarily digital source material, this should be a very good thing.

Lastly, to probe the absolute limit of the Black Magic, I insert it in my main reference system while finishing the review of the $120,000 Sonus faber Aida speakers (92-dB sensitivity).  This makes for a great showing, as the little amp is able to control these gigantic speakers incredibly well.

Andre and I agree:  If you’ve been wanting to try tubes, this is the perfect place to start your journey!

Bob Carver Black Magic 20 (VTA20S) stereo amplifier

MSRP: $2,100



Analog source,”Rega RP6 turntable    Exact cartridge    Lehmannaudio Black Cube phonostage”

Preamplifiers,”Rogue Audio Ninety-Nine    Conrad-Johnson PV-12″

Digital sources,” Marantz SA-11S3 SACD player/DAC    Logitech Squeezebox Touch    Meridian Sooloos Media Core 200/Rega DAC”

Speakers,”Thiel CS2.4    Dynaudio Confidence C1 II     Definitive Technology SM65    JBL L26    Sonus faber Aida”

Cables,”Darwin Cables Silver interconnects    Transparent Audio Super MM2 interconnects    Transparent Audio Plus MM2 speaker cable”

Power cords/conditioners,”Acoustic Zen Tsunami II power cables    Audience Adept Response power conditioner    Running Springs Audio Haley”


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