Einstein The Absolute Tune Integrated Amplifier
by S. Andrea Sundaram
I used to think that integrated amplifiers were only a bridge between the world of mass-market receivers, with their myriad bells and whistles, and a true high-end-audio experience. The majority of integrateds fit this description quite aptly. They are the workhorses of many budget-minded audio enthusiasts' systems -- offering good sound for the money. By keeping two related functions in a single chassis -- often using the same power supply -- a designer can save significant cost on everything from materials to labor to warehousing and shipping.
As I looked to move up from my first integrated, I began by considering separates, but, still being budget-conscious, I opted for another integrated amplifier of a more distinguished pedigree. The cycle repeated itself once again a few years later, and I ended up with another integrated. Separates were no doubt sexier and occupied more space in an audiophiles' dreams, but when it came time to spend my money, it was the integrateds that seemed to be the better value.
Einstein's grandly named The Absolute Tune is one of the highest-end integrated amplifiers on the market. At its $10,300 USD price, separates are far more common than integrateds, but what you don't find at this price level are separates from Einstein. A $10,000+ integrated amplifier is unlikely to match the performance of the $30,000 worth of separates, on which its design was based. However, the same efficiencies that apply at the budget end of the market are present at the very highest end. Might The Absolute Tune represent as great a value as other integrateds?
Einstein Audio is a small company, about a dozen employees, that released its first product in 1990. Though Einstein has only been distributed in the US since 2005, it is reassuring to know that the company has been around for 17 years, producing quality products that have been well received. Besides the integrated under review, Einstein's current product line includes a preamp, two power amplifiers, a CD player, and a phono stage. With the exception of the phono stage, all of Einstein's products use vacuum tubes in the design.
One of the advantages besides price of an integrated amplifier is that it requires less space than separates. The Absolute Tune measures approximately 17"W x 7"H x 15 1/2"D and weighs a hefty 40 pounds. Though of average size, The Absolute Tune is a stunning piece of industrial design in gloss black and polished stainless steel. It manages to look both high-tech and elegant. In fact, the aesthetic appeal of The Absolute Tune put all of my other components to shame, except my Michell Tecnodec turntable. The fit'n'finish aren't only impressive from afar. A closer inspection reveals extreme attention to the details of fabrication and assembly. A component at this price should be made to exacting standards, but not all similarly priced products measure up to those set by the Einstein.
What may strike you as odd with The Absolute Tune's appearance is the placement of the transformers at the front of the chassis and the tubes at the back. This arrangement was chosen for sound engineering reasons, not merely aesthetic ones. The power transformers are as far away from the audio circuitry as is possible in this single-box design, while signal paths are kept very short. Rather than placing the mains receptacle at the back of the unit, the designers placed it on the bottom front. To accommodate that placement, the entire chassis rests on four substantial columns that would probably cost a few hundred dollars if sold separately as footers. Aside from limiting your options in terms of aftermarket power cords, I can't see any negative aspect to this design choice.
On the front panel are two wide, shallow control knobs. The right knob controls volume, and the left controls source selection. That source selector knob moves in click stops and is referenced to relays which handle the actual source switching duties (to keep those signal paths short), and it turns when controlled by the remote -- very cool. The only other thing on the front panel is a display with three blue LEDs. The right and left LEDs click off when their associated channels are ready to play, while the center one remains on. Around the back, you will find inputs and outputs for the right channel on the right side of the chassis, and those for the left channel on the left. There is a grounding post in the center -- odd for an integrated amplifier without a built-in phono stage, but useful in solving some ground-loop problems. All of the inputs are high-quality, chassis-mounted RCAs. Each channel has a single pair of plastic-shrouded binding posts, into which the single spades at the ends of my speaker cables fit securely.
The Absolute Tune is a hybrid design, marrying a tube gain stage to a solid-state output stage. Such a design is often claimed to give the benefits of both devices -- harmonic richness and a sense of space from the tubes, high power and damping factor from the transistors. The design is fully balanced in the output stage, but single ended at the inputs. Having the design fully balanced from input to output would add parts, complexity, and cost, but the lack of a fully balanced signal path will deter some buyers. The Absolute Tune is truly dual-mono. Aside from the power receptacle and control knobs, you could cut this integrated amplifier in half and make two mono integrateds. Each of the power transformers looks substantial enough not to be out of place powering an amplifier of twice the rated power at a lower price point.
The Absolute Tune is rated to deliver 50Wpc into 8 ohms, and 85Wpc into 4. The damping factor is given as greater than 200. Even if you hadn't read the previous paragraph, these numbers would tell you that the output stage is solid state. The 96dB signal-to-noise ratio is quite high for an integrated amplifier, especially one employing tubes. THD at 1kHz is said to be a respectable 0.02%.
The tube complement consists of four 6922 dual-triodes. Tube-rollers will have no trouble finding stratospherically priced NOS replacements for this common tube type, but the more frugal audiophile can retube The Absolute Tune for as little as $50. In short, cost of ownership should be negligible, but those who wish to do so have ample room for tweaking.
The one specification that could be problematic is the rated sensitivity of 2V RMS. For an amplifier, sensitivity refers to the necessary input signal to achieve the rated output. A sensitivity of 2V is fine for a power amp, but high for an integrated. If you connect a source with, for instance, an output of 1V, even with the volume turned all the way up, the amplifier won't be producing its full rated power. The output of my Ayre C-5xe universal player is only 1V when playing SACDs, and I did run out of room on the volume knob when listening to some BIS recordings, wherein the average level was very low. The potential buyer should check the output levels of the sources he intends to use with The Absolute Tune in order to avoid a mismatch.
Frame of reference
I used The Absolute Tune in place of my own similarly powered Graaf GM-50 integrated amp in a system consisting of an Ayre C-5xe universal player and Michell Tecnodec turntable with modified Rega RB-300 tonearm and Shure V-15X cartridge for sources. Amphion Argon II speakers are my reference. Interconnects were QED Silver Spiral from the Ayre player, and JPS Labs Superconductor from the Trigon Audio Vanguard II phono stage. Speaker cables were DH Labs Q-10.
All equipment was plugged into an Equitech Son of Q balanced-power isolation transformer. The Absolute Tune ships with a high-quality stock power cord, but Brian Ackerman, of Aaudio Imports, the company that handles Einstein electronics in the US, sent along an Isoclean cord with the proper right-angle plug. The upgraded power cord did add an extra dose of clarity and increased transient speed a bit, but The Absolute Tune already did these things very well with the stock cord. It is nice to have the option of a very good upgraded cord, but, at an additional $1100, the Isoclean cord should not be considered essential.
The first thing you'll notice upon powering on The Absolute Tune is the utter lack of mechanical noise. Many pieces of audio equipment, even those that cost a lot of money, emit some hum from their transformers, but I heard nothing from the Einstein integrated. This quietness carries through to the near absence of electronic noise. With the volume turned all the way up, without any signal, I could hear only the faintest whisper of hum by putting my ear next to the woofer. Likewise, I only heard any hiss from the tweeter with my ear practically in the waveguide. Any sound present when there is no signal is distortion in the presence of a signal, so hearing almost no noise bodes well for the performance of The Absolute Tune. Although my speakers are of average sensitivity, the extremely low noise floor also suggests that the Einstein integrated would mate very well with high-sensitivity speakers.
The manual suggests leaving The Absolute Tune on for half an hour before listening in order to achieve the best sonic results. Although this integrated sounds respectable immediately after it is turned on, I found that a few hours of warm-up were necessary in order for it to sound its best. I took to turning on The Absolute Tune as soon as I got home from work, so that it would be ready when I wanted to listen later in the evening. The Absolute Tune's preference for being played warm continued throughout the review period and was not merely a consequence of some break-in period.
Heat was not an issue for The Absolute Tune -- it ran exceptionally hot. Yes, some heat was generated by the four 6922s, but the chassis was especially hot above the transformers and on the sides of the back portion (near the output transistors, I expect). While the manual makes no reference to the amp's bias, the amount of heat generated leads me to believe that the output stage is biased for more than a few watts into class A.
It's important to note that The Absolute Tune inverts polarity. You'll want to compensate for this at your source or speakers.
If there is one word that summarizes the sound of The Absolute Tune, that word is "clean." From a single plucked string to an entire orchestra at fortissimo, the Einstein integrated never introduced any of the graininess that is sometimes associated with solid-state equipment, nor did it obscure transients with the syrupy smoothness of tubes. It simply sounded as though I was hearing what was on the disc. By saying that The Absolute Tune's sound was "clean," I do not mean to imply that it was "sterile." Rather, it seemed to put as few artifacts between my ears and the recording as some of the best systems I've heard, regardless of price. This cleanliness did not result in a lack of emotion either. Music, whether vocal or instrumental, had character and nuance, never failing to draw me in, so long as the recording was up to the task. If anything, the clean portrayal of the Einstein integrated allowed those nuances to be heard even more clearly than through many other integrated amplifiers.
Rhythm and timing are vital components of involving music, and the Einstein excelled at both. The bass lines on the Andrea Pozza Trio's Sweet Lorraine [Venus TKJV-19154] were appropriately bouncy, propelling the rest of the ensemble along, and setting my toe a-tapping. Through other amplifiers, these bass lines can become less articulate -- without a precise starting and stopping point for each note. Precise timing is critical to appreciating the interplay between the musicians on this recording. You can tell that this is a group well accustomed to performing together, and they sound like a single unit. That is one of the things that I love most about this disc.
For the musician, timing is often more intricate and difficult to master, more so in playing jazz than other types of music. For any piece of audio equipment, it is equally difficult, and important, to follow more standard rhythms precisely. While I felt that jazz combos brought out this aspect of the Einstein integrated's performance most vividly, I also appreciated its exceptional sense of timing on classical and rock recordings. No matter the material, each note was in its proper place, and it lasted for the proper duration.
The bass range of The Absolute Tune was not only agile and articulate, but also as powerful and as extended as my speakers allowed. The bass drum that opens the "Kyrie" from Ramirez's Misa Criolla on José Carreras: The Golden Years [Philips 289 462 893-2] was executed with startling transients and substantial body. On some recordings I could even feel the bass notes hitting me in the chest -- quite an accomplishment from 6 1/2" woofers, and indicative of considerable power and control.
The top end of the Einstein's frequency range was free of grit or glare, and well extended. It was not quite as open and airy as I have heard from some other integrated amplifiers, though, and neither did it have as much sparkle in the highest frequencies as certain other components. This can sometimes come across as brightness; The Absolute Tune did not sound dull in the highs, but it didn't highlight them either. I personally would prefer a touch more shimmer in these frequencies, but I would not want to sacrifice the Einstein integrated's neutral tonal balance to obtain it. The Absolute Tune never caused me any fatigue, but for those who may be looking for a slight roll-off in the upper end, this integrated is not the one. For those who want clean, honest highs without any undue emphasis, The Absolute Tune would be an excellent choice. It walks a difficult line very well.
Perhaps due to its dual-mono nature, The Absolute Tune cast a remarkably wide and precise soundstage. Instruments were not only centered in the appropriate places, but, with well-made recordings they kept their proper proportions. The soundstage was less deep than I am accustomed to hearing, but it was still multi-layered and unflappable. What I found truly amazing was that the soundstage changed not at all when I raised or lowered the volume. Not only was the brass still behind the strings, but it was exactly the same distance behind the strings, no matter the volume level. I've heard other equipment keep what I thought was a consistent soundstage at different volumes, but The Absolute Tune set a new standard in this regard.
Along with the somewhat reduced sense of depth, I heard less of the hall surrounding the ensemble than I am accustomed to hearing. On Debussy's Pelléas et Mélisande Suite from the recording of the same name [DG 289 471 332-2], I heard a smaller, drier, recording venue through the Einstein integrated than through my own Graaf. I have never been in the hall where this recording was made, so I cannot comment on which presentation is more accurate. Some components can cause every recording to sound as though it was made in a well-damped studio. The Absolute Tune does not have this failing. What it does is convey each individual hall in a manner different from that conveyed by my reference integrated amplifier. However, those individual halls still maintain their relationships to one another in size and acoustics.
One of the characteristics that I associate with vacuum tubes is a wealth of harmonic information. It is the preservation of this harmonic information that allows recorded instruments to sound like their live counterparts. The Absolute Tune preserves much of the harmonic structure of instruments, but less than some other all-tube components. Instruments with less extended harmonic structure -- such as electric guitar -- sounded very similar to the way they do live, whereas some other instruments -- such as violin -- were not quite as believable. I should point out that making these distinctions is really splitting hairs, but a component of The Absolute Tune's quality and cost deserves to be compared to the very best that reproduction has to offer.
All things are relative
As I mentioned at the beginning of this review, high-priced integrateds might not be as ubiquitous in the marketplace as are their budget cousins, but neither are they scarce. My own Graaf GM-50, at $7500, is fair competition for The Absolute Tune. These two integrateds have similar power ratings, similar weights, and similar dimensions. They are both very well built, but the industrial design of The Absolute Tune is vastly superior to that of the GM-50. They also have some key differences in circuit design. The Graaf unit is all tube, relying on a pair of KT90s per channel. The GM-50 is also fully balanced from input to output, whereas The Absolute Tune only offers single-ended inputs. The Absolute Tune counters with its entirely dual-mono construction and exceedingly low noise floor.
So which integrated comes out on top? Overall, the Einstein has a focused and compact presentation, whereas the Graaf is a little more diffuse and grander in scale. The tonal balance of the Einstein integrated is a trifle lean, the Graaf a touch fuller. Either integrated amplifier is perfectly capable of handling any type of music, but their different perspectives lead some parings to be more synergistic than others. If you like large orchestral works performed in large halls or live rock concerts in big arenas, the Graaf GM-50 may be better suited to those recordings. If instead you prefer chamber music, jazz quartets in a studio, or a multi-tracked rock recording, then Einstein's The Absolute Tune may be more to your liking. As for someone like me who enjoys all of the above, I would be equally content with either one.
While some audiophiles might scoff at the idea of paying over $10,000 for a integrated amplifier, The Absolute Tune offers a level of performance that is commensurate with that hefty price. The fact that it does so in a compact and stunningly designed package is just icing on the proverbial cake. If you are more interested in sound quality than the amount of space you can occupy with your audio equipment, then I heartily suggest that you give this integrated from Einstein a listen.
Did I enjoy my time with The Absolute Tune? Absolutely.
...S. Andrea Sundaram
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