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The Tact Audio 2150 Amplifier

The Road to Audio Nirvana Has Been Rerouted!

Clement Perry

October 9, 2003

Specifications

Power: (RMS) 2 x 150W / 8 ohm, 2 x 300W / 4 ohm
Output current: (peak, per channel) >50 A
Signal-to-noise ratio: ( A-weighted ) >110dB
Dynamic range: (20 Hz - 20 kHz) >130dB
THD+N: (all power levels 20Hz-20kHz) <0.01%
Digital resolution: 16-24 bit Linearity (-120dB) +- 0,2dB
Dimensions: (WxHxD) 450x98x420 mm
Weight: 18 kg / 37 lbs.
Price: M2150 $4,900.00; S2150 $4,400

Address:
201 Gates Road, Unit G
Little Ferry, New Jersey 07643
Phone: 201/440-9300
Website: www.tactaudio.com

Of all the audiophile components available today, I've never seen a product that's so loathed and beloved as Tact Audio's digital products. Digital was supposed to be the perfect sound when it was introduced a couple of decades ago. With all the advancements duly noted, audiophiles contend that vinyl still rules. They argue vinyl is analogue and digital is a facsimile thereof. Digital today, thanks in part to yesterday's pioneers like Forsell, Wadia, Accuphase, and Theta, helped dispel problems associated with early digital sound: hard, antiseptic, cold and uninviting. Today's new digital mavens such as Ed Meitner of Meitner Labs, Zanden Audio's Mr. Yamada, Electrocompaniet's Per Abraham and Radimir Bozovich of Tact Audio-the subject of this review-elevated digital technologies still further.

My first and quite vivid memory of Tact Audio began when they debuted the Tact Millennium, the worlds first digital amplifier at the '97 Stereophile Show. Shortly thereafter, Tact introduced the world's first room correction preamplifier in the Tact Model 2.2 (which I subsequently purchased). The Tact 2.2 served as my longstanding reference (if you've ever heard what this gizmo has done in my room, you'd know why). Until, that is, the long awaited Tact 2.2X, a much more sophisticated version replete with digital ins and outs, replaced the original.

Also new is their complete reworking of the Millennium amplifier in the less expensive Tact M2150. Costing $4,900 (less than half of the Millennium), the 2150 is also the first "true" digital-audio amplifier since other digital or Class D and Class T amplifiers use analog inputs before converting them to a digital waveform, then back to analogue. The Tact 2150 employs the pure digital Pulse Wave Modulation (PWM) amplification technique. PWM amplifies a digital signal and links it to the loudspeaker directly upon conversion to analog.

"Essentially," says Tact, the hundreds of active and passive components usually required for amplification are simply not here." This means, by conventional methods, the 2150 is not an amplifier at all. It is a D to A converter with enough power (current and voltage) to drive speakers directly. Unlike the many dozens of parts that exists in conventional amplifiers, there is only a single coil and capacitor performing a 60 kHz, second-order low-pass filter, after the D to A conversion in the Tact 2150 using Tact's exclusive, proprietary PCM-to-PWM "EQUIBIT" technology. EQUIBIT, developed by Toccata Technology of Denmark, reduces the digital signal lengthwise to the speakers.

The Tact 2150 is as feature laden as a Swiss Army knife. Multiple inputs (five digital and three analogue) qualify this digital dynamo as an integrated design in the most unconventional way. Built under the same roof as the still highly lauded but discontinued Tact Millennium, the Tact 2150 is a highly evolved version based on the same principals but is 25 lbs. lighter and $5k cheaper while boasting greater resolution capabilities with the help of sophisticated 24-bit/192kHz digital to analogue converters. For more technical information please visit Tact's website at www.Tactaudio.com.

Turn Me On

One of the many superior benefits of the Tact M2150 digital amplifier over analogue ones is that it operates close to 95% efficient and thus, does not run hot. The 2150's lack of heat sinks helps keep this amplifier light and its appearance lithe. Don't be fooled by the ripples that run along its sides; they were designed more for aesthetic appeal rather than heat dissipation. The 2150 features a zero feedback design and, at full volume (voltage), the power supply is a full 58 volts, equal to 150 Watts into 8 Ohms. To decrease the volume, the output voltage of the power supply is also reduced. This means that the volume control offers no active circuitry, which by the way, has been proven as an ideal method for excellent volume control when Ed Meitner used this method in his fabulous BiD in years past. Additionally, due to the voltage modulation used to control volume, the 2150 is purported to be impervious to clipping.

Physically, the 2150 looks like any Tact product with its large and omnipotent master wheel that serves as both its volume control and company's greatest spokesman. The "M" in M2150 stands for Master version because it employs a separate volume control, while the $500 less expensive "S" or Slave version, designed to go in tandem with Tact's preamps, does not. Mine arrived with the finely brushed black aluminum fascia (silver is optional). In terms of physical layout, the Tact 2150 looks pretty clean and simple, given its capabilities. Below the Tact Audio insignia, located on its upper left corner is the power button. Digital and Analogue selection toggle buttons are located on the left flank while the right side is balanced out by the master volume and mute buttons. A mere five buttons hide the Tact's labyrinth of sub-menus located via its remote control.

Depressing the Tact 2150 power switch illuminates its front panel display that reads "Loading System…5…4…3…" counting backwards to zero before its main status screen appears. It is here at the main screen that you can begin to understand how sophisticated and unconventionally designed this amplifier actually is. Input selection (1 through 8) is also visible via the front panel. Input selected will be displayed by a corresponding status screen that indicates: Input selection, Master level (in decibels), Input sampling frequency, and Master Level Volume in big bold LCD numerals that are easily visible from my listening seat 10 feet away. Sub-menu features such as: Balance, In-Out, Polarity, Delay, Crossover, ADC (optional analogue to digital converter), Display, REM (remote), COMM (communication), and ADDR (address) are all located with the toggle of the remote control. When necessary, each of these sub-menus allows for even greater flexibility and control. For example, when I opted for a second 2150 to vertically bi-amp my Ascendo System M loudspeakers, all I had to do was the grab the remote control, find the sub-menu's COMM (communication) control, and program each 2150 to output left and right channels separately. This programs the 2150's to perform like monoblocks with 300-watts per side.

The Tact 2150's rear panel closer resembles a digital-to-analogue converter but with speaker terminals. Three analogue inputs (two single-ended, one balanced) are sequentially allocated on its upper left, while five digital (three RCA S/PDIF's one AES/EBU, and one Toslink S/PDIF) are located beneath. All digital inputs support PCM audio data with sampling rates from 32kHz to 96kHz/16 to 24 bits. AES/EBU and RCA/coaxial inputs support a 192kHz sampling rate. One digital output serving as a pass-through comes as standard when using more than a single Tact 2150-as I am becomes imperative. When analogue usage is selected digital pass-through is disabled.

Intimidating? Yes. Hard to use? No!

Setup consisted of sitting each 2150 atop Kevin Tellecamp's Silent Running Audio component racks, while all AC contaminants were being fed through the Shunyata Research's HYDRA AC distribution center via all their accompanying Anaconda AC cords. All cabling for this was done using the fabulous and expensive Analysis Plus Gold cables strapped to the new and even more exciting Ascendo System M loudspeakers. AP's gold is just that, and I admit I was shocked by its performance more than its price. And at $5k per six-foot run, or $2k per meter, they're neither cheap nor affordable.

I must state for the record that the Bel Canto designed Tripath Technology taught myself, contributor Stu McCreary, and Dan "The Man" Dzuban, a lot about what to expect from digital amplification. This amplifier still stands as a reference by which all others should be judged. It proudly stood as a reference of mine for more than two years, with many much more expensive amplifiers finding their way back to their place of origin with a "sorry, I'll pass" sticker attached to them instead of "how much."

Tact-ical Assault on the Senses

What I heard via a full run of Analysis Plus digital link directly feeding the TACT 2150 was nevertheless staggering to my ears. This level of resolution I wasn't quite expecting. There exists a quality that is as immediate as well as it is astounding in the areas of silence, transparency and naturalness. Never, in my experience, has my system sounded this quiet. I'm talking dead quiet with your ears on the tweeters. No hissing at all! More unnerving, however, was what became available via the TACT 2150's digital signal from my couch ten feet away. Digital, I thought, wasn't supposed to sound this natural and, well, analogue-like. Those were the exact words I murmured to myself the very moment I put on Dizzy Gillespie's "Gillespiana CD" [Verve314519809-2]. I'm not certain if you're familiar with Manteca but I've got to admit, I wasn't as familiar as I thought after hearing through the TACT 2150.

First, there is the unmistakable freedom from artifice. A peculiar clarity overtook the music unlike anything I've encountered-digital or analogue-beforehand. Dizzy Gillespie's Gillespiana is a 22-piece big band directed by Argentinean Lalo Schifrin, that features jazz legends such as Clark Terry and Ray Barretto. Recorded in 1960 when panning too many instruments into one channel was probably considered an art form, needless to say, there is a lot to hear on this CD-literally. What I heard literally caught me off guard. Secondly, when you have dozens of instruments blaring the same chord and melody simultaneously, it's very difficult, if not down right impossible, to differentiate distinctions between the French horn, tuba, saxophone, trumpet and trombone. Yet, amazingly, somehow the TACT 2150 recreated this brass section as individual instruments. More than ever before I could make out each instrument at the very same time out of the corner of the soundstage.

Armed with a greater sense of validation than previously available, thanks in part to such great products like the Ascendo loudspeaker and Zanden products, I just couldn't believe how good the Tact 2150 actually performed. This digital dynamo revealed more nuances, hinted at more gradations, captured more of the music's ebb and flow, and boasted more micro and macro dynamics while intimating more of what was on this CD than I would EVER have thought possible. Especially from a digital product!

From the very top of the frequency extreme, say 17 kHz (measured) down to about 40 Hz exits a cohesiveness and synergy that allowed me to hear the delicacy of a softly plucked harp and the thunderous effects of a mallet striking a tympani simultaneously. On Reference Recording's "Requiem" [RR-57] CD, track seven entitled Pie Jesu, featuring the soprano Nancy Keith (a long time favorite of mine), revealed underlying bass notes from the very powerful Lay Family Concert Organ and this beautiful soprano in a delicate balance that never before sounded more authentic. Ditto bassist Charlie Hayden and guitarist Pat Metheny's performance on The Moon is a Harsh Mistress from on their Grammy-winning Beyond the Missouri Sky CD. I would also feel derelict in my duties if I didn't include Muddy Waters' classic CD Folk Singer. This blues standard never sounded so good. Jacintha's Here's to Ben, proved to me why everyone should own this soulful CD. Lastly, one of my favorite releases is from the Chesky brothers, aptly entitled Entre Amigos. The wonderfully rich and tropical sound of Brazilian music is a happy addition to my much-needed Antonio Carlos Jobim collection-especially after my return from that enchanted country only a few days before. This latest release features songtress-guitarist Rosa Passos and legendary jazz bassist Ron Carter performing in a collaborative effort that is as tight and rhythmic as it is refreshing and soulful. CD after CD, genre after genre, whether Classical, Big Band, Jazz, R&B or New Age, through the Tact 2150, it simply didn't matter. The music that comes through via a digital coax cable is, literally, what is on the disc in all its glory-or in many cases-all of its warts.

You Want the Truth? You Can't Handle the Truth!

As delightful as the Tact 2150 sounds, it doesn't come perfect, nor shall I say without my personal quibbles. However minor they appear, they are valid points discovered only after many months of intense listening sessions. The first of my quibbles: because there exists so little filtering between the signal path and the loudspeaker, there's little chance bad or half- decent recordings can sound good. As a result, many CD's didn't sound as good as I originally thought through the Bel Canto eVo2. On the contrary, I discovered that the eVo2 didn't bring to surface all the warts on each of my CDs, which was a good thing if you like your recordings to sound good. Worse, what do you do after you discover classical recordings don't possess that warm fuzzy feeling analogue amps provide, while jazz recordings sound better than ever? Talk about being in a catch-22. I've always wanted the truth, and felt intuitively that the 2150's pros far outweighed its cons. Moreover, synergy-wise, attempting to discern the situation as a software issue rather than a hardware one wasn't easy either. What's a law-abiding audiophile to do?

Flip the Script… Add tubes!

It's pretty much the gospel truth that tubes are superior in the areas of bloom, three-dimensionality, soundstage and palpability. Feats that, however euphonically conferred, or even-order distorted, produce the most convincingly lifelike playback this reviewer's ever heard. Just imagine the virtues of adding to those wonderful traits, the amazing transparency, relaxed presentation, tonal perspicacity, and the super-low noise floor that seems to be the very embodiment of the 2150. As you are very well aware, this hobby is built around synergistic combinations. Enter the Zanden Model 5000 digital to analogue converter (review forthcoming). Here is a standard Red Book (16/44) DAC, that offers nothing in the way of upsampling, and lists for an astounding $10K. Yet, this standard DAC's capabilities of naturally rendering the music's crux betters anything I've heard thus far from an external processor-yes, reducing my mighty Electrocompaniet CD player to transport duties (and it is a damn good one at that). As good as the Tact 2150's digital circuits are via the 2.2X preamp, or straight from the Electrocompaniet's digital output, ultimately matching it with the Zanden, for this audiophile, proved to be a synergistic match that just couldn't be denied.

For the first time, the possibilities of what is best about tubes and digital became evident. No more slushy sounding bass thanks to the Tact 2150's speed and great damping abilities. No more hints of stridency in the high frequencies thanks again to the legendary traits tubes are known to bring to string tone. I could go on and on but I think you tube lovers know what I'm saying. I am certainly a believer and am now using the Tact 2150 with the Zanden Model 5000 Mk III. Am I compromising the best digital has to offer by adding analogue back into the chain? I honestly don't think so. But the most important question that I believe should be asked is: am I finally able to get the ultimate in musicality I was hoping for when I started in this hobby? I would have to answer: Absolutely!

The Tact 2150 proved to me what is possible in digital amplification today. Its transparency and natural sound surpassed any amplifier I've reviewed to date, besting the incredible Bel Canto eVo2, my former reference. For me this marks an alternate route on the road to audio nirvana. Any amplifier for less than $5k is a bargain these days. To have an amplifier that conjures up fond memories of what I've always loved and loathed about single-ended designs and solid-state devices, discarding all that's bad, while keeping the good-all under a single chassis-is not only a feat, but at this asking price, a downright steal.

It would be, pardon the pun, tactless if I didn't add, three audiophile friends who, after hearing the Tact 2150 in my system, placed their amplifiers up for sale on AudioGon or Ebay, and purchased Tact amplifiers.

Tact 2150 Amplifier