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Equipment Review
August 2005

Conrad-Johnson ACT2 Preamplifier

by Tim Aucremann

"With the ACT2, Conrad-Johnson has again moved the bar that discriminates the state of the art."

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Aesthetics & Sound

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Review Summary
Sound "Best-of-breed dynamic range and spatial ambience, a vanishingly low noise floor, a sense of immediacy and life." "The music was coherent and focused without hint of the mechanical; it evinced an unpredictable yet ceaseless flow with ease and spontaneity." "The ACT2 is one of those rare watershed components whose fundamental strength lies in the overall coherency, naturalness, and balance it brings to musical reproduction."
Features Remote-controlled, single-ended-only line-stage preamp that uses "four Russian-made 6N30P triodes mounted to sockets on a suspended circuit board." "As successor to the ART, the ACT2 represents Conrad-Johnson’s latest thinking on the state of the art in two-channel audio reproduction." "Whereas the ART used five 6922s per channel (ten triode sections in composite), the ACT2 only needs two 6N30Ps (four sections) per channel to yield its 20.5dB of gain."
Use "In shipment, the internal suspension is fixed via screws, and these must be freed during setup." The ACT2 "consistently sounded best after its tubes were lit for an hour."
Value "Indeed, [the ACT2's] $13,500 USD price tag is lower than the ART’s. While that’s still a heap of money, it is refreshing to see reference-quality componentry actually come down in cost."

The "2" designator in the name of Conrad-Johnson's Advanced Composite Triode preamplifier denotes its direct lineage to Conrad-Johnson’s celebrated Anniversary Reference Triode preamp. The ART was produced in a limited edition of 250 to celebrate the company’s 20th anniversary in 1997. The $16,000 ART begot the Premier 16 and 17 line stages, and today its seminal topology is handed down yet again. As successor to the ART, the ACT2 represents Conrad-Johnson’s latest thinking on the state of the art in two-channel audio reproduction.

Former SoundStager Wes Phillips once remarked that the aesthetic design of the ART reminded him of Frank Lloyd Wright’s Falling Water. It probably is a stretch to think of the ACT2 as a retro-industrialized Guggenheim Museum, but it certainly is a visual departure from C-J’s previous designs. Perhaps the ACT2 more closely resembles a nouveau-Jetsonian prop in a science-fiction laboratory than it does a work of high architecture. There may be a hyperbolic hint of truth in such a description because, once alight, it can turn invisible at will. Before that happens, let’s take a closer look.

State of the ACT

The ACT2 is large for a line-stage preamplifier: 19" wide and 15 3/4" deep, the same footprint as the ART and Premier 16. Rising from its deck is a command console whose stylishly curved metal casing backdrops a clear, ring-shaped Lucite tube cage with vented acrylic top. Total height is 5 3/8". To the right of the tube ring is a control area with pushbuttons surrounding a porthole wherein relative numeric volume indicators light up in amber, one for each channel. These go from 0 to 99 in approximately 0.7dB increments and are easily read from across the room. Within the porthole, the name "ACT2" lights up in a red, vaguely oriental font above the volume readout. The front of both console and deck sport 1/4"-thick champagne-colored faceplates.

Inside what I dubbed the "Tuburgring" (after Nurburgring, another famous circuit) sit four Russian-made 6N30P triodes mounted to sockets on a suspended circuit board. In shipment, the internal suspension is fixed via screws, and these must be freed during setup. High-temperature silicone damper rings are supplied, two per tube. The 6N30P (or 6H30Pi if you parse Cyrillic) is a Russian military tube that made its C-J debut as a pair of phase inverters in the Premier 140 amplifier. It is a long-life tube; expect 10,000 hours from it.

Conrad-Johnson’s adoption of the 6N30P for use in the ACT2 appears to signal the company's long-term acceptance of this tube as a replacement for the 6922. The 6N30P is a high-current/low-voltage device whose very low plate resistance requires no cathode follower. It makes for a nearly ideal preamp tube. Whereas the ART used five 6922s per channel (ten triode sections in composite), the ACT2 only needs two 6N30Ps (four sections) per channel to yield its 20.5dB of gain. Indeed, Lew Johnson commented to me, "The 6N30P has some unique advantages -- mainly exceptionally high transconductance, allowing it to substitute for three to four of the 6922s. However, it has commensurately high current demands on main B+ and heater supplies, so costs are roughly comparable to a unit using three to four 6922s for each 6N30P." Expect to see this tube showing up in another new preamplifier from Conrad-Johnson using trickle-down technology from the ACT2.

The elegant composite triode circuit that Conrad-Johnson used in the ART, and now in the ACT2, has been described frequently in the literature, so I won’t repeat what you can read on the Conrad-Johnson website and elsewhere. Like the ART, output impedance is just under 500 ohms. Audio and control circuits each have their own power supplies, and, according to C-J, the ACT2 makes generous use of polypropylene, polystyrene and Teflon capacitors in both. Where the ART required two chassis to house its five tubes per channel, the ACT2 fits itself within a single box -- no doubt shaving costs and keeping signal paths short. Indeed, its $13,500 USD price tag is lower than the ART’s. While that’s still a heap of money, it is refreshing to see reference-quality componentry actually come down in cost.

On the backside of the ACT2 are plenty of inputs and a pair of main outputs. All are gold-plated OFC single-ended RCA jacks. There are five line-level inputs along with two pairs of inputs and outputs that offer unity-gain support for an external signal processor, or for routing two-channel output to a surround-sound processor. If your amplifier supports it, a 12V terminal volunteers trigger output so you can turn an amp on and off from the ACT2. A sturdy IEC connector mates to a 10' 16-gauge power cord with hospital-grade plug; it looks just like the one supplied with Conrad-Johnson's Premier 140 amplifier.

Operationally the ACT2 is a piece of cake. Documentation is concise and complete. A hex-head screwdriver is included for removing the tube cover. A hefty metal remote manages input selection, volume, mute, and channel balance (the latter is not available from the console). A button on the front panel controls standby mode, in which all tube circuits are switched off. Standby can also be controlled by holding down the mute button on the remote for more than three seconds.

Review context

In an apparent fit of beneficence, our dear editor has allowed my system to remain unchanged for a few months. For purposes of this review, vinyl playback issued from a cocobolo Teres 255 turntable mounting an SME V tonearm with a Shelter 901 phono cartridge. From there, signal wended its way through FMS Blue II phono cables to a Pass Labs Xono phono stage. From the Xono via FMS Zero interconnects to a Conrad-Johnson Premier 16LS line stage, current was passed to the impressive Conrad-Johnson Premier 140 amplifier or the tonally scrumptious Thor Audio TPA-30 Mk II monoblocks.

The amplifiers powered Audio Physic Avanti Century loudspeakers via Shunyata Lyra cabling. A variety of brass cones and maple blocks supported most electronics. A Parasound 2000 CD player mounted on Symposium Rollerblocks fed the preamp using Shunyata Aries interconnects. AC to everything came through an original Shunyata Hydra power conditioner. The ACT2, likewise plugged into the Hydra, sat on Lloyd Walker brass cones pointed into a maple board. It consistently sounded best after its tubes were lit for an hour.

The Premier 16LS is served well by tube rolling its stock Sovtek 6922s, and for much of the review period mine ran six quiet and well-matched Amperex 6DJ8s. In the ACT2, I experimented with four 6H30Pi-R NOS tubes (early '80s Russian military) versus the 6H30Pi-EBs that come out of the box. I can’t say I heard much difference between these tubes.

Frankly, I was a tad equivocal about inserting a component that is double the cost of most other pieces in my system. I feared the ACT2 might expose gross deficiencies from its upstream or downstream neighbors. But like the good friend who makes you feel you’re a better person when he’s around, the ACT2 appeared to reinforce rather than critique whatever virtues my system has.

The sound of music

There I was in full reviewer mode, all set to scribble notebooks full with initial impressions. The gear had been switched on before dinner; a fresh pad of paper lay at the ready. The house was wholly quiet as I dropped the tonearm and scooted back to my seat. Hours later, I’d written one run-on sentence. It read: "Oh my goodness, this is so natural, so analog -- everything is better." Not exactly haut reviewer-speak, but you get the idea. I liked what I heard. Hearing the ACT2 in my system for the first time, and each day since, has opened my ears to new levels of two-channel enjoyment and musical appreciation. Months later, that initial comment still captures the kernel of my listening analysis.

In a nutshell, the ACT2 is one of those rare watershed components whose fundamental strength lies in the overall coherency, naturalness, and balance it brings to musical reproduction, while itself residing in a vacuum of flaws. In audiophile terms, all the sonic goodies fall easily to hand: best-of-breed dynamic range and spatial ambience, a vanishingly low noise floor, a sense of immediacy and life. Yet, when I go back to read my listening notes, I find them describing not a device with a sonic signature, but the music I was hearing when I wrote them.

Reviewing the ACT2 poses a dilemma. How does one give an account of a preamp that apparently adds precious little to the signal fed to it? If it can be said to have "a sound," the sound of the ACT2 is the sound of the recording, the sound of music.

One of my favorite albums for reviewing is the Lyrita recording of Gerald Finzi’s Intimations of Immortality [Lyrita SRCS 75]. A musical interpretation of a Wordsworth poem by the same name, this is a work for orchestra, chorus and solo tenor that offers a full-range workout for any piece of audio equipment. The composition opens slowly with a solo horn, followed quietly by the first and second violins, then on to violas, cellos and basses that indulge a major theme, gradually building in crescendo to brass and cymbals, then dying away to the plaintive voice of a clarinet. I thought I knew the music well; yet listening through the ACT2 elucidated previously unheard textures of conductorial nuance and musical expression. It took me some time to account for the differences I heard, all the while enjoying them in ignorance. My notes for this recording and others are littered with comments to the effect that "there is something different at work here, something about the dynamics and timing of the music that brings new meaning to it."

Static characteristics such as 3-D imaging and interstitial blackness may be touchstones of high-end stereo reproduction, but I rarely think of them when listening to music, live or recorded. Every sonic event has duration and amplitude. At the heart of musical expression lie dynamics and timing, the cause of our perception of music as vivacious and flowing, always moving forward. The more a component is right with these changes, the more revealing it becomes relative to the original performance.

Composers litter their scores with notational marks governing timing, expression, intensity and volume. Indeed, movements in classical compositions are named after their tempi. A conductor uses these notations to guide musicians in expression of his interpretation of the composer’s intent. Variations in dynamic emphasis and pace account for different interpretations and differentiate great performances from others. The same music -- the same notes -- played by the same orchestra under different conductors (different "master clocks") will indeed sound different.

As Vernon Handley took the Guildford Philharmonic Choir & Orchestra through the opening bars of Intimations, the ACT2 revealed a continuity of dynamic shading, temporal phrasing, and natural decay I’d never heard before. I did not have an experience of hearing fine details, although they were there for the having. The ACT2 did not parade before my listening seat saying, "See -- I dug this nugget out of the groove for you." Instead, the music was coherent and focused without hint of the mechanical; it evinced an unpredictable yet ceaseless flow with ease and spontaneity. Low-volume passages slowly metered displayed a previously unheard drive and energy as the ACT2 laid bare, in a handful of opening measures, anticipation for what was about to unfold. On the microscopic level of a few notes, the effect is small. Across an aggregation of musicians into sections and sections into an orchestra, and across the measures of a score in time, the cumulative effect took me steps closer to the natural vibrancy -- the reality -- of music. The cause may have been Teflon caps and shorter signal paths, but the effect was sheer delight.

Timing is concerned with the proper placement of beats, and some beats are emphasized more than others. Such emphasis is frequently dynamic -- cashed out as a brief and often subtle variation in loudness or intensity. Different emphases yield different interpretive results. Timing also describes the moment of arrival and departure of notes or "sonic events." The speed at which these events arrive tells the tempo at which the conductor is driving the orchestra. The coupling of individual sonic events creates flow and rhythm.

Why do elements of musical structure merit discussion in an audio review? Simple: It is the intimate partnership of dynamics with timing and rhythm that brings sounds to life as music. Herein lies the core, I am convinced, of how the ACT2 lets music be itself and why it sounds so right. It asymptotically approaches the sound of live music because it conveys a truer-to-life synthesis of dynamic and temporal phrasing across the entirety of its broad frequency range.

Just as a conductor controls the energy of the instruments under his baton, the ACT2 manages the release of electrical energy across time in a way that is as veracious as the recording at hand, and never more so. If a section of violins enters a bar a quarter-second early you hear a fine-spun bloom; if one of two drummers playing the same part does this, you hear an annoying echo. The inability of a lesser component to capture such nuance might be characterized as a kind of temporal distortion, as if the smallest unit of time available to it is not small enough to differentiate all the aural information passing through its circuit. However, I do not perceive the ACT2 delivering control as an additive attribute; it allows music to speak for itself unfettered by electronic pixelation, or temporal jitter. Analytically, I hear a refusal to smear or blur leading and trailing edges of complex waveforms regardless of their dynamic. Synthetically, I grasp the vicissitudes of musical creation, the product of real performers in time and space.

Listen to the delicate phrasing in "Scene at the Brook" in Beethoven’s Pastoral Symphony conducted by Andre Cluytens [EMI ASD 433] as the flute, clarinet, and oboe warble their bird-like cadenzas andante molto mosso -- at a walking pace and very animated. Each instrument is clear and distinct. The temporal and dynamic hues of expression, the marrow of the musician’s art, come simply to the listener as beauty and serenity. There is no sense of a device mapping signals to its own internal gradient -- the ACT2 renders this music in a way that is continuous, that is quintessentially analog. Try any enjoyable passage of acoustic music, with multiple performers playing quietly, to hear how this preamp gets out of the way of modulation and meaning. I struggle in my description -- how does one describe music?

Couple a deft handling of timing and dynamics with the ACT2’s natural (there’s that word again) clarity and focus, and the result is immediacy with an "oh my!" kicker. Under the ACT2's sway, the chorus in Intimations became a living, breathing collection of individuals standing together. Chests swell with air as their song is beautifully inflected. Listen, for example, to the phrase "Waters on a starry night are beautiful and fair," as a host of soprano tongues hit the roofs of their mouths on the final "t" in "night" and as the singers intake breath after. The performers are palpable and their images unwavering. People and instruments have weight and dimensionality. One has the sense -- to pinch a phrase -- of being in the "living presence" of the musicians themselves.

On "That’s the Way She Loves" sung by Aaron Neville (Warm Your Heart [Classic Records/A&M Records RTH 5354]), hear -- and in your mind’s eye, see -- the solidity of the insouciant saxophone hanging mid-air in its own reverberant pocket of pitch-black background. Every dynamically modulated whack and donk of the cowbell in Hugh Masekela’s "Stimela" comes across with the rich dimensional harmonics of a stick hitting a hollow metal bell (Hope [Triloka TR 8023-2]). Minute sonic artifacts are there in spades, but I did not hear them as etched, pingy details. Phenomenologically, details are there for your focus, yet the ear is not drawn to them without conscious effort -- they simply occur within the whole, contributing to the immediacy and vitality of each performance.

An accurate portrayal of massed strings is a challenge for most audio components. Too often a section of 16 violinists all playing the same note comes across as a handful of performers playing louder. Listen to how the ACT2 unfolds the quiet passages in the first movement of Sibelius’s Symphony No. 2 [Chesky Records CR3]. If you want to hear the expressive use of tempo and dynamics that Barbirolli draws from his orchestra, listen to the violins and most particularly the violas and cellos in this piece. Even in supporting roles, I heard masses of strings present a shimmering intensity of sound, Aeolian in movement, rife with the resonance that comes only from multiple bows in the hands of talented musicians.

The ACT2 is so even tempered, so at ease and natural in its delivery, that no single characteristic stands out beyond what the music itself delivers. My earliest impressions held true throughout my time with this preamp -- everything is better. The absence of any particular sonic emphasis becomes more conspicuous than its presence. When a recording was good, it was very, very good, and when it was bad, well, I knew it.

With all the right stuff in near-perfect balance, if there is a Golden Mean award for preamps, the ACT2 gets my vote.

A difference of relatives

It has been said that the Conrad-Johnson Premier 16LS line stage ($7995) offers 80% of the sound of the ART in a single-chassis design. Nonetheless, at almost half the price of the ACT2, you might be undecided by a comparison of the Premier 16LS to its pricier relative. But there are times (and this is one of them) when the law of diminishing returns does not apply. After all, when Dr. Frankenstein built his monster, the lightning bolt may have been only 20% of his "ingredients," but where would things have gone without it? In a backhanded way, a comparison of the '16LS and the ACT2, suggests that: (1) the '16LS truly is a top-flight preamp that deserves its place in the C-J pantheon of Premiers, and (2) magic is expensive.

I remember a dealer advising me that if I liked the tubey lushness of my Conrad-Johnson PV-8, I probably would not like the leaner Premier 16LS. While the character -- if it can be said to have one -- of the ACT2 is more neutral than that of the '16LS, it is clear that both preamps come from the house of C-J. The ACT2 represents a big step up on the focus, speed, and transparency of the ART’s younger brother without casting aside familial harmonic resemblances.

Listening to Loren Maazel take the Cleveland Symphony through Tchaikovsky’s Symphony No. 4 [Telarc 100047], I heard the ACT2 offer a greater clarity of layered depth to the soundstage. Depending upon recording, the ACT2’s soundstage stretched beyond the '16LS’s, sometimes by several feet outside the speakers. With the newer preamp, instruments resided more firmly in focus, whereas it was surprising to hear the Premier 16LS sound warmer and looser in all dimensions.

Even at lower volumes, the ACT2 delivers gobs of musical information. In pp passages that are light or airy, high notes have their own sense of harmonic weight. So often I found myself leaning forward -- not to hear better, but in rapt attention to artistry revealed. What editorializing there was came from the recording engineers or the medium. Here, the two components parted company -- the ACT2 passing along that differential spark, that extant magical whatever that hints at the limbic level that live music is afoot.

Definition and clarity in the lower registers are (at least in my system) two of the strengths of the Premier 16LS. Here the familial resemblance continues evolved. The ACT2’s rendering of low bass is superb, stunning if I may be so demonstrative. I heard no overemphasis in the midbass because of low-end roll-off. The dynamic range of the ACT2 is immense. The attack of the trombones in the Tchaikovsky Symphony’s fourth movement come through with a punch and solidity that, for as good as the '16LS is in these areas, are beyond that preamp's weight class. High notes from violins and trumpets are natural -- sweet or crisp, but never saccharine or edgy. In the pizzicato third movement, plucked strings were fast, articulated and harmonically rich.

For comparatives pertinent to earlier comments on dynamics and timing, listen to the piccolo solo in the third movement. The piccolo is the highest pitched of all orchestral instruments and easily capable of cutting through an orchestra going full bore. This solo is one of the most difficult in all of piccolodom -- only 21 notes, but they require delivery in a scant three seconds. Prior to the ACT2, I thought the Premier 16LS delivered this part with clarity and élan. In comparison, it is easy to hear the finesse the ACT2 brings. While the Premier 16LS permits all the notes across the finish line, their leading and trailing edges bump into one another -- notes sound smeared compared with the precision and clarity with which the ACT2 renders each. Through the Premier 16LS, the flutist’s attack on each comes across as forward and a wee bit metallic. It cuts through the orchestra, but with a hint of stridency, each note undifferentiated with respect to dynamics and speed. By contrast, the ACT2 reveals the artistry at work in the playing as the solo rises above, its high notes sounding alive, inflected, and natural without overemphasis on their leading edges.

Please keep in mind that these contrasts are strictly relative. The Premier 16LS has been my reference for several years, and in prior commentary I’ve dubbed it "a preamp with soul." If you know it well, be at ease knowing it presages the ACT2.

ACT finale

Confession time: not long after placing the ACT2 into my system the stock-in-trade audiophile words went willingly to bed, left-brain attribute-parsing begged shutdown, and the sheer joy of listening secured ascendancy. Throughout my time with it, the ACT2 let recordings offer what they have and consistently drew my attention to the music and away from thoughts and sounds of componentry. In effect, once it arrived, it promptly disappeared.

So, at the end, and at the risk of sounding mawkish, I’ll state that the ACT2 is the singular most complete component to grace my system to date. I have no higher compliment to give. But there is a small flaw -- well, more of a disappointment -- that I kept experiencing over and over: Each time when I opened my eyes, the musicians weren’t really there.

Just when you think your system has reached a plateau, it is reassuring to know that talented designers and manufacturers continue to push the envelope of satisfying two-channel reproduction. With the ACT2, Conrad-Johnson has again moved the bar that discriminates the state of the art -- not an easy feat considering where they already set it. If you love music and this crazy hobby, go listen to the ACT2. Play good music through it and you'll find plenty to discover.

...Tim Aucremann

Conrad-Johnson ACT2 Preamplifier
$13,500 USD.
Three years parts and labor.

Conrad-Johnson Design, Inc.
2733 Merrilee Drive
Fairfax, VA 22031
Phone: (703) 698-8581
Fax: (703) 560-5360

E-mail: service@conradjohnson.com
Website: www.conradjohnson.com

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