April 2000Balanced Audio Technology VK-40 Preamp
by Jon Gale
Detroit, 2017 AD: SoundStage! reviewer Jon Gale prepares to audition the latest plug-in algorithm for the Synaptic SMD-3 (Synaptic Molecular Displacer) transducer under test. After uploading room/listening bias data to the Synaptic central database, his personal code is downloaded into his CHC (Central House Controller). Scrolling through his personal music profile, he selects the new all-acoustic blues set from ZZ Top, still sampling after all these years .
Sound far-fetched? Hardly. Here's the deal. In 2010 or so, we will finally have in place a high-definition encoding standard for all major media, be it music, film, or print. (Yes, print. This will be in an "electronic paper" with programmable ink. Believe it.) By 2017, our transducers (speakers) will house the source controls, amplification, crossovers, and final wave launch -- all controlled from the listening position via remote.
Alas, that is then, this is now. In the interim, what we need is a relatively affordable system controller (preamp) that passes as much of the signal as possible with minimal damage. Well, follow me fellow cyberphiles; I've found just such a unit.
Up to BAT
One of the few recent success stories in our industry is the Balanced Audio Technology saga. BAT was seemingly launched fully developed, with a product line voiced to stomp the tundra. Count me smitten, as I purchased the VK-3i tubed preamp a few years ago. It was in learning of the new solid-state VK-40, priced above the VK-3i, that my interest was piqued. This review afforded the rare opportunity to compare a piece to one further up the product line, and with a different topology at that. I was very interested in not only whether BAT could retain the magic in a solid-state preamp, but also if they could retain the high value at an increased price point.
The BAT VK-40 will gracefully adorn any equipment rack, measuring a largish 19"W x 14.5"D x 6"H. Wearing refined cosmetics, the minimalist front panel gives little clue to its control-center flexibility. This solid-state, fully balanced design boasts of BATs purist approach to topology. According to the manual, the VK-40 uses zero feedback for wide bandwidth and linearity, and it features a "symmetrical N-channel Unistage gain block" biased at 250ma for high current delivery. The dual-mono design harnesses over 130,000uF of power-supply capacitance while incorporating a shunt volume control with Vishay bulk metal-foil resistors in the signal path (140 steps in .5dB increments). Add to this a customizable user interface for input/program control. Via front panel and remote, any of the five signal inputs can be programmed with a number of parameters, including balance, relative volume offset (any input with respect to any other input), phase, mono/stereo, maximum volume setting for any input, and fixed volume setting for any input. The review sample was supplied with the optional machined aluminum remote; a plug-in phono module and SIX PACK output-capacitor upgrade are available as options. The VK-40 also has two signal outputs for bi-amping or different listen "zones"; the inputs consist of three XLR and two RCA, along with one RCA tape out.
Associated equipment for this review was the following. Front end consists of an Enlightened Audio Designs T-1000 transport feeding a Camelot Dragon Pro-2 Mk I for jitter reduction and resolution enhancement. A Theta DS Pro Gen. III DAC fed the VK-40 via MIT-330 Balanced Terminator interconnects. The Bryston 4B-ST amplifier was used in its balanced mode to drive a pair of Vandersteen 3A Signature loudspeakers. Cables are generally MIT system-wide (MI-330 Proline Terminator Balanced interconnects, Digital Reference digital cable, MH-330 Balanced Terminator speaker cables, MH-750 BI-Wire speaker cables, MH-750 Plus interconnects, Z Cord II power cord) along with Kimber KCAG interconnects, Altis Ultimate AT&T digital cable and van den Hul The First interconnects. Acoustic treatment consists of an assortment of ASC Tube Traps and Flat Traps.
Use and listening
Setting up the VK-40 was a straightforward affair, made this way by its relative immunity to tweaks. No wholesale changes in sound were found when replacing power cord or mounting feet, which bespeaks of proper power and chassis engineering to begin with. I finally settled on mounting the VK-40 on three Black Diamond Racing carbon-fiber cones housed in a Michael Green Design Just-a-Rack. The user programmability of the VK-40 is a very nice, if superfluous, touch. For example, you can name any input whatever you want, if you would want to do this. One very useful touch is the ability to program each input with its own gain setting, thus eliminating any differences of output gain for each separate source.
During the VK-40's stay, my system context was altered by the removal of my subwoofers, as I did not have the required balanced crossover modules for the Vandersteen 2W-Qs. (The VK-40 offers balanced outputs only. Adapters are available for single-ended connections.) This change, as you will read, was a very large factor in the outcome of this review. I gave the VK-40 a few days break-in, and a few more followed so as to acclimate to the system sans subs. In hindsight, I neednt have bothered. What was immediately evident was an absolutely rock-solid bass presentation well up into the midrange. Im not referring to the proverbial "well delineated" or "tight" reviewer appellation. This was a wholesale increase in definition and solidity over the VK-3i. Yes, it was ripe and full, while also extremely controlled and nuanced -- a neat trick.
The sonic payoff with this performance is a sense of solidity in imaging that I have rarely experienced. Im not referring to image outlines, although this area is helped greatly, but in the sense of instruments being anchored to the stage. Pianos were huge, heavy instruments sitting on large hollow-cavity stages; basses and cellos were firmly spiked to a wooden floor. The list goes on. The increased performance in the portrayal of hall/ studio reverberation takes imaging to the next level. It is in this low-level/low-frequency signal that many of our directional clues, and certainly a hall's volume, are revealed. One fact should be made clear: Whether it is acoustical or electrical, getting the bass right helps everything above it. Ridding the signal/room of bass smearing and overhang unmasks delicate information in the upper octaves. For the duration of the VK-40s stay, only on the rare piece of music did I miss the subwoofers. The review sample did include the optional SIX PACK output-capacitor upgrade. As to how much performance increase is obtained over the stock unit I cannot say. I will say that given the performance obtained with this sample, I would treat the SIX PACK as a necessity.
Concerning overall tonal balance, you can hear where certain compromises were made in this unit -- the proverbial "sins of omission" vs. "sins of commission." The heart of the midrange had the same full-bodied, anchored-to-the-floor depiction as the bass. What was mercifully absent was any etch or hardness in the upper midrange/lower treble. This "weight" of presentation was a wonderful help to commercial multi-miked classical fare. Using the violin section as an example, close multi-miking exaggerates the upper harmonics of the strings from the halls reverberation, further adding to the dreaded string "glare." While the VK-40 does not homogenize this effect, it fills in with its solidity of presentation, the "body" of the string section. For those of us who do not adhere to audiophile-label, naturally recorded fare, this is a great help in the playback of commercial classical discs.
Conversely, there is a slight opacity, or loss of resolution, in the upper octaves that slightly shortens soundstage depth and the sense of hearing back to the corners of the hall. While the treble is very well rendered and extended, blending superbly with the midrange, I just didnt seem to hear quite as much hall sound or low-level information. Lateral imaging was very good, being able to seemingly spread the speaker radiation pattern (not image outlines) to room-filling capacity at times, thus helping a speaker sonically disappear as sources of sound. Vocals, particularly male, were very well served by this "solid" depiction. Midway through the review period, a professional recordist and friend brought over a DAT master of a male choir he had recorded the week prior. While the presentation was certainly "of a whole," I was struck by the fact that I could distinctly hear every individual voice. (It helps also that he does wonderful work, purist and minimally miked.) I must note that the preceding comments, especially concerning resolution, are made from a view from above. To obtain more performance will most assuredly require a much larger investment.
What struck me most with the VK-40 was its top-to-bottom coherency, hard enough to achieve at any price point, more so at this. There are many preamps that claim near-state-of-the-art performance in one specific area. The problem arises in that you constantly hear it. It stands in relief from the musical tapestry, thus turning the listener away from absorbing the musical meaning to concentrating on it. Not so with the VK-40. Although it indeed does have a strong point in its bass presentation, this strength actually assists the frequencies above, as if it pulls together the presentation rather than distancing itself in proclamation of a "strength." Many times you find a component that seems to suit one particular type of music over another. This component may suit your particular system, and it may suit your taste in music. It may even suit all your little shaded dogs in your collection. In the end, no matter what material I threw at the VK-40, from lightning-fast transients of bluegrass to the sustained swells of a full orchestra, it accomplished its task with a sense of ease, grace, and authority. It was like a velvet touch from an iron fist.
In comparison to the VK-3i
In a literally side-by-side comparison with my BAT-VK3i, the VK-40 really wasnt challenged. In bass definition, impact and solidity, the VK-40 soared. The increased articulation in this region alone will be worth the ticket price for many. Surprisingly, in the midrange, where I assumed the VK-3i would give a good fight, the final tally was for the VK-40. With its solid articulation extending well into the upper midrange, the VK-40 consistently imaged deeper and wider and was much more firmly centered. Tonal voicing in this area was, in a word, truthful. Ive heard many pieces of BAT gear, and there's one thing for sure: these BAT guys never screw up the midrange. The treble is where I would give the VK-3i a slight edge. While the VK-3i seemed overall to be a touch brighter than the VK-40, it also seemed to breath a little more easily. The VK-40 had a touch of dryness, not to the point of being overly dark, that slowly recedes into the upper midrange.
BAT has done it again
Subtitled "Are these guys ever going to screw up?"
A preamp at the $4k price point still faces undeniable trade-offs in its design. As a reviewer, I have taken on the job of picking things apart. The VK-40 is the first product I have faced that, in listing its deviations from neutrality, every one of the design choices made seem musically consonant. The cost: benefit ratio line is drawn right here. To have this level of performance in a solid-state preamp offered at this price point is a major balancing act indeed. The BAT VK-40 has one of the most well-rounded presentations I've heard. I truly hated boxing it up.
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