The Balanced Audio Technology
Review by Dick Olsher
Low-level detail and dynamic nuances, the realm where the music's emotional drama resides, have also been a major hurdles for the acceptance of the format in high-end circles. Tubes have allowed the standard CD to close the gap, and more closely approach the potential of analog audio. The matrimony of tube technology and digital audio represents a holy union, blessed by the audio Gods. And from a practical standpoint, such a marriage gives the standard CD a new lease on life. It's gotta be da tubes!
The BAT people, Victor Khomenko and Steve Bednarski, have obviously seen the light, tube glow, that is. The original BAT CD player, the VK-D5, used six 6922 dual triodes to provide linear voltage gain, and a low-impedance output stage with excellent current drive. The Special Edition version, the subject of this review, substitutes the 6H30 "super tube" for the 6922. Because of the higher filament and bias current requirements of the 6H30, a beefier toroidal power transformer is also used. Another significant modification involves the introduction of the SIX-PAK output capacitor modules, which triples the value of the paper-in-oil signal capacitors. The enhanced signal drive of the new tubes can easily accommodate even low impedance loads via long interconnect cables.
The rest of the circuitry remains unchanged. As you might expect, the design is fully balanced in both the digital and analog domains. Four Burr-Brown PCM-63K DACs are arrayed in a true differential configuration. Complete differential signal processing is accomplished with just four circuit blocks A proprietary servo-board synchronizes the Phillips transport mechanism to a single master clock. The analog circuitry is distinguished for its avoidance of negative feedback, buffers, or op-amps in the signal path. And, oh, I almost forgot to mention that the player is HDCD compatible. Not a big issue for me, with only a measly three HDCD discs in my entire collection.
Let me give you fair warning: be sure to break-in the unit for at least a couple of days before you settle in for any critical listening. After this initial period, soundstage transparency and focus improve to mind-blowing proportions. So while not exactly a first impression, it was about this time that I realized I was in the company of an extraordinarily musical performer. It would have been patently ridiculous to compare the BAT's performance to similarly priced units. That would have been unfair to the competition. Thus, being a fair minded kind of guy, I decided to raise the bar and evaluate the BAT in absolute high-end terms, in the context of the best money can buy.
The Accuphase DP-90 transport and DC-91 processor have faithfully served me as a digital reference system for many years. Using multiple multi-bit (MMB) technology with 16 selected DACs connected in parallel, allows this system to significantly lower the digital noise floor and set the world record for low-level detail retrieval. No other player in my experience has had the knack of the Accuphase in this regard. And the BAT plainly fell short of this standard. Examined under a microscope, it was clear that its ability to follow musical nuances as they decay into the noise floor of the recording was not as clearly defined. Textural smoothness and detail resolution are at opposite ends of the spectrum. It's the eternal conflict between velvet and grain, silk versus sand. Every great player has to strike a dynamic balance between the two. Too much smoothness and detail is lost, and vice versa. The beauty of the Accuphase is that it's so easy to focus on a particular musical thread and follow its ebb and flow - without ever getting the impression that the presentation is overly etched or analytical. The information is all there, but it is so naturally and organically embedded in the fabric of the music, as to be totally believable. While the BAT packed plenty of detail, there was a threshold - relative to the Accuphase - below which nuances were lost. Its presentation was, however, always sufficiently relaxed, and it steered clear of etching treble transients, which is often confused for newfound detail by the neophyte. Designer Victor Khomenko has really nailed the sound of the analog output stage. It sings without the tube glare endemic to tube-based CD players.
It was in the areas of imaging and soundstaging that the BAT more than held its own. It was masterful in its ability to coax spatial information from a recording. Given an ambient recording, it was able to paint a remarkably spacious soundstage. The depth and width perspectives were, of course, influenced by the accompanying speaker and power amplifier, but when everything was right downstream, the BAT was as good as it ever got. Take a listen to Kevin Moore's self-named album, Keb'Mo' (Okeh/Epic EK-57863), voted 1995 country/acoustic blues album of the year. This is a lively studio recording (Red Zone in Burbank, California) that can absolutely come alive under the right circumstances. The BAT was able to paint a palpable and wonderfully focused image of the closely miked guitar and vocal. This was not an isolated instance. The BAT routinely excelled in clearly delineating instrumental outlines within the confines of the soundstage.
Midrange textures glowed with a slight tube warmth. Not at all a bad thing, and far more interesting musically than the sterile coldness of many solid-state CD players. Tonally, the BAT was well balanced from top to bottom. The upper bass and lower mids, the power range of the orchestra, were given proper weight. The mid and deep bass range was quite tuneful and packed the requisite punch. Overall, the BAT sounded well integrated with excellent speed and rhythmic drive.
About this point, I grew confident that the BAT could hold its own against any and all comers. Therefore, I decided to arrange for a final test. Mac, a local audiophile, had just put the finishing touches on an ultra high-end system. I'm talking Magnepan MG-20 loudspeakers, driven by humongous Krell amplifiers (model FPB 600c), lots of expensive MIT interconnects and cable, and at the front end - a Krell KPS-25sc playback system, which incorporates Krell's most sophisticated digital processor and transport. I'm talking about a Krell-designed "digital interpolation-filter system that is built around dual 80MHz Motorola DSP circuits to simulate higher sampling rates and provide more linear signal output to the digital-to-analog converter circuits," as well as "twin dual-converter DAC circuits that maximize processing power and eliminate common-mode distortions and data glitches." The cost of the front end is on the order of $20K, certainly a worthy competitor. So I arranged for a shootout, one cold wintry evening, or if you will, a battle of digital gladiators to the death. Mac, being a chef of some renown, had cooked up a delightful dinner. Finally, it was time for a glass of wine and good music.
After getting a sense of what the Krell system was all about, it was time to run the BAT CD player into the system, which we did through the analog inputs of the KPS-25sc. The sonic improvement was obvious and consistent with a variety of music. I was able to declare the BAT CD player the winner to my satisfaction. Mac is still in shock, and anxious to get his hands on a BAT for an extended audition. The differences, you ask? These I can describe in three words: depth, focus, and drama. With the Bat in the system, soundstage depth and image focus improved noticeably. In addition, much of the Krell's well-oiled sewing machine sterility was replaced by needed dynamic energy. The BAT simply allowed the music's emotional intensity to shine through more convincingly.
There are billions of CDs currently in circulation. I would suspect that the average audiophile's CD collection is in excess of 200 discs. Much of this music will never be available on SACD or DVD-Audio. I would also bet that despite all of the megabucks Sony and Philips are throwing at SACD, that most desirable music will continue to be released on CD for years to come. Hence, getting the most sound out of one's CD collection is a major audiophile concern that will continue unabated for years to come. What is perhaps not as clear is the optimum hardware strategy. In other words, does it still make sense to purchase an expensive CD player such as the BAT VK-5DSE ($5,500)? After all, the Sony SCD-1 SACD player retails for $5,000, and is compatible with standard CDs. Would it then make more sense to purchase the Sony instead and cover both bases? The answer, of course, would be yes if CD playback quality through the Sony were exceptional. Not to worry. Based on my listening impressions at the recent CES 2001, that is not the case. SACD sounded great, but CD was just OK. My advice is not to give up the search for a definitive CD player. The BAT VK-5DSE more than qualifies on that count. It is the perfect CD player with which to enjoy the music till the end of time.
Analog Outputs: XLR and RCA
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