BALANCED AUDIO VK-655SE
"The fully balanced purist-approach-based VK-655SE power amplifier is the ultimate expression of BAT amplifier engineering. It couples quickness, slam, and dynamic range with an extended, deep soundstage and an exquisite fidelity to the timbre and texture of instruments and voices... It’s time you experienced such beguiling sonics for yourself"
Purist approach. True dual-mono design
The fully balanced VK-655SE power amplifier is the ultimate expression of BAT amplifier engineering. Available in stereo or monoblock configuration, it features only two gain blocks in a high-power, zero feedback, and purely symmetrical design. A true dual-mono component featuring independent channel assemblies, power transformers, and separate power cords for the left and right channels, the purist-approach-based VK-65SE yields maximum soundstage width and depth. Finite micro- and macro-dynamics are reproduced with ease. A revised power supply incorporates second-generation oil-filled capacitors, dramatically lowering the noise floor and portraying grain-free, extra-refined harmonics.
Massive power :
Enough energy to lift most speakers off the ground
The VK-655SE’s elegant signal path follows BAT’s purist approach of using zero negative feedback to achieve the goals of wide bandwidth and circuit linearity. Its circuit is based entirely on N-Channel MOSFET devices. A high-current design that offers a robust 600 watts per channel into a four-ohm load, the VK-655SE easily drives most any speaker ever made. The monoblock version doubles these figures, and contains a whopping 1800 joules of energy storage—enough to lift most speakers over one meter off the ground! High power—combined with high-energy storage.
" The VK-655SE’s massive power rating (300 watts per channel into an 8-ohm load, or 600 watts into 4 ohms) enables it to support even the most power-hungry loudspeakers”
Jeff Dorgay, Robb Report
Sublime music reproduction : Speed, slam, dynamics
Dynamic responsiveness remains the recognizable difference between live and reproduced music. The VK-655SE couples quickness, slam, and dynamic range with an extended, deep soundstage and an exquisite fidelity to the timbre and texture of instruments and voices. Indeed, the sound of the VK-655SE and REX 3 power amplifiers converge upon the same ultimate goal: sublime reproduction of music independent of the devices employed. By utilizing only the highest-grade parts throughout, BAT allows the VK-655SE to yield supremely transparent insight into any music you play. It’s time you experienced such beguiling sonics for yourself.
Output per channel at 8Ω/4Ω
300W / 600W
Conversion to Mono ?
Output in Mono at 8Ω/4Ω
400W / 700W
3Hz to 250kHz
THD at full power
Input Impedance - stereo version
Input Impedance - mono version
Gain - nominal into 8 ohm
12V trigger Input & Output
Power Consumption idle-full power
400W / 2000W
19" x 9" x 23.5"
VK-655SE MONOBLOCK PAIR
What they say ...
"What the VK-655SE does deliver is musical accuracy, exquisite tonality and bass control. With 1,800 joules of power available, the VK-655SE controls the lower half of the frequency spectrum in a way that precious few amplifiers can muster at any price.
A Quick Comparison
If you believe all amplifiers have the same sound, stop reading now. Though the world’s top solid-state amplifiers are starting to sound more similar than disparate, differences in sonic character still exist. Side-by-side comparisons to a few of our regular amps reveal the BAT to excel in speed, dynamics and bass weight. The Burmester and Pass amplifiers in our stable are slightly warmer tonally, while the big Simaudio MOON 880M monos sound as natural as the BAT, but more bottomless in power capability—albeit at a higher price than a pair of VK-655SEs. It’s almost like comparing an Audi to a BMW or a Mercedes; all are excellent, though they go about delivering the goods in a slightly different way.
None of the speakers we have on hand present a challenging load to the mighty BAT. The current-hungry Magnepans and even our vintage Acoustat 2+2s, which have only an 82 dB sensitivity rating and are not much more than giant capacitors placed across the speaker terminals, do not diminish the amp’s performance in the least. Where some amplifiers can be speaker-dependent and struggle at times, the VK-655SE effortlessly powers every speaker we have on hand with ease.
Part of the neutral sound quality of the VK-655SE can be attributed to its use of all N-channel MOSFET output transistors. The N-channel MOSFET has a higher electron mobility, which makes amplifiers with them appear to have more transient speed than amps with mixed devices. Cursory research on the N-channel MOSFET implies that the N-channel device also has a wider range of operation where it acts like a triode tube—another great thing to have in a power amplifier. Techie bits aside, this amp succeeds brilliantly, especially for $17,500.
Bigger Is, Well, Bigger!
Some arguments in audiophile circles—about the quality of the first watt and that, because of their inherent complexity, higher-powered amplifiers are not as pure as low-power amplifiers in design and thus sound—don’t always hold true. Those arguments certainly don’t hold true in the case of this amplifier. While I’ve heard excellent examples of both low- and high-powered amps, I still tend to prefer the effortlessness of a high-powered one, even at low volumes. The VK-655SE takes a novel approach, featuring no negative feedback and only two gain stages in the entire circuit. In the same way that some large speakers manage to disappear in your listening room like a mini monitor, the VK-655SE has the sheer might of a large amplifier and the nuance of a small power amplifier.
Listening to acoustic instruments highlights the character of the VK-655SE. Its enormous power reserves might not be noticed with less-demanding fare, but the instant a drumstick hits a cymbal or the string of a standup bass is plucked with force, the boundless reserves of this amplifier deliver the dynamic swing required to convince your auditory system that perhaps you’re not listening to recorded music at all.
This is equally true when reproducing a vocalist with a wide range. Whether it’s your favorite opera or Prince, the VK-655SE’s instant delivery comes through free from the stress associated with lesser amplifiers unable to keep up—and this ability is too often overlooked when jumping on the low-power bandwagon. Simple as it might seem, a big, well-executed amplifier just sounds bigger and has a lack of restraint that further contributes to its overall neutral character.
There was nothing that the VK-655SE couldn’t handle effortlessly during this review. In the realm of the reference speakers at my disposal—all with sensitivity ratings of 87 to 90 dB—I can’t imagine ever needing more power than this amplifier delivers. BAT gear is known for its fantastic build quality and excellent secondary-market value, so for an amp at this size and price, I also can’t imagine ever needing another one once you’ve stepped up to the VK-655SE. Unless of course you need a second one"
What they say ...
SoundStage! - Australia
Peter Katsoolis December 1, 2019
Conclusion: Big Audio Dynamite
"To say that the flagship BAT VK-655SE power amplifier is just another high powered solid state amplifier from America is to say that Bob Dylan is just another song and dance man. Its outward appearance may be more utilitarian than many products these days but the serious engineering is where it matters, underneath the hood.
The design is ingenious. With its zero feedback, two gain block design, it owes as much to simple and pure low power designs as it does to scorched-earth, high power types. To say the BAT gives you a warm tube sound without the tubes is not telling the whole story of the core sound signature of this fantastic amplifier either.
Its performance was not at all what I expected and it soon left no doubt that I was in the presence of something very special indeed from an audiophile perspective. In the six months that it took up residence in our system, it performed without a hiccup. But for the power bill, I would have forgotten it was on. The VK-655SE is a fantastic all-rounder that played with a myriad of different components, both balanced and single ended, and drove a variety of speakers, all without a glitch. In every instance, the big BAT was intensely musical with ample soul to burn.
When it came to effortless dynamics, ultimate bad-ass low bass performance and rhythmic drive and grip from the basement to the treble, the self- effacing BAT VK-655SE was unsurpassed in my experience. It otherwise delivered in most every sonic parameter you could ever want or think of.
When you factor in the price, although not cheap, it represents massive value for money compared to many other “statement” pieces. And you can get it as a gleaming silver machine too. The BAT VK-655SE is big audio dynamite and is highly recommended."