KR Audio VA340
Integrated Amplifier
A Tale of Two Tubes
Review By Rick Becker
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  KR amplifiers are about as rare as Ferraris with South Dakota license plates. Their audio tubes, however, have reached legendary status. Regular readers of Enjoy the Music.com are well aware.  In fact, Senior Editor Dick Olsher just gave their new 300B Balloon Triode tube a Blue Note Award for 2005. Obviously, this is not a company that is standing still. In fact KR is the only manufacturer to develop new audio tube types since the mid-1900s. In addition to the two new tubes reviewed here, they have also developed the huge KR T-1610 which is now available in SET monoblock amplifiers putting out 100 watts per channel, and the KR T-100 which is good for 20 to26 watts.  At several Montreal and New York shows over the years, I've had great pleasure listening to various KR tubes in amplifiers from Art Audio, Balanced Audio Technology, Joule Electa and Nagra. For those just coming on board with this hobby, this is a very elite group of manufacturers, but do not be scared off so easily. There is something to be shared here for newcomers and old timers as well. (Editor's Note: In our Review Magazine Archives you will find reviews of an earlier version of the KR Antares VA320 power amplifier and the KR Kronzilla DM dual monoblocks).

The Beginning
I'm not sure how the story first began but I suspect I received a "Thank You" from KR in the Czech Republic in response to a favorable comment about KR tubes in one of my Montreal or New York show reports.  Eunice Kron, wife of the late Dr. Riccardo Kron who founded the company, is now the guiding light of KR Audio and in our correspondence over the past couple of years she has eloquently championed the continuing artisanship and development of the company. As coincidence would have it, one of her childhood friends lives near me in Rochester, and this, perhaps, seeded our friendship and the inevitability that I would one day have an opportunity to review a KR amplifier. That my wife, Linda, traveled to Eastern Europe twice during this time on mission work with her church further piqued my interest in this small company. Live music in the streets is not uncommon in Europe.

Great art is often created in humble surroundings. While I didn't expect the hand made KR vacuum tubes to be manufactured on the scale of a Coca Cola bottling plant, I asked Eunice to share some photos of her factory, thinking you, too, might be interested.  Women do the small microscopic mechanical construction that fits inside the tube, while men do the macro construction. Here are a couple of photos to give you a sense of the laboratories in which they work.

This operation is a far cry from the pristine new industrialism emerging in China in such industries as furniture, motorcycles and consumer electronics. But have you ever held a KR tube in your hand? When tube gear is seen on a shelf or on a stand the audio tubes tend to be dominated by the architecture of the entire amplifier. (Nagra's amplifier with the KR 845 would certainly be an exception).  And when the amplifier is powered up and the tube is ablaze, it is often more difficult to appreciate the miniature architecture inside the glass bulb. Blinded by the light? I think not, though I have often knelt down for closer examination of products at floor level. Holding a KR tube in your hand, however, you cannot help but notice the quality of the product and appreciate the artisanship of the craftsmen and women that build them. But it is also the invisible, such as the hard Simax glass and the high vacuum within that differentiates KR tubes from other brands. It takes passion for your workto build a tradition that achieves this level of manufacturing. Although KR Audio Electronics is a young company, its rise has been meteoric when measured by its accomplishment, rather than by its market penetration. The question then becomes, "Does world class construction translate into world class music reproduction?"

The Plot
I suppose you could call me a "Tube Guy," but I'm not a tube expert. To be honest, I don't know one electron from another. So if you were expecting a detailed explanation of plate voltages and cathode followers, you will probably wish Dick Olsher had reviewed this amplifier. If you want to hear about enjoying the music, keep reading.

A window of opportunity opened up this summer. Bill Martinelli, who builds very high quality horn loudspeakers on custom order here in Rochester, would be delivering a pair to Alfred Kayser, one of KR Audio's premier dealers in North America.  Would I like Mr. Martinelli to bring a KR VA340 integrated amplifier back to Rochester for me to listen to? I actually had to do some homework to answer that question. I've heard lots of high-end systems with 300B tubes that needed super-high efficiency loudspeakers to achieve a semblance of dynamic range. And at 6000 cubic feet, my listening room is toward the "large" side of the spectrum. But given that my Manley Mahis at 20 watts per channel in triode mode drive my tube-friendly Kharma 2.2 loudspeakers in my reference system, it looked like a possibility. The VA340 puts out 20 watts per channel in single-ended triode mode with either the 300BXLS tubes ($525 per matched pair) or the 842 HVD tubes ($525 per matched pair). Nonetheless, I offered that I would simply return the amplifier if it was not a good working match with my loudspeakers and large room. After all, fair is fair. Reasonable care must always be taken to match low powered tube amplifiers with appropriate loudspeakers for any given room size. Fortunately, today there are a fair number of outstanding loudspeakers that can meet the criteria, assuming the room size and playback volume are relatively moderate.

On a warm summer night, the crated KR amplifier ended up in the back of my Tracker, freshly smuggled in from Canada. It was an easy lift for two of us to load, but a minor engineering feat for me to unload it and set it up by myself. We're talking 80 lbs, plus the wooden crate. (I tip the scales at 162 lbs., not much more than the weight class I wrestled in high school). I placed the KR on a Stillpoints Component Stand which not only blended very nicely with the architecture of the amplifier, but contributed to the sound quality as well. For size comparison, a Mahi monoblock sitting next to the VA340 looks like a Mini Cooper parked next to a Hummer. This was going to be interesting. I was hoping the amplifier would come in time for me to try it with the excellent Escalante Design Pinyon loudspeakers that I had just finished reviewing, but no such luck. They missed by three days.

After using the amplifier during part of the review process for the Stereovox Studio hdse interconnect and speaker cable, I continued with the hdse interconnect between the DAC and the KR.  I was quite impressed with the transparency and focus of this cable as I mentioned in my recent review and I thought it gave the 300BXLS tubes a slight edge over my reference interconnects. For speaker cables, I reverted to my reference JPS Labs Superconductor+ that delivers a very solid bass to the Kharmas. Coming from Europe, the KR has the mandatory plastic shrouded speaker cable terminals that take all the fun and danger out of the sport, not to mention being awkward to use. They do guarantee that you will not over-tighten the binding posts, but on at least one occasion a post loosened up to the point where I lost the connection. I couldn't help but think back to the excellent proprietary binding posts on the Escalante Design loudspeakers.

On the back right side of the KR is the main power switch, right next to the power cord connection. Under normal use, it is left on all the time as the amplifier dwells in a kind of low power "sleep" mode. To fire it up completely, it is necessary to push a little button on the right front face of the chassis or alternatively, hit the orange power button on the small plastic remote control. A red led on the face of the amplifier comes on, which turns green in 8 to 10 seconds, and the music will jump to life if a source is already playing. This is the first high-end piece of equipment that I have reviewed that has a remote and I have to admit that it is instantly addictive. In addition to the power button, it has input selection and volume control.

Adjusting the volume seemed to require hitting the volume button twice for some reason — a minor annoyance that quickly became part of the landscape. Very small adjustments in volume were also difficult to achieve with the remote. I would have to go way over or under the desired volume and approach it from a more distant level, rather than try and make a minor adjustment. But I guess this is not uncommon. In flipping through the inputs, the different output levels of my sources resulted in being blasted by music when I passed by the tuner, which has a 2 volt output, unlike my muse DAC, which has a one volt output level. More judicious arrangement of sources would have prevented this, however. Overall, while I appreciated the light weight and small size of the remote control, it wasn't in the same manufacturing league as the amplifier itself. Perhaps it would be unfair to compare it with the wide variety of ergonomic designs available in computer mice, given the disparity of volume production, but the thought crossed my mind. Nonetheless, I used the remote almost exclusively during the review process without any serious issues.

The VA340 integrated amplifier is basically a combination of the Antares VA320 stereo amplifier and the P150 solid-state preamplifier. The architecture has been re-worked to allow the longer dimension to face the listener. This results in a more interesting layout of the various towers and a spacious, uncluttered layout of the various front controls. Curiously, the Antares power amplifier is currently spec'd at 20 watts per channel (THD 5%) with the KR 842VHD tube. The VA340 integrated is also spec'd at 20 watts per channel (THD 5%), but with their 300BXLS tube. Before you think about bumping up the power of your present 300B amplifier by dropping in a pair of these BXLS tubes, do some homework on the web, or call Mr. Kayser. Chances are it won't work. KR does, however, manufacture an improved 300B tube as well as re-makes of many of the classic power tubes in use today, all of which can be used to upgrade amplifiers using their respective tube type. Pricey? Yes, but unsurpassed in quality. In a conversation with Alfred he spoke of audiophiles being addicted to the 300B tube and following each other like lemmings into the sea. I took the bait and requested both tubes for review. After all, what's another $525 on top of the loan of the complete amplifier? Surely somebody wants to know the difference the two tubes make — besides yours truly, of course.

And the other big question: Why is the preamp section solid-state? Isn't this the premier tube manufacturer in the world today? The answer will come later. For now, you probably want to know that the output triode tubes work in pure Class A, single ended, with zero feedback. A microprocessor controlled autobiasing system means you never have to fuss with tube adjustments. Selection of the four identical inputs and control of the motorized Alps potentiometer is by the infrared remote or by human touch. A red LED lights up above the selected source button and the four buttons are easily differentiated at a distance. On the back of the unit are rca inputs and an rca output for a recorder. The mains fuse is easily accessible as I found out when the amplifier shut down. After switching from a T2.5A to a T5A slow-blow fuse, the amplifier ran flawlessly and seemed a bit more dynamic. The user also has the ability to switch from 4 Ohm to 8 Ohm output with little effort. The unit can be changed from 115V to 230V operation with just a little difficulty.

The Design
So much for the nuts and volts. I've long contended that the decision to buy a piece of audio equipment is highly influenced by its visual design, so let's take a look at the KR from that perspective. In the Western world most of us can chant the mantra "form follows function" and the initial impression of the VA340 is that it is a tube amplifier. There is the huge rectangular block across the back of the unit that houses the power supply, two huge seven-sided towers that house the transformers and two huge ring towers that protect the power tubes. The seven sides of the transformer housing have no parallel sides. They are also made of heavy gauge steel and coated with a black crackle composite for further dampening. No noise comes from the hand wound transformers inside and there is no ring to the housing when it is rapped with the knuckles. In fact, in operation this amplifier is dead quiet. With the gain up full and my ear right at the drivers, I could detect no noise. And I'm certainly not the first reviewer to notice this outstanding feature of a KR amplifier.

The black tube towers are very rigid and are capped by a heavy disk with a 0.75-inch (2 cm) hole in the top, through which rises hot air when the amplifier is in operation. Imagine a miniature manhole cover with steam rising out of it in the winter. The design is obviously intentional, either controlling the convectional flow of air around the tube or protecting the tube from falling Christmas ornaments. Three hex-head set screws secure each cover, and it is easily removed for tube swapping. (Which I will do, later). In operation, the cap and the rings of the tube cage become quite hot, as you would expect, but not so hot as to burn the skin before nerve receptors have time to send a signal to the brain to remove the finger. The self-protective autonomic reaction has plenty of time to remove the finger before serious damage is done. I wouldn't, however, put the amplifier in the baby's playpen. With my vaulted ceiling I didn't notice any heat build up in the room, even in the hot summer, but in a smaller room, you might.

All five of the amplifier's towers are finished in the black crackle composite, and all are about the same height, with only the tube towers raising a fraction of an inch higher. The polished stainless steel deck of the amplifier is highly reflective, and will not show the build-up of dust as readily as the black finish might. (A soft camelhair paint brush will take care of that). But don't expect any warm, glowing fireplace effect from this amplifier. There is only the slightest hint of light coming from the tube towers — and only from certain angles. You know the amplifier is operational by the green LED of the power switch and the red LED of the input selected. The silver input selector buttons shine like diamonds in the peripheral light of my reading lamp at night. But other than that, the architecture of amplifier simply disappears into the landscape of the listening room; not even the polished deck comes to light from the listening chair.

On the sides of the deck are heavy finned heat sinks running front to back for the heat generated by the 'Class A' solid-state circuitry in the preamplifier section. The front plate is also thick, but not audaciously so. The four silver buttons for input selection are generously spaced for easy differentiation and the highly polished nickel-plated volume knob has a beveled demilune with a black dot that facilitates estimating the volume setting from the listening position. With the amplifier on the floor between the loudspeakers, the beveled face of the knob did not facilitate the tactile manual adjustment of the volume. I had to look at the knob to see where it was positioned. Of course, with the amplifier mounted higher up on a table or rack, this would not be an issue, as the knob would be closer to eye level. Since this is a motorized potentiometer, there were no detents to facilitate repeatable volume settings, but there was the advantage of minute adjustments by hand.

Beauty, as the saying goes, is in the eye of the beholder and to this eye, the KR 340 is a very masculine design that is both powerful and reserved. The visual elements are perfectly integrated and uncluttered, but the design takes no risks. That, combined with the dark appearance of the black, non-lustrous finish permits the amplifier to quietly recede from consciousness. Is this an amplifier that a woman could love? American artist Louise Nevelson, famous for her black sculptures, would have loved it. But any other woman, who could fall for a strong, handsome male model from Esquire magazine in a black tuxedo, certainly could, too. The KR exudes an air of minimalist luxury and contemporary design that make it appropriate for almost any castle in Europe or the Americas. And should your home be more humble or earthy, accept that the KR often reminded me of the Harley Davidson Night Train with its mostly blacked-out engine and transmission.

Hear Ye, Hear Ye
So, the questions are backlogged three deep:

"Does world class construction translate into world class music reproduction?"

"What's the difference between the 300BXLS and 842VHD tubes?"

And "Why is the preamp section solid-state?"

The answers are not "Yes, Yes and Yes," but the answer to the first question is. Right out of the box, starting with the 300BXLS tubes, it was immediately evident that this is a very special amplifier — so much so that I thought about calling Alfred Kayser to ask if this was a brand new amplifier or one that had already been broken in. The slight improvement I heard over the first half hour was most likely the tubes warming up and the solid-state circuitry stabilizing. Thereafter, leaving the amplifier powered up, but in the standby mode, the amplifier ramped into high quality music after only three or four minutes when turned fully on. This is a delightful feature for a tube amplifier — almost instant quality music on demand! As I said earlier, it takes only 8 to 10 seconds for the red LED to turn green, giving you the go-ahead signal to start your music.

While there was an immediate recognition that the KR was superior to my reference preamp/power amp combination, it took a while to pick apart the reasons why. Before that could happen the music reached into my chest, grabbed hold of my soul and shook it until my toe started tapping. And the music just wouldn't let go, no matter what the genre. I've heard the glorious sound of SET amplifiers before, including those with 300B tubes, but the 300BXLS and this amplifier are something else. Sure, give some credit to the JPS Labs 30 amp dedicated line and the wonderfully transparent and tube-friendly Kharma loudspeakers, but these are 20 very special watts per channel. The immediate and dominant experience is a direct connection to the music. When your toe is tapping and your attention is captivated by the music, all the audiophile jargon rolls onto the floor like marbles that have fallen through a hole in your pocket. I just sat there and listened and listened some more. Music never engaged me so completely in my home.

While the above statements might seem to answer the first question I would make a lot of people angry if I didn't come forward with more critical and analytical observations. Speaking here of the amplifier with the 300BXLS tubes, I'll offer, in no particular order, some characteristics I noticed with a more critical ear. As you would expect, the bass was a little softer and slower than the excellent midrange, but since it was also very holographic and revealing of timbre, the softness and even the slower attack of the bass notes seemed to propel the music along — otherwise, would I have been tapping my toe? Notice that I didn't say the bass did not go deep. It did — down into the lower 30's that the Kharma is capable of producing. Nor did I say that the bass was not strong. In fact, the KR completely wiped away the general notion of Kharma loudspeakers being somewhat too polite or lightweight in the bass. Having recently reviewed the very fast and very tight Escalante Design Uinta subwoofer, I can't say one approach is better than the other. Certainly, the 140-pound Uinta with its internal 500 watt amplifier is closer to the experience of instantaneous attack and bass slam heard in live music, but the Kharmas powered by the KR produce a bass line that is both communicative and enjoyable. Both approaches are valid, and you get to choose.

In the midrange, the KR brings the music alive with stunning presence — but don't worry, you will get used to it very quickly. Nor will you become bored with it. Focus, macro and micro dynamics are merely excellent, while tonality and tonal shading is superb. The soundstage is not a collection of islands with each musician performing in his or her own bubble of air, but rather a smooth continuous stage that is as wide and any I've ever experienced at home and deeper than most. Much of the sense of depth comes from the roll off in energy in the treble, making the cymbals sound more distant than the drums. While you might think this would sound incongruous with the rest of the drum kit, it never seemed so in actual listening. Perhaps this was because the focus in the treble remained sharp, even as the energy fell off. What we are listening to, after all, is merely an illusion, and we are often eager to be fooled.

The KR/Kharma combination was good for about 96 dB at the listening position, with my ears and the loudspeakers in an 8 foot equilateral triangle in my large room. The 20 watts per channel are spec'd with total harmonic distortion at 5%.

Tube amps are known to clip softly, and while I would notice it at times, the clipped peaks were followed by so much beautiful uncompressed music that I didn't mind it. My attention continually rolled along with the music and refused to dwell on trite shortcomings. This is another major clue that the pace and rhythm were also outstanding, as was previously noted by my tapping toe. Interestingly, the audience applause and noise between songs of a live performance recording were considerably more realistic and dynamic than before, as if I could see the smiling faces of the people there.

Switching over to the 842VHD tube, the voicing of the system shifted dramatically in a very familiar direction.  Without submerging the tubes in water to measure the displaced volume, I'd estimate the 842 is about eight times the size of the EL84 tube used in my Manley Mahis. The Mahis, however, use four EL84s per channel. The sonic signature of the Mahis and the KR with the 842VHD tube is very similar. Compared to the 300BXLS, the bass is tighter and the treble is both more extended and higher in energy. Notice that I did not say that the treble was tilted upward or that the amplifier was bright. You might say that it moves slightly in the direction of solid-state amplifiers, except it doesn't surrender the grain-free presentation or much of the palpability typically found in SET amplifiers. Because the treble is much flatter and has more energy, things like the striking of cymbals and the harmonics of string instruments are more prominent in the overall presentation. This seems to result in a foreshortening of the depth of the soundstage. The percussion section of the orchestra seems closer to the listener, as does the setback of the drum kit in rock music.

What you also gain with this higher energy in the treble is more accurate localization of the instruments producing these notes. With classical music, I could easily visualize the location of the various sections of the orchestra and follow with glee the way the composer created the spatial interplay of the various instruments. I felt more like I was sitting in the first ten rows of any given hall. If you prefer a more homogenous presentation, similar to sitting further back in the hall, perhaps the 300BXLS should be your tube of choice. The amount of ambient cues and hall reverberation will depend on the recording itself, or possibly the size and shape of your listening room if it is very large. With either tube you will still have a wide and well-defined soundstage at the front, but with the 842VHD, the improved focus at the upper and lower extremes will bring the music in these domains to greater prominence.

Emotionally, or perhaps psychologically, my reaction to these two tubes was quite different. The 300BXLS showered me with music that was so compelling that I could not help but tap my toe, whatever the genre. The music moved me, emotionally, even if I was unfamiliar with it. With the 842VHD the KR invited me to engage the music at a cognitive level by presenting more detail closer to what the recording engineer probably heard when he laid down on the tracks. Sometimes, if the music struck an emotional button in me, I would have an emotional response similar to listening through the 300BXLS, but this was more the exception than the rule. Listening through the 842VHD is a much more cerebral experience.

This is not a case of one tube being right and the other tube wrong. I had different preferences for different types of music. For rock, pop, folk and jazz and blues, I predominately preferred the 300BXLS. For classical, new age (electronic), and rap, I preferred the 842VHD. The 842VHD causes me to sit up straight and pay attention. I'm more on edge, leaning into the music for comprehension and playing with the interplay of musicians at a cognitive level. With the rap music (and some of these guys are really good poet/musicians) the experience can be downright scary. With the 300BXLS the music is the massage as I lean back and enjoy it. I don't have to do any work. I just sit there and let the music anoint me with pleasure. You pay, therefore you choose. Your particular tube preference for a specific genre may well be different than my own given that our historical relationship to music is likely to differ. Also consider that given that you will need one less set of interconnects and one less power cord for this KR integrated amplifier, the cost of buying a set of each tube is not as outrageous as it might seem.

Tube life, by the way, is a very long time with KR, but as with most tubes, the best listening comes in the first quarter of that lifetime. If you listen for three hours every day, you could expect premium sound quality for about 3 years.

Of course, if you drove your car for three hours a day, you could easily spend more than $20,000 for gasoline in 3 years, roughly 38 times what a new pair of tubes will cost you. A rather sobering thought, isn't it? This brings us around to the question of value.

Value
The asking price is not small change for most people. But for those of you seeking a world class two-channel system the KR340 offers a chance to get off the equipment merry-go-round by anchoring your system with a solid cornerstone. It is not an amplifier you will soon trade in. The KR offers more musical enjoyment for less money than what I use in my reference system, though to be fair my preamplifier has an outstanding phono stage. If what I've said about the KR with the 842VHD is to your liking and you simply cannot afford the KR, take a listen to the Manley Stingray. It is not as good as the KR, but it is a lot less money, and an excellent value in its own right.

And what about the third question, which I have not answered: "Why is the preamplifier section solid-state?" It is about the money; and it's also about the music. Riccardo Kron started out to make a tube preamplifier, but because of the lower standards of small signal tubes that were available, it took a lot of expensive engineering to reach the sound quality he demanded. His original KR 01 preamp was simply too expensive, so he turned his attention to solid-state. This is the pathway they have found that works, and honed it to perfection with quality parts and excellence of manufacture to bring you world-class music reproduction. In essence, this is an amplifier that produces music magnificently, and gets completely out of the way of the listening experience. I felt like I could buy this amplifier, surrender my Enjoy the Music.com^® reviewer's hat and listen happily ever after. Everything KR put into this amplifier — and more — comes out in the music. Therein lays the true value. It is well known that tube amplifiers often sound much better than they measure in the laboratory.

Let The LPs Roll...
Almost as an afterthought, I ran the outputs of my CAT tube preamplifier into the KR to play a couple of LPs. A little Janis Joplin, a little Stevie Ray Vaughn... Oh, My G-d, this amp almost raises the dead! The experiment suggests, however, that if you already have an outstanding preamplifier, perhaps the VA 320 power amplifier would be a more desirable choice. Throughout most of the review I was listening under the impression that the preamp section was active. It was not until the end when some apparently conflicting information led me to investigate further. It turns out the signal path of the preamplifier section is indeed passive, while the active electronics are used in the switching and volume control. My ignorance provided me, once again, with an unwittingly blind test. While I never felt it was the most dynamic amplifier that I've heard, neither did I think it lacked dynamics to any significant degree. And it certainly is among the most transparent windows I've had the pleasure to hear. For overall enjoyment of the music, it is hard to imagine it getting any better than this. As an integrated design it brings both beauty and simplicity of operation to the system. Maybe they will forget they loaned it to me for a few years.

Summary
The KR amplifier sits before me on the floor between the loudspeakers. Like the famous TV western gunfighter, Paladin, it is dressed in black. I hold a business card that reads: Have tubes, will rock.

Specifications
Type: Stereo integrated tube amplifier
Power Output: 20 watts per channel
Output Tubes: Two KR 300BXLS
Frequency Response: 20Hz to 20kHz (-3dB)
Output Impedance: 4 or 8 Ohms
Inputs: Four
Dimensions: 53.5 x 25.5 x 41.5 (WxHxD in cm)
Weight Approx. 80 lbs
Warranty: 1 years parts and labor, 90 days tubes