Amp/Preamp Asylum: REVIEW: Krell KAV-280p Preamplifier (SS) by readargos

Model:	KAV-280p
Category:	Preamplifier (SS)
Suggested Retail Price:	$3500.00
Description:	Linstage Preamplifier
Manufacturer URL:	Krell

Review by readargos on August 03, 2014 at 16:09:50
IP Address: 67.175.6.2 Add Your Review
for the KAV-280p

Wes Phillips said it best in a review at OnHiFi.com: since its founding, Krell has become both a bellwether and a stalking horse for the high-end. Much like the mythical race after which the company was named, an air of mystery surrounds the brand. In both professional magazine-published reviews and those found by innumerable users on the internet, the brand, and its sound, has a polarizing response. Krell has been described as both sweet and harsh, bass heavy and lean, warm and cool, bright and dark, dry and liquid, mechanical and organic. Can it be all these things? Is it such a neutral, and perfect, conduit that it merely shows up the shortcomings of the ancillary gear with which it is used? Or does it, rather like the machines invented by that superior race of science fiction lore, reveal listening biases in the souls of those who hear it? While I’m not sure I can answer these questions, subjective as the hobby can be, I will address them in the context of this review.

I have hardly heard every Krell component, but many audiophiles agree the company reached a high water mark at the turn of the century with its revamped FPB line of amplifiers and Current Tunnel preamplifier featuring current mode signal transmission, taken to its ultimate conclusion with CAST connectivity. Most of this technology, with only slightly less fanatical implementation, trickled down into the “Architek”-style KAV components under consideration. The major areas of “compromise” on the preamp are no multi-zone control, and fewer balanced inputs/outputs. On the power amp, the output stage is Class A/B, with no Sustained Plateau Biasing. Nor do the KAV components have CAST amenities. But the preamp is fully balanced right through the digitally-controlled resistor ladder volume (and it’s not as “hot” as the volume on the Home Theater Standard pre/pros of the same era); and the amp has Class A input, pre-driver, and driver stages, a massive 2,000 VA transformer (compare the transformer size to similarly-rated amps from other manufacturers), with an output stage that runs on the hot side of warm, indicating a higher Class A bias. Although built to a price point, and designed for custom installations with their cooler operation, it is otherwise hard to call these compromised components.

I started the evaluation with the KAV-280p preamplifier in the chain running single-ended. From cold, it seemed to offer up more low-level detail with increased depth and transparency (as though removing a fine scrim), but was lacking in dynamics and body. It improved a little in an hour, but really seemed to reach its stride after being plugged in for about 24 hours. (Some of the circuitry remains powered in Standby mode.)

In my experience, something happens with Krell gear after it has been on a while. The sound remains fairly consistent between a cold start and fully warmed up, but fully warmed up, the sound becomes more engaging. There’s a little more warmth and naturalness, but you don’t hear it so much as sense it.

Fully warmed up, the preamp exhibited good texture (instruments sounded more like themselves; more like the wood or metal or skin they were made of) with sonically dense aural images. The soundstage width grew to match the newfound depth. Retrieval of low-level detail continued to impress (there was no unnatural highlighting), but the soundstage was broad and deep and the overall presentation slightly laid back. Thus, dynamics and attack (punch) were not class-leading, despite more deep bass. Although it was some of the airiest Krell gear of my experience – an area that Krell continued to improve with its EVO and S-line of products – it was nevertheless less airy and less harmonically rich compared to tubes and some solid-state. Though balanced connection improved the air somewhat, the trail of notes died out faster than the best I’ve heard. It seemed more focused on the fundamental of a note in building its sonically dense imagery, while sacrificing the bloom and harmonic overtones that tubes and other good solid-state deliver. Unless fully warmed up, the Krell had a hint of coolness that I felt was colder than strict neutrality (i.e., reality). On the other hand, the sense of music emerging from a black background was improved, which (I suspect) aided the more lifelike rendering of low-level detail. In the concert hall, for example, you hear everything, even with distant seating. One of the areas where home playback can fall flat is the loss of this very low-level detail, at least at levels that are realistic, or comfortable, for the louder passages. I found the increased sense of quiet and low-level detail puzzling, because with other preamps in the chain, the speakers’ tweeters were dead quiet; but with the Krell, I perceived a low hiss as much as 3-5 feet away. However, at the listening chair, the low-level hiss was masked by the ambient noise of the room.

In many ways, the 280p was as good or better than other gear of my experience: low-level detail, soundstage width and depth, deeper and tighter low bass with great pitch differentiation, and texture, which made it easier to identify which instruments were playing in a dense mix. It was also good at conjuring palpable instruments, but, because it was more laid back, seemed less successful at conjuring palpable singers and a palpable recording space. Singers were more distant and the air seemed stuck in the rear of the stage instead of billowing toward the listener. In that sense, particularly with instruments, the presentation was more they-are-here (the instruments have inhabited your room) than you-are-there (you have been transported to the recording venue). The extra transparency aided the sense of instruments inhabiting the listening room, while the loss of air detracted from the sense of being transported to the recording venue.

Some good solid-state of my experience offer a good measure of the harmonic richness, instrumental overtones, and palpable air and bloom of tubes. When an orchestra swells, it can catch you up in a riotous swirl of sound. This is a beautiful and exuberant sound. Often, it's a little brighter, giving the sound lift (the sense of a rising treble component on the note’s tail) with a long decay. Lift aids bloom and billowy air. By bloom, I mean the sense of instruments or vocalists being surrounded by a halo of air that grows and builds in proportion to the loudness at which they’re playing. Billowy air is related: the collective bloom of an orchestra in full cry, for instance, sends waves of sound surging toward the listener. When the music stops, there’s a palpable decay as the notes die out and the hall absorbs the sound. This brighter, more colorful sound, often coupled with a more forward presentation, seems to convey more vocal nuance and expressiveness. It emphasizes a bit more angst or sadness or yearning in the strings. However, as with tubes, it can also overlay the sound with a subtle whiteness or fine mist – the halo of the bloom – that limits ultimate transparency. It can also cause a slight blending of the sound of certain instruments, particularly high woodwinds and violin/viola that makes it more difficult to distinguish their individual sound. When well executed, it is not a pernicious sound. As I said, it can be very beautiful, very attractive, and has many elements of sonic truth.

The 280p does not do this. There is no whiteness, there are blacker backgrounds. The system loses a bit of airiness, decays shorten, harmonic overtones are less complex, bloom lessons. It’s a drier sound, but it has an absolute crystalline clarity. It is superbly controlled, particularly in the deep bass. There is no mid-bass emphasis or overt warmth, and consequently the system, while having more deep bass, loses a sense of slam. On the positive side, there is no homogeneity. The sound gains density and texture. There is greater differentiation between woodwinds within an orchestra. It’s a bit easier to identify sources of sound with the Krell pre. Things sound more like themselves, more specific, more organic, more eerie real, and, in some cases, more alarming. (Did that sound come from the recording? Or somewhere in the house? Or somewhere outside?) It excels at small-scale jazz where you get a greater sense of each player’s contribution, and how they feed off what the others are doing. It is also a wonderful tool for comparing different interpretations of the same classical pieces, because it highlights choices in the conducting without being ruthlessly revealing. When strings are being used to create tension, the 280p expertly conveys that tension. In combination with its almost eerie quiet comes a sense of surprise, in that you don’t know what’s going to happen next. It’s a thrilling sound with all the suspense of hearing a piece of music for the first time. It can sustain this suspense even on familiar material. It builds a sense of anticipation that, I think, mildly elevates the pulse. Its deep bass better conveys the menace and dread of music. Try Varèse’s “Arcana”, for instance (with Leonard Slatkin and the Philharmonia Orchestra, RCA Red Seal, packaged with one of my favorite interpretations of Holst’s “The Planets”). Whereas some solid-state gear is designed to sound beautiful, the Krell is designed to sound real.

But here’s the rub: the sound of a real orchestra has all the elements of both camps. It sounds solid and dense, but also rich and airy, warm and bright. Perspective varies with seating, whether the sound is bigger and bolder and more forward, or more distant, but I think most of the other elements are constants. Although it’s convenient to think of it in such terms, “distant”, in a real hall, does not necessarily mean relaxed or laid back, because there is something about live music that engages us and we still have that sense of hearing every little detail. So, the Krell is designed to sound neutral and accurate, and brings a level of control, low-level detail, and deep bass definition and differentiation that resembles what we hear live, elements that other gear in this range only aspire to. Yet, its slightly cool, laid-back perspective fails to engage on a different level. It lacks charm. The 280p will keep us listening because it’s an impressive sound. In those ways in which it sounds real, I’ve heard nothing else quite like it. For many listeners, this will be enough. For others, though, because the sound is controlled and lacking mid-bass warmth and bloom and billowy air, it seems distant, cold. It sometimes misses that toe-tapping variety of timing, that kind of attack on the beat and a sense of spontaneity and joie de vivre we enjoy in live music. Its achievements are admirable, and intellectually engaging, mysterious and suspenseful, but not necessarily loveable. These listeners may enjoy spending time with the 280p, but will not find enough sense of fun to keep them in a committed relationship.

With this in mind, I’ll examine some of the commonly reported criticisms and observations of Krell sound.

BRIGHT, MECHANICAL, or HARSH. I think “bright” is actually directed at the slight leanness of the sound, the lack of overt warmth, and not high-frequency performance per se, because I’ve always found the classic Krell sound, if anything, slightly dark. “Harsh” or “mechanical” could be directed at how the Krell sound pressurizes the room, especially when used with its companion amplifier and dynamic speakers. Even at low volumes, the pistonic movement of the drivers raises the sound pressure in the room. The control exerted over the drivers creates a kind of staccato sensation, like the fire of a machine gun. This is exemplified by some of the classic Krell pairings with speakers that need control: large panels like Magnepan or Apogee, more romantic speakers like older Sonus Faber, and piggish loads like older B&W 801s and large Thiels. Such speakers result in more satisfactory pairings for many listeners.

My take is that Krell treble is precise. It is smooth and consistent, and imparts no artificial edge or glare. However, it is not creamy and exhibits no sweetness. There is no mildness or diffusion as you get with some transistor or tube designs. Diffusion, I think, aids sweetness and bloom. It gives the sound sheen. Diffusion, combined with lift, can also give a sense of extension of top-end air: there is the instrument’s fundamental, followed by the harmonic overtones. With cymbals, gongs, or triangles, the sound can expand toward you with the bloom. Restrained treble dynamics or a rolled off top perhaps give a creamier texture. Krell gear will accurately convey the intensity with which a jazz drummer hits or brushes cymbals to create mood and atmosphere. The sense of a wooden stick hitting a metal high hat, and the tightness of a snare on small-scale jazz is addictive through the Krell. You can have dynamic treble with bloom, sans harshness; but it’s rare at this price point.

LEAN or TOO MUCH BASS. I think most electronics, particularly in this price class, have varying degrees of midbass boost. Depending on implementation, it can add anything from mild warmth to slam. This is an attractive sound, so why not implement it in the voicing? First, I think midbass exaggeration typically spoils a sense of depth. Not completely, but when you have a frequency band that jumps forward in the soundstage, imaging specificity and the anchoring of instruments within the stage may be spoiled. Drums provide one good example. In many recordings, classical, rock, or jazz, drums are center rear. The slam factor provides immediacy and excitement through physical impact. However, if those frequencies jump forward, the drums will not be anchored, and the sense of depth is spoiled. Too much warmth can also blur the sounds of drums with electric or acoustic bass. Piano, because of its frequency range, is another acid test. You can probably count on one hand the number of systems you’ve heard that present a physically palpable instrument that remains solidly rooted on the virtual stage from the left- to the right-hand registers. You can have it all – warmth and slam and stage depth – but again, it’s rare at this price point.

The second criticism is that Krell has too much bass. The sound of better Krell gear has a granitic solidity, a real physical weight that does a remarkable job of conjuring not just aural images, but the actual sense of physical objects inhabiting the sound field with great density and specific texture. The better Krell gear is not bumped up in the midbass, but, compared to most electronics, seems to be bumped up in the sub-bass.

I believe this explains the apparent contradiction, depending on one’s listening perspective, that Krell is both lean, yet has exaggerated bass. It sounds lean compared to most electronics because there is no midbass bump that warms up the sound. Moreover, certain iterations of Krell gear may actually be a bit lean. But Krell is not trying to sound attractive (which usually adds a certain, if subtle, homogeneity across recordings), but accurate. It sounds bass heavy because the low bass is more noticeable, to a remarkable extent, compared to most electronics. When I did these comparisons, for instance, I disconnected the subwoofer, but with either amplifier, the Krell preamp’s sub-bass attack and control and differentiation was like adding a sub back in – a very good sub.

The Krell is highly responsive to change in cabling, and I found I was able to tune the sound in a way that mitigated any shortcomings I heard. Running balanced gives slightly lower noise, more air, better low bass, and a wider (if not necessarily deeper) stage. Running a complete Cardas cable loom gives a bigger and bolder and more forward sound with more mid-bass richness, attack, and slam. It beautified the sound a lot (more warmth with richer harmonic overtones and longer decay) while maintaining everything I liked about the Krell already - not sacrificing transparency or imposing whiteness or mist, nor ruining depth, nor losing texture. In fact, the sound gained more density. It upped the emotional involvement and the expressiveness of the system. Especially when used with its companion KAV-2250 power amp running in balanced mode, it did not merely soundstage well, but had the ability to impose the recording venue on the listening room. Width was not restricted by speaker spacing, nor was depth restricted by the rear wall. In direct comparison, it still wasn’t the airiest or richest solid-state gear, but taken on its own terms, and well warmed up, the presentation seemed sonically complete.

Whether other listeners like the effect of a particular cable loom is beside the point. Rather, I think it speaks highly of the innate transparency and neutrality of the 280p: if you like how it sounds out of the box, you can tune it to a fair-thee-well! “Like” could become “love”. Moreover, it reveals that system context is a greater factor than usual when evaluating this gear. Perhaps that, above all else, explains the oft-times contradictory reports of Krell sound in various review sources.

Even though I obtained best results for my preference running Cardas, my impression still was that Krell sound is built from the bottom up, while being a little dark on top at the sacrifice of air and bloom and palpable decay. The Krell bass has more solidity, and seems almost thick enough to cut with a knife. While the Krell seems more transparent and more clear, in direct comparison, I often wondered if this was a result of a slight leanness that allows detail to be heard more easily and emphasizes depth, but at the cost of weight in an orchestra’s power range that we hear in real life.

This tendency toward leanness does not mean it’s harmonically threadbare, but the harmonics are not as fully developed as some tube and some solid-state designs. Its focus on instrument fundamentals emphasizes tight pitch control versus a thicker, warmer (and some will say, more lifelike) measure of reverberation. Cello and bass are well-rendered without being supremely resonant, but violins tend toward steely. It’s not a harsh or aggressive sound, just a bit thin. It serves other instruments well, however, highlighting the contribution of woodwinds in an orchestra, and giving a palpable tightness to snare drum. With its leanness, the Krell sometimes sounds more detailed and better in the low bass, while the lack of any midbass emphasis, and especially punch, could be leanness that departs from real neutrality. While it could be argued the difference is one of perspective, a real orchestra has weight and warmth in its power range. I’m not just talking tympani, which the Krell does well, but when all the strings dig in, there’s a weight to the sound as it loads the hall.

The good thing about the leanness is the way it highlights orchestral detail and provides an openness to the soundstage that reveals orchestral layering and lets you hear clearly to the soundstage rear. Concomitant with the excellent low bass and a discipline and control that keeps everything anchored solidly within the virtual stage, is a sense of cavernous depth. The stage extends far back, convincingly beyond the room’s rear wall. Even on orchestral crescendo, everything stays rooted. Some listeners will enjoy this aspect, but others will hear it as too polite. The brass, in particular, seem too controlled. It remains rooted, with a suitably metallic sonority, but fails to rend the air the way I hear it live, at least with close seating.

There is no glare or etch, no hardening of timbre at any reasonable volume I achieved. It’s always controlled, relaxed, laid back, effortless, but seems to lack the highest-level dynamic contrasts. There is no sense of ever really cutting loose, of swinging really hard, even when the music would seem to demand it. However, you’ll have to be used to something better to catch the Krell out on this count.

In my opinion, the 280p was one of the real sleepers in Krell’s KAV line from the last decade, probably because of the lack of reviews in the U.S. audio magazine press. Frankly, it’s hard to find a solid state preamp this good at this price. Summing, up, the 280p offers a huge soundstage with real depth, fine resolution of detail, deep bass authority, and a complete sense of ease. On first listen, other than than the bass and wealth of detail, it seems like it isn’t "doing" anything. However, after longer exposure, you realize that’s what a preamp is supposed to do - expand dynamics and soundstaging without sacrificing transparency - and you’ll appreciate how good this unit is. In my experience, it benefits from considerable warm-up to showcase full harmonic development (at least, as full as it gets with this preamp) and instrumental solidity on the virtual stage. If I had to compare it to orchestral compositions, I would pick those of the Russians: it’s dense, yet bleak, and, of course, mysterious. If I had to compare it to cables I’ve heard, I would pick AudioQuest as being most comparable to Krell’s take on neutrality.

The Krell sound is, indeed, impressive. Whether you like it, it’s different enough from most electronics to highlight the strengths and weaknesses of other gear, and thus reveal one’s own listening biases. That’s not a bad thing. At the same time, the preamp is such a neutral conduit that it’s highly responsive to changes in associated gear. If you like instrumental texture, image density, low bass authority, a huge soundstage with real depth, a clarity that allows you to hear low-level instrumental detail, and a sense of discipline and control that preserves orchestral layering and keeps everything firmly rooted on the virtual stage, then the 280p is a must-hear. No, it won’t appeal to all tastes. There’s other gear out there for this very reason. But I believe your audio journey will be better for having heard it, because it will show up precisely what your current gear does and doesn’t do, and allow you to identify, and perhaps come to terms with, your own listening priorities. You will have learned something along the way: the secrets of the Krell.

Product Weakness:	Not as airy or harmonically rich as some; macrodynamics will seem too controlled/polite for some listeners.
Product Strengths:	Crystalline transparency, low-level detail, deep bass authority, image density & texture, ergonomics.

Associated Equipment for this Review:

Amplifier: Krell KAV-2250, Musical Fidelity A308cr
Preamplifier (or None if Integrated): Musical Fidelity A308cr
Sources (CDP/Turntable): Rega P3-24 with Ortofon 2M Bronze, Tangospinner RP6 subplatter and RP6 glass flywheel platter, Musical Fidelity A308cr
Speakers: JMlab Electra 915.1
Cables/Interconnects: Cardas Quadlink & Neutral Reference
Music Used (Genre/Selections): Classical, Jazz, Electronica
Room Size (LxWxH): 17 x 12 x 9
Time Period/Length of Audition: Owned
Type of Audition/Review: Product Owner

Amplifier:	Krell KAV-2250, Musical Fidelity A308cr
Preamplifier (or None if Integrated):	Musical Fidelity A308cr
Sources (CDP/Turntable):	Rega P3-24 with Ortofon 2M Bronze, Tangospinner RP6 subplatter and RP6 glass flywheel platter, Musical Fidelity A308cr
Speakers:	JMlab Electra 915.1
Cables/Interconnects:	Cardas Quadlink & Neutral Reference
Music Used (Genre/Selections):	Classical, Jazz, Electronica
Room Size (LxWxH):	17 x 12 x 9
Time Period/Length of Audition:	Owned
Type of Audition/Review:	Product Owner