I upgraded from the Krell 400xi to the KW500 over a month ago. The improvement in resolution, imaging, speed, and a solid sound stage was easily picked up. The 400xi sounded good with adequate bass and decent resolution, but the bass and percussion did not have a realistic impact or speed which made some music sound slower and less involving than it should. The KW500 pretty much erased this problem and made percussions sound crisper and cleaner with hard hit drums or symbols startling you when before they were just background noise on the Krell. The improved percussion allows the artist's intended rythym for the music to come out alive. What really hurts the 400xi is its limited resolution and slight darkeness which the KW500's tubes cleaned up in spades. Subtle details that were smoothed or muddied over by the Krell were finally revealed with the KW making the music more life like and 3 diminsional. The KW revealed beautifully the brillliant multiple string layerings on the 9th symphony Molto Vivace movement to the quiet subtle inflections of Joan Baez singing on the Farewell Angelina album to clean dynamic guitar strumming from Led Zeppelin and Van Zandt. This higher resolution balanced with tube warmth makes listening to reproduced music so much more enjoyable. Notice I haven't metioned the brute wattage power the KW happens to have because it doesn't come to mind. The KW applies the power discretely as to not overpower the music at reasonable listening levels and help preserve resolution by never sounding strained. If you turn the volume too high, the sound will sound hard and harsh, but I that that is the case with probably all amplifiers.
BACKGROUND: I've had the Musical Fidelity KW500 for a couple weeks now. I've been playing it exclusively through a pair of Magnepan 1.6QRs. (I'm awaiting delivery on a pair of 3.6/Rs, and bought this amp specifically for that reason.) The speakers are bi-wired through a set of Speltz magwire "anticables." The amp has four speaker terminals on each side specifically for bi-wiring, so I decided to just take advantage of them and not worry about the minor addition in cost and whether this really improves the sound noticeably.
The signal source is a Benchmark DAC1, fed by a Slimdevices Squeezebox 2 run digitally through a Behringer DEQ2496 equalizer for room correction. About 95% of my music collection is ripped in FLAC, and it's heavily weighted towards electronica (but NOT techno), with a healthy dose of modern rock, punk, jazz, funk, classical, and a little bit of everything else under the sun.
My room is about 15' x 20' with wood floors, an area rug, and a fair amount of furniture. I tend to listen at fairly high volumes most of the time, thanks to a cool wife and neighbors.
THE UNIT: In summary, it's a hybrid integrated amp with about 500wpc at 8 ohms. The preamp is tube driven with military-spec tubes that are supposed to last a lifetime.
The amp is constructed in two pieces: The power section has its own separate housing, and it connects to the main unit via three umbilical-type cords (one for the preamp, and two for each side of the power amp). Together, both sections weigh 100 pounds!
The fit and finish on this equipment is simply unsurpassed. I've owned Musical Fidelity gear before, and I've certainly found it to be well-constructed, but this thing is just ridiculous. I'm not kidding; it is built like a ****king tank. I understand most of MF's stuff is manufactured in Asia now, but this line is still built in Britain. I believe it. This thing could have survived a few dozen Nazi air-raids and then some.
The volume knob on the front of the main unit is about 3.5" in diameter, and turning it feels like rotating the dial on a 500-pound Acme safe. Each section has two large, black handles(?) on either side of the front that don't really work as handles, so I don't know what purpose they serve, other than to make it look tough. (Maybe you can rack-mount it somehow, but it's hard to imagine, quite frankly.)
The appearance won't win any beauty pageants, unless they're held in East Germany ca. 1970, but I don't mind it personally. The only semi-attractive parts are the lit-up feet on each unit. They start out red when you power up, turning to amber after 6-7 seconds, and then to electric blue after warming up a half hour or so. They're kind of gimmicky, and I personally can't tell any difference in sound between the amber stage and the blue stage, but I'm sure some people will take special satisfaction in know their music is playing at the right color.
SOUND QUALITY: In my opinion, and in my setup, the sound quality is absolutely astounding. This amp will clearly not be to everyone's tastes. It is *extremely* aggressive with dynamics and transients. Many listeners will undoubtedly prefer a more laid-back, smoother, more "musical" sound. But personally, I have never heard anything so attention-grabbing and realistic sounding. This is music that grabs you by the ears, and forces you to listen. And I love it!
The tone is perfectly neutral and crystal clear. Initially, it seemed too bright at times, but I was able to work with speaker placement to ensure it didn't become unpleasant with mid-treble-heavy music like horn sections, etc. I suspect I was simply getting some badly placed reflections off the walls, furniture, etc. Now it sounds absolutely perfect.
The level of detail from this combination of amp and speakers is like nothing I've heard. I constantly find myself doing double-takes when a certain sound seems "right there" in front of me with an uncanny degree of realism. The soundstage is wonderfully wide and deep, despite the fact that I'm unable to position the speakers optimally because of how the room is laid out.
The bass is the best part. It is extraordinarily rich, utterly satisfying and downright earth-shaking given the limits of these speakers. Standing between the speakers at loud volume, I can feel the floorboards flexing beneath my feet. People had told me not to expect more bass out of a more powerful amp. I expected them to be right, but now I've concluded that they are simply wrong. This thing actually makes my 1.6QRs punch like a welterweight. They sound distinctly un-Maggie-like in this department. They aren't quite like JBLs, but for the first time, I can really feel the bass substantially, like I could never feel it with other amps driving these speakers.
Before this amp, I'd been driving the 1.6QRs with a Pathos Logos with 220wpc @ 4 ohms. I thought for sure that was plenty of power, but now I don't think so. I've heard many people say Maggies need loads of power to sound their best, and for my tastes, they're absolutely right. Some folks say you can drive Maggies with a few high-quality watts from a tube amp, and if what you want is a pleasant, musical smoothness at low volumes, then that's fine for you. But if you want serious dynamics and attention-grabbing realism at loud volumes, you really need serious power.
THIS IS MY THIRD MUSICAL FIDELITY INTEGRATED AMP AND THE BUCK STOPS HERE.THIS IS A VERY AMAZING AMP AS FAR AS SOUND QUALITY GOES,TREMENDUS AMOUNTS OF POWER 770 WATTS INTO 4OHMS.I AM USING THEM TO PUSH A PAIIR OF MARTIN LOGAN PRODIGY'S,NO PROBLEM. EVERY BIT OF INFORMATION THAT WAS RECORDED GOOD OR BAD WILL BE RETREIVED AND REVEALED THRU THE KW. NOT ONLY GREAT SOUNDING TUBES IN THE PRE-AMP STAGE,BUT ALSO VERY DURABLE WHICH IS GOOD BECAUSE I LEAVE THE AMP ON PRACTICALLY 24-7 TO KEEP IT IN THE RIGHT THERMAL CONDITION, READY FOR ACTION AT ALL TIMES,STAYS WARM BUT NOT HOT,WHEN RUN AT VERY LOUD VOLUMES, LOUDER THAN NORMAL LISTENING LEVELS AMP GOT HOTTER THAN USUAL BUT THE MAGIC NEVER ALTERD IN ANY WAY, IF ANY THING THE AMP SOUNDED BETTER.I HAVE EVERY CD THAT PATRICA BARBER EVER RECORED,IT SEEM LIKE I AM HEARING THEM AGAIN FOR THE FIRST TIME,I HAVE OVER 2000 CD'S A KW500 A PAIR OF MARTIN LOGAN PRODIGYS,A SONY SCD777ES & SONY SCDXA9000ES MUSICAL FIDELITY TRI-VISTA DAC 21, I'VE BEEN TO THE MOUNTAIN TOP I'VE SEEN THE PROMISE LAND.
Well not to put a lot of words into "Fluff" To simply put it, this is one of the best Int. Amps ever and, and one of the best I have ever heard. Been a non-snob Audiophile for many years and I acutally enjoy the music I listen to, too many people get caught up in the equipment, which sure does help, but this KW-500 is like a Sonic Tunning Fork, and every little note and detail you can pick out. If your looking for one of the best Int. Amps on the planet, look no further, Musical Fidelity hit a home run out of the park with this unit. So sit back turn on the 500 and watch the feet glow from amber to blue and then sit back and enjoy!!