"The total potential here must be nothing less than astronomical!"

CAST (Current Audio Signal Transmission) is the name Krell has given to its novel analog connection scheme. In an ordinary audio system, signal is transmitted in the voltage domain and every component and connecting cable operates as a separate entity that interacts with the other system elements in its own peculiar way. Put as simply as possible, CAST takes advantage of Krell's Current Mode Technology (CMT) to transmit signal as current. This has several advantages -- for one thing, it causes the entire chain of CAST components to behave as if they were a single global circuit. Rather than dictating that the preamp's output be low and the power amplifier's impedance be high, which creates a situation where the interconnecting-cable's impedance can affect (even distort) the signal voltage operating the amplifier, CAST transfers current from a high-impedance source to a low-impedance load, minimizing (if not outright eliminating) the cable's effect on signal transmission. And, if you're using a CD player, the signal can be taken straight off the DACs without going through a I-to-V conversion stage. Krell claims CAST is responsible for a 6dB noise reduction alone.

The cables used for the CAST system are thin and flexible and are terminated to four-pin locking Lemo connectors (although they only use three pins in a balanced configuration). The cables cost $500 per 1m pair. All CAST components offer balanced and single-ended RCA connections in addition to those for the CAST system.

The rear panel has CAST, balanced and single-ended outputs, a remote trigger, an RC-5 remote input (for connection to hardwired RC components), a TosLink digital output, a coaxial digital output and an IEC mains connector.

The CD player is HDCD^® compatible, employing Pacific Microsonics PMD-100 decoder/digital filter. It employs four 24-bit DACs in a balanced configuration that couples directly to the Current Mode output circuitry for wide dynamic range (and CAST operation). The disc is clamped securely to the platter by way of a custom-built laser assembly, which, Krell claims, renders "superior retrieval of digital information."

The unit's remote is a hefty custom aluminum jobbie with a full complement of functions.

Despite its graceful proportions and the sheer quantity of connections packed onto its rear panel, real estate in the rear never seems cramped. From left to right, the rear panel contains: two balanced inputs, three SE RCA inputs, a tape input, two CAST inputs, a tape output, main RCA output, main balanced output, two CAST outputs, zone two balance output, zone two SE RCA output, Krell link (in and out), a 12V DC in and out, an RC-5 input, a Krell phono stage power connection, an RS-232 input and an IEC mains connection.

If you made it through that laundry list of connection options, you were probably struck by the zone-two connections -- that's right, the KCT is a two-zone preamp. It can control multiple sources and multiple rooms, so you listen critically to your CD player in your audio salon, while your wife listens to car talk in the living room. A switch on the preamp (mirrored by one on the remote) toggles back and forth between the two zones.

Now this is a nice feature if you've got a custom-installed multi-room system, of course, but what it really means is that all you need to create and control a multi-room system is an extra amp and pair of speakers (and some wire, of course). Hats off to Krell for making life so easy. Oh yeah, speaking of flexibility, if you want to use your two-channel system as a foundation for a home theater, the KCT also has what Krell calls Theater Throughput.

Of course, you're probably wondering about that name. Current tunnel? What the heck does that mean? Bill McKiegan, Krell's director of North American sales and marketing, explained that to me. "Most preamp-level signals are vulnerable to contamination on a whole variety of levels. CMT protects the signal; it's like being in the middle of a nice safe tunnel -- nothing can get through to you." OK, so that's a bit of a stretch, but what do you expect from a company named after a race destroyed by its own id?

Krell purpose-builds most of the components of the FPB amps -- no off-the-shelf parts for them. The amps all feature Krell's Sustained Plateau Bias system, which uses microprocessors to monitor the amp's input levels as well as the impedance of the loudspeakers it's connected to. As the signal levels -- and speaker demands -- change, the microprocessor adjusts the bias to maintain optimum class-A operation at all times by selecting one of several preset "plateaus." When signal levels demand a higher or lower bias level, the microprocessor switches to the appropriate plateau -- but only as long as necessary, so that overall sound quality is not affected.

"As though his ape's brain could contain the secrets of the Krell"

I initially set up the CAST system with a pair of Dynaudio's Contour 1.3 Mk II loudspeakers, but later switched over to a pair of Krell's own LAT-2 stand-mounted monitors. I connected everything using the CAST cables, only to discover later that I could also connect the components with either the single-ended or balanced connections and then toggle between CAST and non-CAST functions with a button on the remote.

This turned out to be a thankless task. It took a lot longer to make the connections than it did to determine how much better CAST operation sounded than anything else. The difference sure ain't subtle. First, that 6dB noise figure Krell claims makes a huge difference -- not only are dynamic contrasts broader, but you can hear far, far deeper into the soundstage. Things also sound zippier with the CAST connection. Not faster, exactly, but quickness and liveliness play a role in it, certainly. It's just (just?) a step closer to the real thing.

Need I say more?

"Monsters! Monsters from the id!"

Let me state up front that the complete Krell CAST system ranks among the very finest audio systems I've ever auditioned. Forget all about common knowledge concerning brand identities -- you know, those hoary old theories about how high-end products sound like their faceplates, which makes C-J sound "gold and glowing" and Krell sound "dark and thick." That was always a form of shorthand that audiophiles substituted for actually thinking for themselves.

There's nothing heavy about the sound of the Krell system. It was as lithe and delicate as it could be when I listened to Paul O'Dette's superb recording of John Dowland's Musicke for the lute [Astree E 7715], and it thundered and stormed its way to heaven re-creating Messian's Turangalīla Symphony [Teldec 8573-82043-2] as performed by the Berlin Symphony Orchestra under Kent Nagano. In fact, I'm not sure I've ever heard a system that had less sonic signature than this one -- from recording to recording there was an almost complete and total change of personality.

The positive implications of this are so obvious I need not point them out -- but be careful what you wish for, because its downside is that the real stinkers in your music collection will also be revealed in their full stankosity.

Whether you realize it or not, the sound of your system influences what you listen to. If your speakers don't have deep bass, you might listen to folk music or chamber music, but you probably won't be rockin' the house with hip-hop music. Similarly, a system that only comes alive when played loud doesn't exactly encourage you to develop that taste in Dowland's lute songs.

The fact is, most of us have systems whose colorations aren't all that extreme. Instead of pushing us toward one genre or the other, our systems nudge us toward particular discs. We're rewarded by better sound and, like good little puppies waiting for the dinner bell, we respond.

Now imagine a system so transparent that every recording irregularity is clearly audible -- what's that going to do to your record collection?

The Krell system is going to tell you the truth. I think we're all in agreement that the truth is a Good Thing, but sometimes a little sweetening is awfully nice. Don't get me wrong -- the Krell system isn't one of those over-refined thoroughbreds that highlights the flaws in every recording. That's an insidious coloration that's only pretending to be the truth -- and living with such a product is as big a pain in the tucchus as having a friend who refuses to tell a fib. You might admire it, but you'll never warm up to it.

Listening to the aforementioned Dowland recording through the Krell system, I clearly heard O'Dette in a small, hard-surfaced room. A lute's sound is a complex one -- when the instrument is plucked, it seems all leading transient, which quickly decays to a damped silence. But that initial transient is full of fleeting overtones, which pick up a little reinforcement from the instrument's body -- and that is followed, not quite instantly, by a gentler swell off the room's boundaries. Open chords not only linger slightly longer in the air (although the brilliance of the string overtones is just as fleeting), but also flow into the edges of the room, briefly illuminating them as well.

I heard all this -- a far greater level of detail than I'd ever coaxed off the CD before. (And I could lose a lot of this newly revealed information by switching out of CAST mode and even more by playing the disc on my reference Musical Fidelity A3CD). But I was in for more revelations. As O'Dette played, I could clearly hear the frets creaking against the neck and -- heavens to Betsy! -- I could hear the chirp of his right hand's fingers against the nylon, silk and silver strings. When he shifts position, the whole composition of the room reinforcement changes tone -- not a huge difference, but clearly audible through the Krell.

Yet none of this hyper detail was at the expense of the music itself. I still wanted to listen to record after record -- in fact, each CD represented a new adventure.

Turangīlila Symphony threw a vast soundstage -- it ran from wall to wall and crossed the front wall boundary completely. It was deep. And the hall sound of the BPO's Philharmonie was warm, slightly dry and immense. At the center of this supportive acoustic, the stage was awash with players, creating a gigantic sound that all but blew out the windows. The piano's "birdsongs" were brilliantly crisp and pierced the wash of sound, while the delicate shimmer of the ondes martinot seemed to float weightlessly above the strings and brass. It was a sound unlike any other I've heard. (For those familiar with the superb Previn performance on EMI, this is like a different work entirely.)

You want dynamic range? This recording goes from near silence to roof-raising ruckus -- and the Krell components delivered it all without breaking a sweat. I can't imagine actually stressing this combo with any ordinary loudspeaker (but I'll be throwing a pair of Dynaudio Temptations at it in the near future, so watch for my review of the amp by itself among SoundStage!'s future reviews).

You want to hear the power of a rock-and-roll band? Of course you do! Well, the CAST system handled that without even raising a (figurative) eyebrow whether it was the solid guitar crunch of Rodney Crowell's "Telephone Road" (The Houston Kid [Sugar Hill SUG-CD-1065]) or the high octane blues roar of Johnny Winter's Deluxe Edition [ Alligator ALCD 5609]. The sound was crisp, detailed and, most importantly, tuneful. Krell boogies like a good 'un.

"Quiet please. I am analyzing."

So, is the Krell CAST system the end to all my audio ramblings? It could be -- I could be very happy with this system. Is it perfect? Well, what is? I can still tell the difference between recorded music and the live stuff -- although that may be a transducer problem rather than the fault of the electronics. Ask me after I've demoed the Temptations.

Good as it is, the Krell CAST system may not be for you. For one thing, it's expensive. As a reviewer, I try not to put my wallet in someone else's pocket. I describe my experiences with the components and let you decide if you wish to buy them -- and price is certainly a consideration for most of us. I don't happen to have $26,000 I can spend on a hi-fi system, so I'm not the customer the CAST system is aimed at.

But if you have the money and would consider spending it on a stereo, I don't see how you could go wrong buying the Krell. It is constructed to an insanely high level of fit 'n' finish and it is based on solid, no-nonsense engineering. It looks good and it sounds great.

It's probably the finest complete system of electronics I've ever heard -- and its innovative CAST connection scheme neatly solves one of audio's most vexing problems, making it sui generis.

But be careful. The Krell tells the unvarnished truth to an even greater extent than any system I've ever heard. If you've assembled a record collection based on a particular system coloration, you may not necessarily like everything the Krells will tell you. That's OK -- not everybody can handle the truth.

But if you can take it straight and you value owning superlative engineering and pushing the performance limits -- and you can afford to insist on the best -- Krell has got the system you've been searching the cosmos for.

...Wes Phillips
wes@onhifi.com

Krell Current Tunnel Preamplifier
Price: $8500 USD
Warranty: Five years parts and labor

Krell FPB-300c Stereo Power Amplifier
Price $10,000 USD
Warranty: Five years parts and labor

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