Krell’s complement of integrated
amplifiers has just doubled: the new S-550i is a response to those who love the
neat S-300i but need more power. A lot more
The editor rarely
warns reviewers of a product’s strengths or peccadilloes, preferring that we
uncover them ourselves. Krell’s S-550i integrated amplifier, however, was
preceded by two caveats.
Krell S-550i
It might look compact,
something one would heft with aplomb and would welcome precisely because it
isn’t a huge monster of an amplifier. But because P. Miller is an experienced
weightlifter, he tends to forget that the rest of us aren’t and even he was
nonplussed by the S-550i’s 29kg (that’s 64lb, for those of us who still speak
English). He said, ‘You may need help in unpacking it.’
Monstrous power
Paul’s other caveat
concerned its power capabilities. Never one to dupe his staff into blowing up
their speaker, he warned me that, despite its size, the S-550i is ‘a remarkably
dense amplifier, probably the most self-effacing yet monstrously powerful integrated
we’ve ever tested.’ Those words echoed around my head the first time I switched
it on from standby: a nerve-wracking initial exposure which was exacerbated by
a thump of a kind to set one’s heart racing.
Beyond those warnings,
all that I was told was that it retails at $7547 and is Krell’s new ‘flagship’
integrated, replacing the FPI – the S-300i remains as Krell’s entry-level
integrated at $4220.45. The S-550i is a true ‘big brother’ – the sonic
resemblance is uncanny save for a brutal power delivery.
Interior of the chassis is dominated by
a huge toroidal mains transformer feeding L/R power amps mounted on heasinks.
There are seven pairs of power transistors per channel!
While the front panel
suggests minimalism, that’s only because all minor settings are relegated to a
menu system, eg, balance settings and input trim, which can also be accessed by
the full-function remote. If you were put off by units with 50 or more controls
– a certain Nakamichi preamp of yore springs to mind, along with a host of home
cinema amps – the S-550i will delight you because its fascia offers only source
select, volume, mute, power on/off (from standby) and a menu display.
Inside is circuitry
that recalls the S-300i and a preamplifier section that can be used on its own
via a pair of phono outputs at the back, and which is said to boast circuitry
derived from Krell’s top-of-the-line Phantom preamp. The recipe reflects
long-standing Krell practice, with the company’s proprietary Current Mode
technology, discrete direct-coupled circuitry in balanced topology, and
individual power supply regulation. Much of the weight is attributed to a
massive 1750W toroidal transformer that shifts the weight of the amp toward the
front.
Other circuit details
include: no negative feedback used ‘or required’; a volume control consisting
of a balanced resistor ladder; one set of balanced XLR inputs along with four
single –ended phono inputs; plus a dedicated iPod/iPhone dock. Krell supplies
the necessary dock, so there will be no tears for those who arrive home with
this chunk o’ metal, eager to hear what it does with an iPod, only to find a
lack of a dock. This unit is ready to handle whatever you want to feed it.
As the
conservatively-rated 275W/ch power output all but doubles when speaker
impedance is halved, this begged to be connected to the Apogee Scintillas. I’m
deliberately not reporting what happened, but I will say that I’m no longer
pessimistic about that speaker’s future should there ever be a shortage of
circa- 1983 Krells on the secondhand market.
But that was then and
this is now. Krell was one of the first companies to embrace the custom
installation market – despite this unit being a deliciously purist two-channel
product, its rear panel offers 12V trigger sockets, RS232 and ‘Theater
Throughput’ connectivity. It even comes with rack mount ‘ears’ for housing in a
professional stand. Various parameters can be customized via the menu system.
Aside from the
worrying switch-on thump, the S-550i is easy to set up. I used it with an iPod
Classic, the Marantz CD-12/DA-12 in balanced mode and Wilson Audio Sophia 3
loudspeakers.
Nothing taxes it
Where to start? When
the promise of unbridled power is dangled in front of a hi-fi casualty, all
manner of dark, fell practices cross one’s mind. Fortunately I am both too
sensible to want to destroy a brace of tweeters and too conscious of what
tinnitus would do to me should I play with all of this amplifier’s power into
the more than willing Wilsons. But, damn, this can swing from soft to loud with
the graceful progress of a Bugatti Veyron’s W16 climbing to its kilo-ponies.
So, did I dig out
Mountain’s ‘Mississippi Queen’? Some Iggy, some Ozzy, some Lemmy? – Nothing of
the sort. I tested the Krell, during the first moments, with the antithesis of
such as onslaught: Eleanor McEvoyo’s ‘God Only Knows’ from If You Leave…
[Moscodisc MoSCD4010].
A perfect front panel for those who hate
clutter, the S-550i’s contains just buttons for sources and mute, on/off from standby,
volume and a menu to access lesser commands.
I needed to learn I
the Krell could handle delicacy as well as it would (without question) cope
with head banging abuse. After all, a Veyron can burble along in traffic
without stalling or overheating.
It is an invigorating,
rewarding and even life-affirming experience to find that one’s preconceptions
are 1800 out of synch with reality if, of course, that 1800
shift is positive rather than negative. No brutality, no coarseness, and no
lack of finesse: the S-550i placed Ms McEvoy in the room her piano tinkling and
resonating with the realism I take for granted from the Audio Research REF75,
in all its tube-y glory. This was a solid-state amplifier free of the brittle,
of the glassy, of the jarring.
Of course, we are so
far down the path of the transistor’s evolution that any throwback to
solid-state hardware of the 1960s would never be allowed to escape from its
maker’s warehouse. Indeed, it was Krell’s earliest Class A designs that set
(and for some maintain) the standard by which transistor amplifiers of robust
output should be judged. The sound of this minimalist recording, of a voice I
have heard from but two feet away, was as satisfyingly real as one could hope
to experience.
“I Want To Ta-Ta You Baby” was pure,
liquid blues – salacious, smoky’
Because of its very
refinement, the recording hardly taxed the Krell, any more than it had ‘worked’
the Micromega MyDAC before [HFN Jun ‘13]. What the track asked of the S-550i
was to reproduce its detail, spatial concerns, texture and authentic tonality.
The performance never demanded of the Krell a swing from soft to
ear-shattering. But it did expect the S-550i to remain as poised and as
composed as the performer.
Delicate keyboard
fingering, matter-of-fact vocals possessing a unique charm, to contrast with
the import of the lyrics – pure emotion oozed from every note, but free of
melodrama. So, too, did the Krell remain collected, unruffled, and even suave-
if an amplifier can exhibit such a trait.
Much as I wanted to
stick to that disc, I couldn’t resist the edgy, scorching axemanship of Johnny
‘Guitar’ Watson’s ‘I Need it’, two-and-a-half-minutes in, and preceded by
punchy horns and a percussion opening that surely must have been sampled by seven-figures’
worth of copyists. The stand-out from 1976’s Ain’t That A Bitch [Sequel
NEM CD 774], it features staccato playing so evocative of that era, all Superfly
and wide lapels and huge shades.
In addition to multi-way speaker
terminals, four unbalanced line inputs and one balanced input, this unit
accepts an iPod dock (supplied), a complement of home automation inputs and
main power on/off in the upper right corner.
Punch, attack, crisp
edges, no decay- the Krell managed every sweep of brush on cymbals, the fast
plucking with a hyper – metallic edge. And yet the next track, ‘I Want To Ta-Ta
You Baby’, was pure, liquid blues – liquid blues – still with the cutting snap
of the strings, but slithery, salacious, smoky. A perfect horn section, mixing long,
airy sighs with decisive punctuation, the Krell arrayed it behind Watson;
creating a backdrop with the curve of Venus’s shell, but wider and taller. It
was a perfect, seamless, Spectorian wall of sound, only stretching from wall to
wall, rather than throbbing as a round mass in the center.
