In the course of hunting down promising equipment for
review, I spent an afternoon with Joe Cutrufelli, proprietor of JC Audio
in Vallejo, California (http://www.jcaudio.com).
After I expressed my dissatisfaction with much of the triode amplification
I had heard in show settings, save for the ultra-expensive LAMM gear and
less expensive offerings from ART Audio, Joe told me that the Kora Galaxy
triode amp was a step above most of what I had auditioned. On his
recommendation, I contacted Kora for a review sample of the Galaxy
I have since spent three extended periods auditioning
the Galaxy. My first listening experience took place when my Bruce Moore
Companion III preamp was equipped with its original shunt attenuators,
resistors, and capacitors, and my Talon Khorus X speakers had not been
upgraded to their current state. The amp to which I compared the Kora
Galaxy was the Bruce Moore Dual 70, which lists for roughly the same
price. Both units were auditioned using RCA-terminated Nordost Valhalla
interconnects between preamp and amp.
After my initial listening sessions, I questioned
whether the Jan Philips 6922 tubes that came with the Galaxy Reference
were making the best case for its presentation. I have tried these tubes
in both my preamp and amp on numerous occasions, and have consistently
experienced that, despite their fine midrange, they truncate high and low
frequencies. After sharing my reservations with Joe Cutrufelli, I drove
the amp to his place and switched to Sovtek 6922s. For an explanation of
what adjustments were necessary to make this switch, see “Set-Up” below.
All subsequent auditioning occurred with the Sovtek 6922s in place.
While we were together, Joe told me that, in his
opinion, I would experience a 20% increase in bass response from the amp
if I listened in balanced mode. Since the Bruce Moore preamp cannot accept
balanced (AES/EBU) interconnects, I set about securing the appropriate
equipment to make auditioning in balanced mode possible.
The second listening sessions occurred after the
Companion III preamp's shunt attenuators had been upgraded to series
attenuators, affording better sound. I was also able to audition the Kora
Galaxy in balanced mode via the loan of an Atma-Sphere MLS-1 preamp and
Acoustic Zen Silver Reference balanced interconnects. During this period,
I also upgraded my amp to a hand-wired Bruce Moore Dual 100 that lists for
$6,000. Finally, I secured Telefunken 12AU7 tubes for use in both the Bruce
Moore and Atma-Sphere preamps.
My final listening sessions, after which this review was
written, took place many months later, in the spring of 2003. A thorough
revision of the Khorus X speaker, including installation of a completely
new crossover, different wiring, different braiding configuration for the
wiring, changes to the woofer cone and compartment, and modification to
the supertweeter, left me confident of my conclusions. This major upgrade
completely opened up the sound, making it far more detailed, transparent,
three-dimensional, and lifelike.
With each upgrade, I was able to hear further into the
sound. Regardless of these major improvements, however, my opinion of the
Kora Galaxy remained relatively constant throughout the upgrade process.
The Galaxy arrived chez Serinus after it had been fully
checked out and declared in 100% working order. The bias of each tube
receptacle had been pre-adjusted for a specific tube, and that included in
the shipping carton was a drawing of the tube layout, identifying each
socket by a number that matched numbers penned onto the tube boxes, so it
is important to note the prescribed position of each tube before inserting
them, since they will fit in several sockets.
When my initial audition proved less than satisfying, I
brought the amp to Joe's place so we could switch from Jan Phillips to
Sovtek 6922s. This was no simple task. In order to rebias the Galaxy, one
must open it up, replace whatever tubes one wishes to replace, turn it on
and warm it up until everything stabilizes, carefully measure voltages
across certain resistors via a voltmeter, and adjust the bias by turning
screws a little bit at a time.
While there is no way to adjust the bias of driver tubes
(6922s), replacing them affects the bias of the EL84s. Adjusting the bias
of the EL84s in turn slightly affects the overall bias of the quadrant,
necessitating rebalancing of the eight 6AS76 triode power tubes. These
power tubes are biased in pairs, with the biasing of one pair affecting
the biasing of the total quadrant. For utmost accuracy, since rebiasing
each tube affects the bias of all others tubes in the quadrant, those who
wish to end up with optimal biasing will wish to allow the tubes to
restabilize after initial adjustment and then repeat the process, starting
with the EL84s. This process, which takes a decent amount of time, is not
explained in the literature which accompanies the amp.
Some audiophiles and engineers may
enjoy all this fiddling with the tubes and bias. For me, the simplicity of rebiasing the Bruce Moore amps,
accomplished by turning external surface mount screws while consulting a
built-in meter mounted in full view on the chassis, makes the Kora biasing
process seem positively medieval. It's certainly not a process that those
with shaky hands, poor eyesight, or fears of accidental electrocution
would wish to engage in. P.S. - I fear electrocution.
Kora writes the following in its manual [bold and
italics theirs]: “The tubes supplied… have been tested, matched and biased
in our workshops. They are guaranteed for 900 days after purchase and
under proper usage. They do not need re-biasing except
in the unlikely case that the tubes need to be changed for some reason.
Well, this does happen! If this is the case, please contact
your dealer who
will be happy to supply and re-bias new tubes for you…” To which I would
add a word to the wise: Purchase this amp from a local dealer, rather than
by mail order or on the web, if you want to avoid possibly undertaking the
biasing process yourself.
The voltage in my apartment changes from morning to
night. Although voltage to most of my components is stabilized via the
P600 Power Plant, I plug my amp directly into the wall via an Ultimate
Outlet. Thus the bias of tubes changes throughout the day (along with the
normal changes that occur as the tubes age), as well as between weekdays
and weekend. According to Joe Cutrufelli, this small change in bias
affects the “flavor” of the presentation, but does not dramatically alter
the sonic signature.
Apples and Oranges
In most reviews I have read, reviewers simply list a
host of interconnects, power cords, speakers and the like, that they tried with
the component under consideration. Other than saying that such and such
amp sounded much better with Brand X interconnect than with Brand Y, and
reminding readers that “component matching” is essential, they rarely
discuss how differences in component configurations affect their ultimate
In a perfect world, I would have used the same model
preamp and interconnects in balanced and unbalanced modes. This, however,
was not possible. Rather, my evaluations in unbalanced mode employed the
Bruce Moore Companion III preamp connected to the Kora via RCA-terminated
Nordost Valhalla interconnects, while balanced mode evaluation called upon
the Atma-Sphere MLS-1 preamp connected via balanced Acoustic Zen Silver
The Atma-Sphere is a more expensive unit than the Bruce
Moore, but the Valhallas cost far more than the Acoustic Zens. How
possible is it to determine how these differences in configuration
affected the sound I heard? Without engaging in hours upon hours of
testing, all I can say for certain is that the expensive Atma-Sphere
preamp is highly rated, quite transparent, and very neutral. The Bruce
Moore, while different in price and design, is a fine unit; in its Deluxe
Version, long overdue, it will hopefully give the Atma-Sphere a run for
its money. As for the interconnects, in a brief A/B comparison of Acoustic
Zen Silver Reference and Nordost Valhalla conducted at Joe's, I felt that
while the Acoustic Zens lacked the body and low extension of the Nordosts,
they were quite transparent and open on top. Putting this all together, I
feel relatively confident that my conclusions about this amp - certainly
about its top extension - are valid.
Liquid, liquid, liquid. A beautiful, unimpeded flow of
sound, an ease of production, and a marvelous sense of transparency are
the features of this amp that struck me the most. Whether listening in
unbalanced or balanced mode, I experienced an unimpeded flow of sound,
bordering on the elegant.
Listening to music through the Kora Galaxy Reference is
a lovely experience. It doesn't jolt you, startle you, grab you by
whatever; sound naturally flows through the room, like water in a gentle
This does not mean that detail is lacking. A case in
point is Matthias Goerne's brilliant, albeit artistically controversial
recording of Schubert's great song cycle, Die Schöne Müllerin.
I have commented elsewhere that Universal has done a lousy job of
capturing the elemental combination of Goerne's voice and Eric Schneider's
modern piano. Goerne sounds almost as if he's in a tunnel, with an
unnaturally huge amount of reverberation around his voice that lends it an
artificially metallic, somewhat harsh sheen and obscures detail. The disc
offers anything but the acoustic and beauty of tone I encountered when I
heard Matthias Goerne perform live on three different occasions.
The Kora/Atma-Sphere combination certainly doesn't hide
this sonic defect; rather, the recording's deficiencies struck me as even
more disturbing than when I listened to the disc using the Companion III
preamp equipped with shunt attenuators and less than top-of-the-line
resistors and capacitors.
What the Kora Galaxy Reference offers in spades is
midrange. The center of Goerne's voice or the piano's strings; the
beautiful warm sonority of strings, winds and percussion on the superb
Reference Recordings disc of Rachmaninoff's Symphonic Dances; the
beautiful liquidity of soprano Arleen Auger's voice on her great Delos
Love Songs recital, all come through beautifully.
On the other hand, what I missed the most was sheer
weight and sense of instruments - a visceral sense of bulk to the sound
- and extension at frequency extremes. The lack of weight, of course, is
in part a result of an amp rated at only 50W, which provides less heft,
slam, and forte swell than one rated at 100W. But the issue of frequency
extremes is another matter entirely.
A case in point. One of my favorite “pop” cuts for
evaluation purposes is “Blues No More” from Terry Evans' JVC-XRCD,
Puttin' It Down. I am accustomed to
hearing huge contrasts in timbre between snare drums, electric guitar,
trombone, cymbals, and Evans' voice. The cymbals are soft in the
beginning, but when the drums are thwacked hard, I expect to sit up and
taking notice. And when Ry Cooder begins to twang his guitar, there's a
characteristic spice to the sound that I continually look forward to.
Such was not my experience with the Kora Galaxy
Reference. Its presentation was quite mellow. The highs did not shine;
neither did the bass pound. There was a uniformity to the sound, ideal for
listening without intruding on the space of one's partner or neighbors,
but certainly farther from the real thing than I'm used to hearing. My
Bruce Moore amp may fatten the sound a bit, but the Kora Galaxy errs in
the opposite direction.
I had a similar listening experience playing mezzo Susan
Graham's recent Erato release of French operetta arias, or the Grammy and
Golden Ear award winning Sony recording of Brahms and Stravinsky Violin
Concertos by Hilary Hahn. The lack of bass slam or deep extension was a
minor issue; far more crucial was the lack of a leading edge to the tone,
and an overall greyness to the sound. Even as I write this, with the Bruce
Moore equipment reinstalled, I return to Graham's recording and play the
first cut, Moïses Simons' “C'est ça la vie, c'est ça l'amour” from Toi
c'est moi and hear a range of
instrumental color, a luscious roundness, and a life to the voice that are
lacking through the Galaxy Reference. The midrange at which the Galaxy
Reference excels is certainly there, albeit presented with less liquidity
and transparency. But this is a tradeoff that I am glad to accept.
My experience would have been quite different if I had
bright speakers, bright interconnects or speaker cables or power cables,
or digital equipment that lent a harsh, digital edge to the sound. Some
horn speakers and Lowthers frequently employed with triode equipment might
thus prove a superior match with the Galaxy Reference, providing they can
handle 50W of power. But for this music lover, who has gone to great
lengths to assemble a system that makes it a pleasure to engage in
extended, concentrated listening without fatigue, the Galaxy Reference did
not prove an ideal amplifier.
At a recent Master Class I attended, the great soprano
Elly Ameling, now retired, attempted to explain the nuances of
interpreting French art song by referring to the difference between French
sadness and German sadness. I cannot pretend to accurately paraphrase her
comments, but she implied something to the effect that the sadness one
encounters in Debussy and Fauré is far more contained, far less of an open
outpouring of pain and angst, than what one encounters in Schubert and
Such an analogy might equally apply to the Kora Galaxy
Reference. The Kora is by all means a refined product, capable of
producing an extremely elegant, flowing line. It doesn't confront you with
its feelings, or knock you over with sentiment. Cultured, poised, perhaps
a bit guarded of its secrets, it's the antithesis of a walk down the
streets of New York or an evening with The Boss. With the right
equipment, the right music, or in the right listening situation, the Kora
should prove a fine match.