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A Golden Duo
Separate pre and power amplifier combinations
cost considerably more than integrated amplifiers, but promise more
universal application possibilities and better sound. All the more
so when a good phono stage is offered. For our test we have chosen
a very interesting combination which is far removed from the Hi-Fi
mainstream.
Canadian Heavy Weights
Assembled Prominence: The promising Bryston pre and power amplifier
combination fought honorably in the SOUND & vision listening
room for "sound" high accomplishments. It was musically
inspired by its majesty, the SME-30 record player, and its queen,
a Benz Ruby cartridge...
The Bryston products which were tested, the BP-25 preamplifier
and the 4B-ST power-amplifier, come from Canada. A surprisingly
small, remote controllable, preamplifier and a classically appearing,
strong, power amplifier, which despite its 2x250 watts does not
exhibit monstrous measurements, but retains handsome and compact
good looks. The BP-25 preamplifier is just 4.5 cm (1.75 in) high
and despite that offers more than enough applications - In addition
to the four high-level inputs, and the tape monitor, there are two
balanced XLR inputs. The output section is also equipped with two
unbalanced (RCA) outputs and one balanced XLR output, thus covering
all possible requirements including bi-amping. The cabinet of the
BP-25 makes an outstandingly rugged impression, and the operation
of the component, thanks to the handy knobs and the sensible control
layout, is really fun. In addition there is a remote control for
volume adjustment and for absolute phase reversal. A special technical
feature is the separate enclosure for the power transformer, whereas
filtering and regulation takes place within the main housing. This
is only one of the many measures which help the BP-25 to be as noise
free as possible. Also the channel and the input cross talk has
obviously been minimized. The results they can be proud of: With
107 dB signal-to noise ratio the diminutive Canadian achieves a
world record, and input cross talk - common more often than one
would believe - there is absolutely not even a trace. Bravo! The
BP-25 offers as an option phono inputs for just MM or for both MM
and for MC cartridge input (selectable on the front panel). We had
the latter version available which exhibits a superb signal-to-noise
ratio (85 dB, A rated, for both the MM and MC resp. 5 mV/0.5 mV).
The MM input is very precisely equalized (+0.13/-0.06 dB) and has
a useful input sensitivity of 5 mV, which however is too low for
medium and high output MC cartridges. The MC input with 0.2 mV sensitivity
is also suitable for very low output cartridges. The equalization
is not completely ideal here, it exhibits a minimal high-frequency
roll-off of about 1 dB at 20 kHz (0.3 dB at 10 kHz, 25 ohm source
impedance). The MC section uses step-up transformers, which are
optimized for a very low system impedance of about 5 ohms (for example
Ortofon cartridges). With high impedance MC cartridges (around 25
ohms) a small amount of high-frequency roll-off may occur.
Rugged Power Package
The 4B-ST power amplifier, already available for many years, and
again and again improved, has almost become a legend. Originally
developed for professional applications it quickly developed a reputation
for its harmonious sound, which is due, among other attributes,
to its harmonically descending extraordinarily low distortion (0.0012%
at 1 W), in which the pleasant sounding K2's dominate. The "quad-complimentary"
circuit configuration which consists of four specially selected
bipolar transistor pairs, each pair with its own driver transistor,
must be responsible for this. But also stability and bass control
must be >given high marks for this power amplifier. A dual mono
power supply with two gigantic toroidal transformers and four electrolytic
filter capacitors (200,000 mfd per channel!) create "lots of
steam" and enable the 4B-ST to provide ultra-fast, exceptionally
tight bass response. Also the damping factor is correspondingly
high (>400 at 8 ohms/i kHz). It is preferable to use the balanced
line to hook up to the BP-25, while the loudspeaker terminals accept
either bare cables, spade lugs, or banana plugs. A special feature
allows the 4B-ST to be bridged which then offers the immense output
of 800 watts at 8 ohms. But even in stereo operation loudspeakers
have nothing to lose, since we measure continuous output of 270
respectively 380 watts at 8/4 ohms, and peak output an ample 470
respectively 630 watts at 4/2 ohms. It is gratifying to note that
also here the signal-to-noise ratio of 90 dB, respectively 98 dB
at 1 watt, is very high. The Bryston combination, so to speak, is
already prepared for the high resolution digital era
 Hook-Up
Marvel:
The Bryston preamplifier provides balanced inputs as well as outputs.
Also the power amplifier is preferably connected in this professional
manner. And it is befitting that the Canadian manufacturer provides
a 20 year warranty which further enhances the all around favorable
impression of these components.
Audiophile Rendezvous
In the SOUND & vision listening room the pre and power amplifier
combination was allowed to prove what it had soundwise "on
the bail." For the adequate judgement of the phono stages the
Egli Fischer Firm kindly loaned us an SME-30 turntable with an SME-V
tonearm Phono cartridges used were a Shure Ultra 500 (MM), an Ortofon
Rohmann (MC), as well as a Benz Ruby and the high output version
of the Glider. Piegas PlO served as reference loudspeakers as well
as the elegant compact Guarneri box speakers from Sonus Faber. The
combination CD transport/digital processor CM3000AC/ PreDA3000 from
T & A, as well as the Jade/DSP Generation V from Theta served
as digital sources.
MM Sound Not Antiquated by a Long Shot
Those who believe that MM phono cartridges can only attain a nostalgic
round record reproduction without notably high frequency response
should listen sometime to the MM input stage of the Bryston preamplifier.
It achieves fascinating listenability with brilliant highs and precise
instrument location. Human voices are prominently articulated and
yet sound very natural, and in addition one experiences the room
acoustic reproduction as being just right. In a class by itself
is the tight, dynamic bass reproduction, which immensely benefits
music heavy with low frequencies. Its terse and precise pace (not
to be confused with the artificial grandstanding of many cheap phono
stages) also predisposes this MM phono stage for jazz and pop music
where it truly conveys the spirit of this music by virtue of its
vigorous tonal characteristics. But also classical music lovers
will value the exceptional pace which is by no means lacking in
refinement, and this all the more so because no annoying background
noises hinder the enjoyment of the music.
MC Sound: The Zenith of Emotion
The Bryston MC phono stage reproduced the Benz Ruby cartridge with
great precision but one did miss a bit of resolution with this prime
cartridge. The integrated step-up transformers dealt much better
with the Ortofon Rohmann (impedance 6 ohms) cartridge. The treble
response was now very well balanced, and finely tuned, with good
bass and lean, yet well voiced elementary tone fundamentals. The
acoustic environment reproduction was deemed to be excellent, the
dynamics, which came especially to the forefront because of the
exemplary freedom from distortion, as very good.
CD Sound: Nothing Finer
The Bryston pre and power amplifier combination demonstrated peak
performance when connected to the high quality digital sources used
for this report. With classical music the Bryston combination impressed
with full-bodied rounded reproduction, which accords voices a wonderful,
almost tube-like, timbre. We had not expected such beautiful sound
from a professional power amplifier right off the bat! This must
be appreciated all the more because everything that's bloated and
not clearly defined is foreign to the two "Canadians."
The reproduction precision is without a doubt superb, and also the
key area of treble resolution and spatial openness, despite the
distinct aesthetic sound, will leave no one disappointed. The Bryston
combination harmonized splendidly with the brilliant and analytical
Piega loudspeakers which are propelled to sensational bass performance
with exemplary delineation and burst accuracy by the 300 watt power
amplifier. But even the small box speakers from Sonus Faber profited
from the close-to-reference low tone definition. Acoustic jazz has
the appropriate swing and low notes, while rock and roll are reproduced
effortlessly with true-to-life volume, without hardening the sound
picture or softening the bass.
Bryston BP-25 and 4B-ST test Summary
The surprise in the test: Starting with CD's this pre and power
amplifier combination sounds exceptionally beautiful, and always
endows music with a subtle, golden, brilliance. Transparency and
spatial openness are simultaneously excellent, and bass reproduction
is even suspiciously reference-like. The MM phono input operates
noise-free brilliantly, and dynamically, and for the MC phono input
one must first find a suitable, low resistance MC cartridge. If
one looks at the superb workmanship and the perfected practical
operation usefulness one easily comes to the conclusion that these
are true "best-buy" components. For a North American power
amplifier with this sound and output criterion one normally pays
at least 6000 (Swiss) Francs (about US $4320) and more. Since in
addition one receives a 20 year warranty, a "buy" recommendation
is made even easier.
We invite you to experience the Bryston SST2 Series amplifiers
20 Year Warranty - A Generation of Music
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