 Authorized
RePrint of
HiFi Media
April 2004,
Saucer-full
of Secrets
At last year’s Audio/Video Show in Zagreb
one of the rooms that won unreserved admiration belonged to Austrian
firm AviTech, where PMC speakers in combination with Bryston Amplification
were exhibited. During the show they were looking for a local
distribution/dealer and when they found one we decided to test
some of their components.
We took PMC model OB 1 speakers, Bryston integrated
amplifier B 60 (used as a preamp) and Bryston 4B SST amplifier.
This system, due to the limited time we had for listening was
auditioned only in our own listening room. The original idea was
to use these components in combination with other components,
and review each of these components separately. But due to the
lack of time, we were forced to limit our review to only this
system as specified. We used the Exposre 3010 CD player as a source,
WireWorld Polaris and Exquinox cables and Eclipse speakers.
 PMC
OB 1
This speaker is a three-way transmission line (TL) design. The
high frequency drive unit is 27mm Silk soft dome ferrofluid cooled.
The mid-range is a doped, 75mm Fabric soft dome with a separate
acoustical enclosure to prevent eventual negative effects from
the massive170mm low frequency unit. The crossover is Linkwitz
Riley (24 dB/oct ) made of hand selected and matched components
that are first tested before they are soldered by hand using silver
loaded solder. According to PMC Designers, extra thick copper
tracks are laid onto the board to ensure high current capabilities
and reduce signal loss guarantying superlative performance. Sensitivity
is very solid at 87db/W and as it has three pairs of Binding posts
it is possible to try-amp or try-wire the system.
The cabinet is constructed using special panels
called “Medite”. Inside the speaker there is a 3.3m
long transmission line which is braced by the internal labyrinth
braces. This design, perfected by PMC designers with great success,
is precisely tuned and damped with foam to absorb unwanted vibration.
The secret of good TL design is actually in absorption of unwanted
vibrations, but with out effecting the flow of the air. This design
in theory has a lot of advantages over Bass Reflex design but
is used much less because of a need for very precise tuning and
a need for an adequate enclosure and because the penalty for an
unsuccessful implementation results in a very bad sound.
 Bryston
4B SST
Bryston 4B is a legendary amplifier which has been successfully
used in home or studio application, for almost 30 years, and during
that period has been changed and improved many times and stayed
very well built, and very powerful in full dual mono configuration.
From every aspect, the most changes and improvements until today
are implemented in the newest SST version.
The power supply is fully independent, using
a high power transformer for each channel and employing multiple
filter capacitors per channel, rather than single pairs of larger
filter cans, improving high frequency response and reducing overall
losses in the supply. Only the finest selected components are
used; metal-film resistors, polystyrene capacitors and hand matched
transistors, top quality transformers. The chips are placed far
away from the vital parts because of unwanted effects, and internal
connection is implemented with very low impedance to reduce the
distortion. New proprietary grounding protocol and “Quad-Complementary”
output section technology, in which Bryston believes and the measurements
prove, eliminates higher harmonic distortion and provides configuration
close to class “A” amplifiers, and in some other parameters
exceeds them- the very reason for SST creation. Output transistors
are by Motorola and Toshiba, and as the amplifier is capable of
drawing a large amount of power, it has a few mechanisms for protection
which are needed to be able to compete on the professional market
and a soft start circuit on power up. The chassis, as expected,
is massive, very good looking and the quality is very high. There
is only an on/off switch on the front and various types of connectors
and speaker binding posts. In this test I used only RCA connectors.
The quality is at the expected level, keeping in mind that Bryston
is providing 20 years of transferable warranty.
Bryston B 60
In this test the B-60 was used as a preamplifier and connected
to its preamplifier-out connectors. Its specifications are like
4B SST specifications, with certainly much less power. According
to the importer, the characteristics of the preamplifier section
are similar to model BP-25 which is an excellent partner to the
4B SST. I would have preferred to have the BP-25 for this test,
rather than the preamplifier section from an Integrated Amplifier.
But, what you see is what you get. The B-60 is solidly made with
selected parts, discrete technology on many signals, gold plated
connectors on 4 inputs, additional tape-loop, headphone output,
and quality steel housing. Certainly, it also has a 20 year warranty.
The Sound
I started testing the sonic qualities with classical music and
big orchestras so that I could immediately confirm or change my
expectation of the system, which was based on the specifications
or a few minor and short listening sessions of the equipment by
the same manufacturer. Although Bryston is bursting with power,
this power is not used to feed hungry membranes of speakers or
to impress the listener with access of power. Its power is finely
distributed to moving and controlling various drive units. This
handling authority of 4B SST is very well suited for PMC. The
instant movements of its membranes, and delicate handling, does
not allow the system to become undisciplined in any part of the
specter, resulting in excellent integration of all driving units,
without any bad effects or any distortion. In this configuration,
the system sounds lively, exhilarating and very involving. The
high frequencies, using high quality drivers, are excellent and
very detailed. The sound is exceptionally natural and finely woven
with the most delicate details throughout the spectrum, with some
detected sweetness in some parts of the spectrum.
So, hats off to the system and it’s most
important and vital qualities, which without any reserve, meet
the highest criteria. At the end of this part of the dissection
of the sonic characteristics of the system it should be noted
that the midrange is clear, transparent, and also slightly sweet
in a very positive way, and gently interacting with the listener
and with the rest of the spectrum. It presented a very wide, deep
and focused soundstage, and the listener can, without any effort,
clearly feel the ambiance of the recording events in both large
venues as well as in studio recordings. Furthermore, it handles
enormous dynamic demands with ease and clarity.
In the background of this dynamic and powerful
sound there is excellent “air” and “space”
and it is capable of realistically reproducing a live event. Not
a single detail was missed in the material that I am fully familiar
with. During the listening of big orchestral recordings, the width
of the soundstage was almost unlimited, and as we listened more,
the performers were getting closer to the listening position.
I also had this feeling listening to rock music, which the system
handled easily. In those moments, I had a feeling that the system
was working at a half of its power, without any objections to
the quality of the sound. Smaller ensembles and soloists were
reproduced accurately, although there was some light emptiness
in some parts of the sax solos. I felt that the sound of the sax
got spread in a large space, and moved from its dedicated sweet
spot. After the sax solo, and as soon as other instruments joined
in, the sound returned to qualities described above. Interestingly,
this is experienced only on studio recordings, while in live recordings
this small feeling of emptiness was filled by ambience noise and
the noise of never fully quiet spectators.
At the end of the test I was back to listening
to classical music, which is a natural choice for this system.
Masses of sound, space, powerful and dynamic bursts, and unlimited
amount of space and air are the most appropriate descriptions
of this system at its best. Ditto for reproducing the most difficult
material. Interestingly, both, the soft passages on various vocal
recordings, and the very different outbursts in dynamic and explosive
recordings of classical music are equally well reproduced. It
was a real surprise to listen to voice of Jimmy Smith after the
performances of large and difficult musical pieces. For a moment
I had the impression that I was listening to another system. The
ability and experience of designers, in designing and perfecting
the system components of such a high quality, must be highlighted
again. Let us not forget that this Amplifier is only the incarnation
of a legendary design with the quality of the sound and construction
that has been received with great enthusiasm by audiophiles for
many years. Also the Pre Amp section that we used was en excellent
partner to the Amplifier section.
PMC’s OB1 design
was based on their expertise and experience in designing and perfecting
their other models for professional and home use. The sound of
the system is defined not only by its Audiophile Qualities, but
also by its effortless simplicity and lack of pretension. This
reviewer was totally impressed. The system’s characteristics
and Audiophile Qualities, and its lack of pretension warranted
the recommendation by themselves. This was proven to Croatian
Audiophiles at this show. And, certainly, not for the last time.
We invite you to experience the Bryston SST2 Series amplifiers
20 Year Warranty - A Generation of Music
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