Squared amplifiers sound well rounded in musical terms
The 7 series of amplifiers has been in Bryston’s line-up
for about 16 years beginning with the 7B, followed
by the 7BSST and now replaced by the 7B SST Squared models.
Though there have been changes as technology advanced over
the years, the new Squared 7B monoblocks hold Bryston’s
latest and highly evolved audio technology. Many design elements
have been improved upon, critical parts have been changed
and even the faceplate has been refined.
While the amps still maintain the traditional Bryston look,
I noticed that the faceplate is now beveled, giving the amps
more pleasing visual appeal. The front, centered on/off switch
is now a mechanical device replacing the earlier relays.
It and the indicator light (red for standby, green for operation)
are still flush mounted. On the units’ rear, there
are provisions for balanced and single-ended connections,
a master AC toggle, the fuse, a ground lift switch and a
12-volt trigger switch. The binding posts have been improved
and can accommodate spades or banana plugs.
Each amp measures 19’ long, 5.25” high, and
12.5” deep and weighs about 50 pounds. The amps are
available in silver and black finishes.
I used a pair of Gershman X1 with matching (passive) subs
to burn in the amps. I used my in-house preamplifier, the
Weytech Lab Ruby model (a finished prototype), a Pioneer
Elite transport and an AA DAC and clock made up the balance
of the auditioning system. Two sets of cables — from
BISAudio and Ultraliink Argentum — I had previously
reviewed served as interconnects, speaker and AC cables.
As Bryston connects all amplifiers for 100 hours before
delivering them to their destination, the after-burning–in
[sic] can be regarded as the final step to achieve their
best performance. Thus, I played them for hours, before I
sat down to some serious listening. I’d like to mention
here that, to my surprise, they didn’t sound cold or
edgy, even before the necessary burning in period. However,
they did begin to show their sonic disposition after but
a few hours of operation and I noticed steady improvements
over the next few hours. At the beginning of the listening
sessions, they sounded surprisingly smooth— as in mellifluous — but
didn’t reach the operating stage that provides a good
perception of the music’s harmonic structure. Nevertheless,
imaging and instruments’ tonal characteristics were
discernible. A few more hours later, I began to hear harmonics,
better focused imagery and improved tonal balance.
Another 40 hours later, the amps were sufficiently “burnt” and
ready for the final auditions. For these I used, first the
Gershman and later the Ethera Vitae speakers (my preference).
You may have seen in some of my other reviews that I am
a stickler when it comes to harmonics, and to ascertain an
amp’s ability to reproduce them, I always use a few
piano recordings. They include music played on Yamaha, Steinway,
Baldwin and Boesendorfer grands.
I used my Jazz CDs on the Concord label with Gene Harris
on a Steinway, Dave Bruebeck on a Baldwin and Oscar Peterson
on a Boesendorfer. On the Three Blind Mice label, the sound
of a Yamaha grand is clear. I chose these recordings, not
only for their production quality, but also because small
ensembles (quartets, trios, etc.) perform the music. As each
piano has a unique sonic signature with which I am familiar,
I can focus my attention on their characteristics. Consequently,
judging the amps’ ability to reveal the personality
of the pianos is not very difficult.
The 7Bs did not disappoint. They easily elucidated the personality
of the pianos and that affirms their ability to recreate
likely up to ten harmonics. Most of the piano music is in
the critical midrange area from about 160Hz to1300Hz and
the amps simply did what they are supposed to do. As all
great amplifier designs, the 7Bs didn’t accentuate
the midrange region, nor did they conceal a single note,
thereby making it possible to listen into the music and discern
inner detail and micro dynamics.
Though midrange is likely the most dominant segment of music,
it is a small part for the amplifier to deal with. The section
above the midrange — that is all the upper and top
frequencies from about 2600Hz to 20kHz — is important,
since it must handle some fundamentals produced by instruments,
as well as loads of harmonics. This is where the new 7Bs
literally shine — not to be confused with glare or
sparkle with brightness. The entire upper midrange is smooth,
seems exquisitely balanced with the midrange and finishes
with finesse and sonic refinement at ultra-highs. The 7Bs’ achievement
in this frequency segment is likely the reason why the important
harmonics are reproduced appropriately. This and the amps’ tonal
balance makes listening to female and male vocals a joy.
With large orchestral works, first and second violins, violas
and cellos come to life, but do not have an annoying strident
attribute, often found in solid-state amplifiers.
And then there is the bass. The 7B series of amps always
had awesome bass. The sheer power of these beasts combined
with dynamic firmness and easily made even inefficient loudspeakers
render the most satisfying bottom octaves. The strength of
the earlier 7Bs was resolution across the audible spectrum — a
characteristic that sometimes resulted in a bit of hardness
at top frequencies. However, it assisted the bottom end of
all speakers that reach into the pedal-note frequencies.
I remember bi-amping loudspeakers with the 7BSSTs to maximize
bass performance that many other amps couldn’t achieve
(my friend and ex-partner Sol can attest to this as he drives
his subs with 7BSSTs in a superb audio set-up).
Having said this, it’s time to talk about the new
7B Squared. The bass part of these amps has become a little
softer in temper; not as resolute as the previous model,
but more organic in sound quality. Listening to some Jimmy
Smith B3 recording, I found that pedal notes are a bit more
harmonious, a little more pleasing to the old ears. My Fidelo
recording Sept Patroles Du Christ features a pipe organ with
a 16Hz note and is a great test for any system. I found that
the 7Bs handled the note down to around 28Hz — the
point at which the auditioning loudspeakers simply quit.
Nevertheless, the amplifiers’ organic attributes made
the organ sound realistic, reaching in the bass area without
hesitation and with plenty authority. The aforementioned
CD also has female vocals along with the bass, and reproducing
both together requires an amplifier that provides body and
texture for the bottom end, as well as a great deal of finesse
for the midrange. The 7B Squared passed this test easily.
I had a clear impression of the vocals, not dominated at
all by the music’s rich body in the bass area. All
this in the appropriate spaces on the sound stage — centre
stage up high for the voice, rear stage slightly left for
the organ bass.
All in all, the new amplifiers offer a more natural flow
of the music and handle all frequency segments with equal
strength, which at the end sounds more realistic when live
music is used as a yardstick.
Another realist element is the 7Bs ability to set up a mean
sound stage. They help making the system disappear and provide
out-of-the-box imagery, behind and well above the confines
of the loudspeakers. In fact, the sound-stage height, focus
on instruments and voices, front-to-back layering and spatial
elements are the amplifiers’ most remarkable features,
matching the 28B SST’s performance.
My memory banks fail when it comes to names, model numbers,
and a whole lot of other things, but, surprisingly, I remember
sound quite well. Thus, I remember the sound of earlier 7Bs
and I can attest to the sonic changes and admirable improvements
of the new 7B SST Squared.
These amplifiers are the best Bryston ever made since the
inception of the 7B series a couple of decades ago. In my
opinion, the only amps that will outperform the new 7BSST
Squared units are the 28B monoblocks I have reviewed about
three years ago (review is posted in out archive section).
Both sets of amplifiers have delightful sonic characteristics
that cannot be categorized easily. Both designs boast what
solid state is all about — loads of kinetic energy,
great dynamics, speed and control. However in addition to
those elements, these amplifiers have a warm blossoming quality
that is customarily found in (expensive) tube gear. As the
7B Squared amplifiers offer a bit of both, they may be the
solution to achieve a high degree of musicality with any
loudspeakers rated under 90dB efficiency. They will, however,
sound great with any loudspeakers under the sun. They are
still offered at a very reasonable price, which, in my opinion
is not indicative of their performance in the high-end category
of the audio industry. They may well be the least expensive
high-end monoblocks on the market.
If you wish to get the most out of the amplifiers, it is
wise to use good speaker cables and interconnects. A super
preamp and good source components are mandatory. Before you
spend your bucks, I suggest an audition at your Bryston dealership.
|Bryston 7B SST Squared (2) Monoblock Amplifiers
677 NEAL DRIVE
PHONE: 705 742-5325
|$4,195.00 each (US & CDN)
Each amplifier delivers 600 watts
into an 8 ohm load and 900 watts into 4 ohms. Gain is selectable
with either 2.3 or 4.6 volts @ 8ohms; input impedance s 50Kohms
single ended, 20Kohms balanced; distortion — IM and THD
is quoted as <0.005% at 600 watts and 0.007% at 900 watts;
signal to noise ratio is >110dB from 20Hz to20kHz (superb,
and the reason for the very low noise floor); slew rate is 120
volts/ms; bandwidth is < 1Hz to over 100kHz.
When idle, the amps consume 215 watts each; when in full operation, they’ll
gobble up to 1284 watts.
These amplifiers boast a lot of design and component changes, beginning with
new power supply transformers that feature very high energy storage. This eliminates
narrow peaks of up to 50 amp current, thereby eliminating voltage dropouts caused
by the continuous recharging of filter capacitors by the transformer. The design
differs from the standard transformers used by most manufacturers and came about
by adopting some of the technology used in the Torus power-line conditioner (for
these amps, you needn’t use a line conditioner). It recharges the filter
capacitors directly from its own energy storage capacity, and then takes up the
energy from the wall socket over the full 60 Hz waveform. This method optimizes
the amplifiers’ performance regarding focus, dynamics and imaging.
Furthermore, new and improved capacitors were employed. Bryston’s research
department discovered new input and feedback capacitors that will lower total
harmonic distortion and improve the sound quality across the upper frequency
range from 20kHz to 60kHz. The caps are now used in all Bryston amps. However,
only the 28B SST, the 14B SST and the 7B SST — the most powerful units — have
the transformer changes.
Bryston checks each amplifier’s specifications, and I noticed that the
amps under review actually delivered 625 watts before clipping, the noise floor
was 6dB lower than the spec sheet stated and THD was on average 20% better than
According to Bryston’s James Tanner, the company design criterion was to “get
the first watt to the last watt” at equivalent quality. This translates
to the amplifiers’ ability to maintain an ideal power curve through the
first and last watt (most solid state amps work best at one/third of their power
rating). Both monoblocks are full balanced, whereby positive and negative terminals
are amplified. Those who are interested can contact Bryston for a white paper,
which describes the technical details.