BP-173 Cubed Series Preamplifier
In August 2017 Bryston announced its new BP-173 preamplifier, the first significant revision of the model since its introduction in 2012. Yet, even more significant is that this was also the first-ever Bryston preamplifier to get “Cubed”. What’s Cubed? Bryston launched its Cubed Series amplifiers back in January 2016 to accolades. Speaking from hands-on experience, my main amplifier is a Bryston 4B3. The Cubed Series delivered, dare I say, a revolutionary performance improvement over previous Bryston amplifier generations. At the heart of the Cubed update is the Salomie input-stage circuit, named after its late designer Dr. Ioan Alexandru Salomie; so innovative that Bryston has it patented. Given the broad recognition and success of the Cubed amplifiers, I was in great expectation of what the Salomie circuit would deliver within the BP-173 preamplifier ($3,995 US).
DESIGN & FEATURES
In addition to the new Salomie input stage the BP-173 has gained two pairs of balanced (XLR) inputs, one of which is configurable as either variable or fixed. And, Bryston developed a new digitally controlled analog balanced volume control for the BP-173. The rear panel is arranged differently to accommodate the new XLR plugs but still remains simple, clean and functional. Form factor of the BP-173 remains unchanged from its predecessor but keen eyes will notice the new Cubed faceplate with Bryston’s thin-line logo. Black remains brushed but the silver gets the new Cube Series micro-bead blasted finish for a softer and more sophisticated appearance. The front face plate is 1/4”solid aluminum with all-aluminum vibration-resistant casework. The chassis is perched on four professionalstyle rubber feet and all connectors are sturdy professional-grade. Build, fit and finish is typical Bryston – that is to say top notch.
When it comes to standard options, the BP173 preamplifier comes with a few choices. Finish is black or silver; a 17-inch or 19-inch faceplate; an optional integrated 96 kHz/24bit DAC ($750 US) with 2 coax and 2 optical inputs; optional MM phono stage ($750 US) and finally, an optional Bryston BR-2 remote control ($375 US). Oh, I almost forgot, you also have the option of standard green or optional blue running lights.
The Bryston BP-173 offers a bounty of connections including: 2 balanced (XLR), 4 single ended (RCA) inputs; 2 balanced (XLR) outputs, plus 1 RCA preamp out and 1 RCA fixed output; IR remote-control sensor; remote in/out pin connectors and; an RS232 jack. Detailed specifications can be found at www.bryston.com but let me share a few highlights with you: the BP-173 is rated with a THD of < 0.0025% (with IMD
0.0003%) and noise of -102 dB (RCA) and -108 dB (XLR), as well, an output of up to 15V (RCA)/30V(XLR). All Bryston components come well burned-in from the factory, part of their QC testing, yet I put about 300 hours on the BP-173 before
any formal evaluations. All my listening was done on my reference system: a Bryston BP-26 preamp and 4B3 amplifier, MOON by Simaudio 280D DAC/player, Rega Apollo CDP and VPI Scout 1.1 turntable. Loudspeakers were my Audio Physic Scorpio 25+ and Focal Electra 1008Be, and cabling was courtesy of Nordost Heimdall 2 / Tyr 2, with QB8 power distribution.
The track, “A La Vericale”, from David Sanborn’s album Time and the River is a complex interaction of instruments and if not properly handled sounds congealed. Listening to this track through the BP-173, I was fascinated by the crystalline purity that the cymbals possessed. There was a heightened level of delicacy and complexity unlike anything I’ve previously experienced. The shimmer of the cymbals was handled with wonderful precision, allowing me to follow the strikes and easily hear their full decay amidst the other instruments. My suspicion is that the lower distortion level might be what was allowing me to perceive greater clarity, detail and delicacy in the upper-most frequencies. This sense of purity and the associated benefits also extended to the shakers, which were superbly rendered with focus, texture and timbre that was also to a heightened level. Percussion had an incredible touch-and-feel quality, with a most tangible snap to the skins, natural timbre and startling speed. The BP-173 also exhibited an iron-grip over the lowest notes lending to greater bass texture.
As I listened, I was struck by the ability of the BP-173 to provide focus and separation amongst the elements within the soundstage. Elements were carved out in three dimensions, holographic within the stage. In comparison, my Bryston BP26 preamplifier sounded diffuse, with an apparent haze, which I state with some reservation as those adjectives are not ones I would normally use for the BP-26; however, in comparison to the BP-173 that’s what it was. This greater focus of the BP173 resulted in a perception of elements within the soundstage being more compact and denser. Bass was noticeably tighter and more articulate with the BP-173, which revealed the BP-26 to have a somewhat pronounced and slightly forceful upper bass. Generously wide, deep and high soundstages were customary with the BP-173. Yet what was most interesting was that the furthest and faintest elements within the soundstage could more easily heard and with more nuance and presence, something I’d attribute to the ultra-low noise and distortion of the Salomie input-stage.
Moving to female vocals, I listened to Juno award winner Diana Panton’s album If the Moon Turns Green and the track “Quiet Night Of Quiet Stars”. Here the BP-173 again spoke with clarity, focus, definition and astonishing low-level detail. The soundstage presented seemed to begin just behind the front plane of the speakers, with Diana’s voice closer to the front wall of my room. In general, I found that the BP-173 placed vocals just slightly further back within the soundstage then my BP-26 preamplifier. Diana’s voice had a revelatory smoothness and there was an exceptional control of sibilants. Bass notes were pristine, tight played with no overhang. The BP-173 was masterful in separating instruments, relating a clear sense of space between them and holding them rock solid within the soundstage. I would characterize the sonic quality of the BP-173 as one of purity, transparency, top-to-bottom control and uncompromised linearity. Though clarity and focus was exceptional, I did note that the BP-173 did not portray the guitar and piano notes with as much bloom as the BP26. My interpretation, after considerable listening, is that the BP-173 was just demonstrating its greater control and transparency to the source, while the BP-26 provided a more diffuse rendition, overlaying this apparent bloom.
On the track “Gaia” from James Taylor’s Hourglass album, the BP-173 sounded open and offered natural warmth. The rendering of low-level detail with opening synth sounds, chimes and background vocals was lucid. I couldn’t get over how much more separated and individually distinguishable the massed background voices were. James’ voice was silky and authentic, bringing intimacy to his delivery and the strums of the guitar with its authentic tone had engaging palpability. The fierce drum roll at the 4:10 mark on this track, established the fantastic transient speed and dynamic capability of the BP-173 ; putting an ear-to-ear grin on my face. I’ve listened to the track time and time again but never heard it with such visceral purity.
Preamplifiers can’t be underestimated in their influence. Sitting between source and amplifier, they have direct impact on all music signals. Purists seek those which have least impact - “a wire with gain”, while musical romantics seek specimens that impart the sound they desire. If you’re one of the former camp, I have no higher recommendation than the BP-173. In my experience, it is superlative in its linearity of tone, clarity, definition, transparency and control. I caution those who might pair it with lesser sources, as the BP-173 is a tell-it- like-it-is preamplifier. With beautiful recordings you will be swept to the highest realms of appreciation, yet don’t expect it to hide the freckles on those poor recordings or upstream components. With other preamplifiers you might get more warmth, softer images or more bloom but I’m not aware of anything near the price of the BP173 that will allow you to peer so deeply into the music and get so close to the truth of recordings.
Bryston BP-173 Cubed Series Preamplifier
Price: $3,995 US