Perhaps it was serendipity, perhaps inevitability, that led me to play The Modern Jazz Quartet’s The Last Concert. “Softly, As In a Morning Sunrise” unfolds kaleidoscopically, somehow by turns psychedelic, funky, dapper, bluesy, and sly. “Summertime” blossoms open with a novel hypnotic repeating figure on the vibes that we cannot help but hear through the haze of the late 60s, then morphs through variations both familiar and enlightening, ultimately returning to the dreamy, gauzy reverie whence it all began. So what do we have here? Masters of effortless ensemble musicianship, leading us on a journey—their journey—through the decades of their storied careers.
I hadn’t expected this sort of musical revelation, but I have gratefully come to accept such delightful rewards from the technically evolutionary but musically revolutionary Bryston BDA-2 digital-to-analog converter.
Bryston’s BDA-1 DAC has been a cornerstone of my reference system for several years. Frankly, I have found little to criticize about its performance, which has earned justified praise and a Golden Ear Award in these pages. Thus, my curiosity regarding what improvements those clever Canadians might have incorporated into the new BDA-2 was tempered by an “if it ain’t broke, don’t fix it” wariness. That concern was effectively up- ended the moment that I began auditioning the BDA-2.
The most notable new feature added to the BDA-2 is an asynchronous USB input capable of handling all standard sample rates up to 192kHz, replacing the “convenience feature” adaptive USB input of the BDA-1. Bryston’s USB implementation aims to be state-of-the-art, featuring proprietary firmware running on the XMOS USB Audio micro-controller platform. The addition of this feature alone fully justifies the minor price differential over the BDA-1, which remains in the Bryston product line, albeit now at a reduced price. Whereas the BDA-1 utilized a pair of time-tested 24-bit Crystal CS4398 DACs, one per channel in a dual-differential configuration, the BDA-2 has been upgraded with the latest top-of-the-line 32-bit AKM 4399 DACs. Of course both products feature Bryston’s venerable discrete Class A analog output circuitry, rather than off-the-shelf IC op-amps. The BDA-2 retains the input flexibility of its progenitor, with two TosLink optical, two RCA, and two 75-ohm BNC SPDIF inputs, and a balanced AES/EBU input. Both single-ended RCA and balanced XLR analog outputs are offered, as well as a convenient RCA SPDIF pass-through digital output.
Inputs can be selected via front-panel switches or Bryston’s BR2 system remote control, which also enables the user to toggle the BDA- 2’s upsampling function from the listening position. This feature synchronously upsamples the input data to either 176.4kHz (for 44.1 and 88.2kHz signals) or to 192kHz (for 48 and 96kHz signals), thereby preserving all the original sample data while interpolating intermediate values at the higher sample rates. In contrast, asynchronous sample-rate-conversion techniques essentially synthesize an entirely new data set from the input signal (with the disquieting implication that none of the original input data are rendered with bit-perfect accuracy). I found that upsampling could smooth the rough edges of some older pop CDs, but that the majority of recordings sounded best when decoded at their native sample rates. An array of front-panel LEDs displays the input sample rate, though the arrangement of those LEDs would have been more logical with the left column indicating 44.1, 88.2, and 176.4kHz (rather than 44.1, 48, and 88.2) and the right column indicating 48, 96 and 192kHz (rather than 96, 176.4, and 192kHz). Consider this nit-picked.
Since the asynchronous USB input is the BDA-2’s most eagerly anticipated new feature, let’s begin our listening therewith. Apple’s Macintosh operating system natively supports USB Audio Class 2 devices such as the BDA-2 in versions 10.6.4 and above. Microsoft Windows users need to install the driver supplied by Bryston on a USB key (literally the USB “stick” resembles a metal key).