mbl 1611HR D/A converter & 1621 CD transport Associated Equipment
Most of the extended listening for these reports was done with the California Audio Labs CL-20 CD/DVD player as the source. I made this choice to eliminate any possible bias from using a transport designed and constructed to mate to a specific DAC. As the common source, the CL-20 provided both S/PDIF (coax and optical) and AES/EBU outputs, as well as CD/DVD compatibility with up to 24/96 digital output. I did this also to maintain a level playing field without auditioning all the possible combinations of transport and DAC and interconnection. Let's see: three DACs times four transports makes 12 combinations, without even considering digital (balanced, unbalanced, optical) and analog (balanced, unbalanced) connection options. Then there were the Burmester 970's 400+ internal configurations! Unfortunately, the CL-20 has a maddeningly slow control interface, and is much less sophisticated and satisfying than the Burmester 969, the mbl 1621, or the sleek, efficient Meridian 508.24.
The CAL CL-20 transport was firmly seated on a Bright Star Big Rock. The rest of the system consisted of my Sonic Frontiers Line 3 preamp, Sonic Frontiers Power-2 or McCormack DNA-1 (Rev.A modifications) power amps, and PSB Stratus Gold i loudspeakers. Digital interconnects for extended listening were Straight Wire AES/EBU or Illuminati D-60 coax, with various TosLink and ST-glass cables used from time to time. DAC-to-preamp cables were the JPS SuperConductor2, in balanced and unbalanced varieties, and preamp-to-amp cables were balanced JPS SuperConductor2. Speaker cables were the Straight Wire Maestro II.
I was fortunate to have an entire alternative reference system in the form of a Meridian 508.24 CD player/transport and a pair of Meridian DSP-6000 powered loudspeakers. While this entire system differed so much from the main one as to preclude direct comparisons, it often provided an instructive insight into the sounds of a particular recording, which, in turn, shed light on the more subtle distinctions between the DACs under test. Sort of like having an opinionated but informed kibitzer looking over my shoulder.—Kalman Rubinson