The unprecedented resolution of the Alpha DAC Reference Series allowed and demanded further development and perfection of digital algorithms and analog circuitry that otherwise would not have been possible. The lengthy development process that resulted in the Alpha DAC Reference Series 2 was challenging and resulted in design improvements that we feel again define the edge of what is possible. The only way to appreciate the level of performance achieved by the Alpha DAC Reference Series 2 is to listen to it.
The presence and sonic reality of the Reference Series 2 is also made possible by tremendous electrical and mechanical noise isolation coupled with extreme time domain stability. Ceramic aerospace circuit board materials are used in all critical areas and the enclosure is carefully engineered to minimize electrical noise and maximize mechanical and thermal stability. The Reference Series 2 weighs 30 pounds and the entire enclosure is precision machined from solid billet 6061-T6 aluminum alloy.
A high output metal IR remote control with direct input source selection is provided with the Reference Series 2.
Careful consideration was given to providing the highest possible fidelity reproduction of DSD files by the Alpha DAC Reference Series 2. 99+% of modern DAC’s, including the Alpha DAC Reference Series 2, use multi-bit D/A converters because they provide better performance than 1-bit converters - even DAC’s who advertise “native” DSD compatibility. So, at some point, the 1-bit DSD stream must be converted to multi-bit for all of those DAC’s.
Berkeley Audio Design could, like many other manufacturers, convert 1-bit DSD to multi-bit within the Alpha DAC Reference Series 2 and show “DSD” in the front panel display. That would be the easiest approach from a marketing standpoint and would also be very simple and low in cost to implement. But that approach would also mean increasing the amount of processing in the DAC during playback which would degrade audio quality, and audio quality is the reason the Alpha DAC Reference Series 2 exists.
Virtually all reproduction of DSD files using external DAC’s is with a computer based music server as the source. If 1-bit DSD to multi-bit conversion is done first in the computer it can be performed with extremely high precision and superior filtering that preserves all of the content of the DSD file. Computer DSD to multi-bit conversion can be at least as good as that performed in a DAC and without adding processing noise near or in the D/A converter chip. Also, conversion of DSD to 176.4 kHz, 24 bit AIFF or WAV files can be done ahead of time resulting in no conversion processing occurring during playback. Another advantage of computer based DSD to PCM conversion is that if higher performance DSD versions such as DSD 4X appear in the future, they can be easily supported with a software upgrade.
For all of these reasons, DSD capability for the Alpha DAC Reference Series 2 is provided by a state of the art software application, JRiver Media Center, that provides either real time conversion of DSD 1X and DSD 2X to 176.4 kHz, 24 bit PCM during playback or, for the best possible audio fidelity, easy conversion to 176.4 kHz, 24 bit AIFF or WAV files prior to playback. The JRiver Media Center software application is included in the price of the Alpha DAC Reference Series 2 and either Windows OS or Mac OS versions are available.