MSB Platinum Link Plus D/A processor
In fact, the most significant trend I see in the progression from the original Link DAC to the DAC II and DAC III is the ease and convenience for the user of enhancements such as balanced outputs, HDCD, upsampling, and better power-supply options. MSB gilds the lily by offering Half-Nelson, Full-Nelson, and Gold versions, each with a higher quality of parts.
Of course, one can go only so far with such an approach, and MSB acknowledges this by offering their Platinum Link Plus DAC and its sibling, the Platinum Reference CD player. These designs start with a much more technologically advanced platform than the regular Link series: four dual 24-bit/100Mbit/s, sign-magnitude, R2R-ladder DACs which are custom-designed by MSB. The intent is to achieve true 24-bit performance by paralleling, for each of the stereo channels, two DACs with 23-bit resolution per signal phase. These outputs are combined to drive each side (+ or -) of the balanced output directly without any additional analog stages or filters. For coax output, the outputs are combined differentially. In both cases, DC offset is supposedly nonexistent; therefore, no servos or (de)coupling caps are required on the 75 ohm outputs.
Of course, we expect upsampling and other options with an MSB product, and the Platinum Plus has them aplenty. Just look at the front panel: Beginning on the upper left, the first button-LED pairing, labeled 4x Upsample On, indicates that incoming data can be upsampled 4x, up to 192kHz, or left as is. The Option button-LED is reserved for future use with an optional remote-controlled stepped attenuator. Below this are the Input Select button and its associated row of LEDs, which indicate which of the five inputs is in operation. Left in Auto mode, the Platinum Link Plus will select the active input by itself; you can override that selection manually.
At the top of the right-hand column of button-LED pairs is one for 16x interpolation. Pressing this button switches between 8x and 16x. While MSB's manual says that "Interpolation is much like oversampling," it offers no further distinction between the two. It does suggest that "16x is more appropriate for low sampling rates and 8x would be better for 96kHz or 192kHz sources."
Next down is Filter On, which adjusts the slope of the digital filter. MSB suggests the default gentle slope for higher sampling rates and the brick-wall filter for low sampling rates, but, again, without real explanation. The bottom button-LED, Phase Invert, inverts the output polarity in the digital domain.
Compared to the front panel, the rear is fairly self-explanatory. The upper left has one pair each of RCA and XLR output jacks, along with a pair of analog XLR inputs, which bypass the DAC. MSB suggests that the latter might be used for the analog outputs of an SACD player. This turned out to be quite handy—I could alternate between SACDs and CDs with the Sony XA-777ES SACD player and, with the MSB's auto-switching of active inputs, get CD through the Link Plus's conversion and SACD direct. I could also easily compare the D/A conversions of the MSB and the Sony, but no more easily than with my preamp.
The middle portion of the rear panel has AES/EBU, coax S/PDIF, and TosLink digital input jacks. On the extreme right are two CAT-5 connectors—proprietary MSB Network inputs that can accommodate multiple inputs, channels, and control lines. I had no devices with which to use this; see the MSB website for a full explanation. At the bottom of the rear panel is a standard IEC power connector, a voltage selector switch, and a DIN connector to provide power to an auxiliary device.