The Compact Disk standard was never conceived with the notion of distinctly separate transport and DAC sections but once this became so, SPDIF was adopted as the method to link the two together. However, SPDIF is an analogue transmission system that uses what was originally a video signal format to transmit a digital system. Clearly, this is not an elegant solution as the SPDIF clock and signal are transmitted together as if the red, blue and green signals for a television were cobbled into a single run.
At AMR, to overcome this set of essentially analogue problems we devised a completely analogue solution. AMR’s proprietary Valve Digital input technology (VDi) is a world’s first: it is the use of the NOS 6N11 (high-speed valve operating into the 100MHz region) in a zero feedback circuit derived from military radar technology to re-establish the clean waveform of the original incoming signal from the two HD SPDIF Inputs.
Firstly, this ensures that even if the input SPDIF signal has an incorrect output level or poor waveform, the SPDIF input receiver will have a clean and perfect SPDIF signal to lock onto.
Secondly, as all SPDIF receivers use Schmitt Trigger input circuitry, the receiver will create a glitch noise at the trigger point, this noise travels back into the SPDIF cable, returning to the source component. It is this errant noise that is at least in part responsible for the major differences between SPDIF cables and sources in the input system of common DACs. As the HD-VDi isolates the SPDIF receiver from the outside world, HD-VDi eliminates the detrimental effect caused by this noise once and for all.
The DP-777’s HD SPDIF inputs employ a NOS valve input circuit for everything all the way up to the 24/192 high-definition standard. The result is clearly visible on an oscilloscope as the SPDIF signal is restored back to its perfect wave form. This input ensures the “right note at the right time” to give the music the “life” that is missing from all other DACs.
(hviler vel bl.a. på skuldrene til selveste Kondo san). Spiller daglig på en Loesch designet preamp selv. Den måtte dog seriøst moddes før den var brukanes, men, men dreper vel ikke mannens kunnskapsrikdom det
