Rebbi, I don't have any of those recordings, but based on what Jim and Bill have said I would expect that the major contributor to the problem is the system rather than the recordings. Given that, and given that "jitter" (high frequency random or pseudo-random fluctuations in the timing of D/A conversion) is generally recognized as being a major and pervasive issue in digital audio, which can cause or contribute to sibilance, and given that jitter can be heavily influenced by the transport-to-DAC interface, a couple of experiments would seem to be in order (in addition to what Jim has suggested):
1)As an experiment, try temporarily putting a cheater plug (a 3-prong to 2-prong adapter, with the safety ground pin left unconnected) on the AC power plug of the DAC, and perhaps also on the AC power plug of the CD player you are using as a transport. That will break any ground loops between the two components, which can often be a significant contributor to jitter in a coaxial S/PDIF interface. The cheater plug on the DAC will also break any ground loops between the DAC and the preamp, which conceivably could also be a factor.
In saying this, btw, I'm assuming that you are using a 75 ohm coaxial cable, intended for digital applications, between the CD player/transport and the DAC. I see that your CD player/transport also provides a Toslink output, which would be immune to ground loop effects but has other downsides, including some that make it susceptible to jitter, which chances are result in its being the less desirable of the two interfaces.
2)If and as possible, try different cables between the CD player/transport and DAC, and in different lengths. It might even pay to try an analog RCA cable, although theoretically that is not ideal. What length will be optimal cannot be predicted with any certainty, as it depends on unspecified and unknown variables such as the risetimes and falltimes of the CDP's digital output signal. But odds are that either a very short length (less than 1 foot) or a fairly long length (5 or 6 feet or thereabouts) will stand the greatest chance of providing optimal results.
Hope that helps. Best regards,
-- Al
1)As an experiment, try temporarily putting a cheater plug (a 3-prong to 2-prong adapter, with the safety ground pin left unconnected) on the AC power plug of the DAC, and perhaps also on the AC power plug of the CD player you are using as a transport. That will break any ground loops between the two components, which can often be a significant contributor to jitter in a coaxial S/PDIF interface. The cheater plug on the DAC will also break any ground loops between the DAC and the preamp, which conceivably could also be a factor.
In saying this, btw, I'm assuming that you are using a 75 ohm coaxial cable, intended for digital applications, between the CD player/transport and the DAC. I see that your CD player/transport also provides a Toslink output, which would be immune to ground loop effects but has other downsides, including some that make it susceptible to jitter, which chances are result in its being the less desirable of the two interfaces.
2)If and as possible, try different cables between the CD player/transport and DAC, and in different lengths. It might even pay to try an analog RCA cable, although theoretically that is not ideal. What length will be optimal cannot be predicted with any certainty, as it depends on unspecified and unknown variables such as the risetimes and falltimes of the CDP's digital output signal. But odds are that either a very short length (less than 1 foot) or a fairly long length (5 or 6 feet or thereabouts) will stand the greatest chance of providing optimal results.
Hope that helps. Best regards,
-- Al