Linn Majik DS-I D/A integrated amplifier Manufacturers' Comment #2
Editor: The measurements from the Majik DS-I's S/PDIF-TosLink inputs [offered in the Follow-Up of the DS-I] are at the limit of the test equipment (footnote 1). It is consequently not possible for the same test equipment to demonstrate the superior jitter performance of the Ethernet configuration.
We are able to measure the audio master clock (MCLK) inside the Majik DS-I, and what we find is that the MCLK recovered from the S/PDIF receiver (fig.1) has about eight times the jitter of the MCLK that is used for Ethernet audio (fig.2).
Fig.1 Linn Majik DS-I, histogram of audio master-clock timing accuracy with S/PDIF connection.
Fig.2 Linn Majik DS-I, histogram of audio master-clock timing accuracy with Ethernet connection.
Nevertheless, indeed there is an additional jitter component at 200Hz during Ethernet playback. This is caused by processor loading of the power supplyduring Ethernet playback there is processor activity at regular 5ms intervals. The Majik DS-I is an integrated product that inevitably does not have such good power-supply isolation between different parts of the circuit as we have in the Linn DS source-only products.
There is a small element of the 200Hz getting to the DAC's power supply, and this is apparent on the measured graph. It is worth noting that this disturbance is not audio-correlated, so is unlikely to have an audible impact. Gilad Tiefenbrun, Linn Products
Footnote 1: It is fair to point out that the Audio Precision SYS-2722's resolution does exceed that of the DS-I and that the spuriae shown in my jitter measurements taken at the DS-I's line-level outputs are characteristic of the Linn's digital circuitry.John Atkinson