Linn Majik DS-I D/A integrated amplifier Manufacturers' Comment #2

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 supply—during 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 afair to point out that the Audio Precision SYS-2722's resolution does esxceed that of the DS-I and that the spuriae shown in my jitter measurements taken at the DSI's line-level outputs are characteristic of the Linn's digital circuitry.—John Atkinson
Company Info
Linn Products Limited
US distributor: TC Group Americas
335 gage Avenue #1
Kitchener, Ontario, Canada N2M 5E1
(519) 745-1158
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Comments
deckeda's picture
Trying to parse. My appologies if I missed the obvious.

1) Linn says Ethernet sounds better but doesn't explain why.
2) AD concurs.
3) JA apparently theorizes about jitter and goes looking but doesn't find meaningful differences.
4) Linn says yes, it's lower jitter that makes RJ-45 et al better but JA's test equipment can't reveal it.
5) JA says actually, yes it can.

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I didn't get a sense at all that the "stupidness" software issue has been overcome. And Linn---"open" software more often than not means everyone is free to design by committee, with predicable results. Don't tout that too strongly.

There are other facets not covered here, like why iTunes isn't a great ripper (it has a selectable error correction, giving the software more time for example) or why something that incorporates CD Paranoia while ripping wouldn't suffice.

This review is a good example of the perils of subjecting single components to scrutiny that demands investigation beyond the norm---so much more interaction occurs with computer-based music replay.

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