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Upsamplers, DACs, jitter, shakes and analogue withdrawals, this is it.

Re: Your player already has fairly low jitter measurements

I would agree that jitter is not easy to measure. For example, the Miller analyser is (I believe) based on Julian Dunn's J-test method. The problem is that this does not actually measure jitter, what it's measuring are artefacts associated with perturbing a sine wave with a 1-bit amplitude square wave.

Whilst this does highlight the sort of artefacts produced by jitter, it can also highlight artefacts not related to jitter. And some jitter artefacts may not be measurable by this method.

I am less familiar with the Audio Precision instruments, but from what I understand their ADC based measuring equipment does not have sufficient precision to really measure jitter either.

I would however say that if two players are measured using the Miller analyser (which would be the case for all the recent Stereophile reviews), then it is valid to compare the measurements, in the sense that one player generates less (or more artefacts) in response to a specific test signal compared to the other [however, note: as I've pointed out, this difference may not be isomorphic to the underlying jitter differences between the players].

What I do know from examining a Sony XA777ES (note: this is a completely different design than the Sony 777ES) is that there seems to have been quite a lot of attention paid to reduce the effects caused by logic induced modulation, which is a major source of jitter, certainly more so than on a typical universal player. And having an audio clock that is not regenerated from 27MHz certainly helps. So I would suggest that the comparative jitter numbers are not surprising.

My point is that I'm not sure that jitter on this player (measured using any method) can be substantially reduced by tinkering with it. All the obvious areas have already been addressed (apart from perhaps better EMI/RFI shielding), and in any case there isn't any room to do anything really fancy anyway.

If I really wanted to dramatically improve the sound of the player, I would probably investigate replacing Sony's proprietary digital filter. The Triple DAC architecture is also a bit bizarre, it's more likely to increase rather than decrease noise (but I suspect Sony may have implemented it for euphonic reasons).


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