Clocking of Eclipse and H8000

[Fender17]

I would like to ask, is it better to clock Eclipse and H8000 using ADAT or by World Clock? Or is it about the same? The clock will go from RME interface and devices will be close to each other, so no long cables.

Clocking by ADAT would be more conveniet for me as that would mean less cables…..

[tsternfeld]

It shouldn’t make any difference whether you derive the internal sample clock from the ADAT stream or the Word Clock.  Use the one that is more convenient.

[Fender17]

Thanks. I have read somewhere that WC gives more precision, so that is why I have asked….

[tsternfeld]

That’s true-ish (with caveats): In a large, many-device setup (where some devices may be more accurate at deriving clocks than others) you may be able to get more tightly coordinated clocks more reliably and with less jitter by using a clock generator and WC to distribute the same clock to all of your devices (rather than using the carrier clocks of multiple, potentially chained and multiply recovered digital audio signals).

For a simpler system, the digital audio signals should be just as effective at delivering clock information as the WC.

[Fender17]

OK, I have RME Digiface USB to which Eclipse, H8000, RME Fireface 802 and RME Fireface UCX are connected using ADAT. And RME Octamic-D connected to FF 802 using ADAT.  And I want to use WC for clocking of Octamic as it does not have ADAT in to be clocked by ADAT (and I do not want have Octamic as master,  because I switch it on only if needed more mics in). All devices are close each other, just few feet.

It works with ADAT clocking fine, but the need to use WC for Octamic has raised the question if using WC would not be better.

I have read somewhere that jitter does does matter only on A/D and D/A, which seems to me true….. Digital computations may be done, when they are done, if they are done inside the time frame. So, really big jiter might cause problems in case heavy computing tasks…..

Am I right that if Eclipse/H8000 has lock and no dropouts and all is done digital (no A/D or D/A in Eventide unit, just digital in/out), jitter/clocking does not matter much?

[tsternfeld]

That’s correct, unless there is an issue with the clock tracking so severe that the system is losing whole samples, you shouldn’t see any difference due to the clock source (assuming all-digital operation).

Even with analog I/O, the design teams for the H8000 and Eclipse put a lot of work into ensuring minimum achievable jitter in clock recovery from any source.

[Fender17]

OK, thanks. So, I will use only optical ADAT clocking. Less connections and gear items electrically isolated.

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