1 Topic by skioutsoukis (edited by skioutsoukis 2025-08-30 19:12:46)

  • Registered: 2020-04-01
  • Posts: 24

Topic: Use RME M-1620 Pro as a gPTP Grandmaster in AVB/MILAN setup

As we all know in an AVB/MILAN ecosystem the clock is provided by the elected gPTP source, which will usually be the main AVB/MILAN capable switch.

This fact takes out of use (for the connected AVB endpoints) the advantages of a more accurate clock signal filtered by steady clock fs function. Yes the clock provided by 1620 to ADAT/MADI/AES outputs will be benefited but the AVB endpoints will still be clocked directly from the gPTP thus loosing the benefits of steady clock fs's cleaner clock.

I am planning to buy the RME M-1620 Pro and I was wondering if anyone has an opinion or experimented if the device can act as a gPTP Grandmaster, and in this case, will the SteadyClock FS oscillator act as the true timing source distributed to the entire AVB/MILAN network?

I am already thrilled by the fact that RME gives the option to switch formats AAF/AM824.
I am also in the backlog having pre order (and also pre pay smile ) the HDSPe AoX MILAN and yet the delivery note remains to "several months" so I would appreciate if an insider has any news concerning AoX availability.

Thanks!

  • Max
  • Max
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  • Registered: 2007-05-09
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Re: Use RME M-1620 Pro as a gPTP Grandmaster in AVB/MILAN setup

AVB/MILAN ecosystem the clock is provided by the elected gPTP source,

The time is provided by the gPTP GM.
The time in the endpoints is actually free-wheeling and continuously adjusted to match gPTP GM time (syntonized). So a jittery time on a gPTP GM does not mean that the gPTP time in the endpoints also shows this jitter.
The media clock (at least in current MILAN standard) is described with gPTP timestamps.

However, incoming CRF clock also passes SteadyClock, so even if you had a very "bad" gPTP GM in your network (or the media clock is created from clock reference with jitter), the sound quality on the RME endpoints still remains the same.

In terms of audio quality, you cannot tell the difference between an internally-clocked or externally-clocked RME AVB device.

All in all really great technology, although difficult to understand under the hood.