Can you take a screenshot of the HDSP Settings app and upload to a dropbox or something to share here? Most likely you have a wrong setting somewhere.

No broken ADAT "doors" on the RayDAT card?

@ Jeff: I will do this evening. However since the card is master there's not that much freedom degree.

@MC: This sounds like a known issue. Is there a specific series of cards affected or a general problem maybe in combination with some devices?
As you can imagine I not simply tested one input but all. And I can hear slightly differences in the amount of sync losses.

ADAT 4 is worse, ADAT 1 is best.

Oh really ? This is new to me. I always thought that the device with the better clock is preferred to be taken as master.

EDITED in different paragraphs, pls reread:

Vinark, many thanks for the very interesting article.

I am a little short on time and read only up to the part where they start comparing different master clocks. I think the relevant information for this thread was in the 1st half anyway.

According to the article it would be beneficial to use the Yamaha mixer as clock master, as it has the ADDA converter, not the RayDAT which works only digitally.

An alternative could be to use Word Clock between Yamaha and RayDAT using the word clock module for RayDAT. But from past forum articles from RME and reading their handbook(s) I have a certain feeling / understanding that RME recommends to use WC only in cases where you should or even need to use it (big stuido infrastructure with multiple ADDA's and video recording/editing as pointed out in the SOS article).

If I didn't understand wrong, steadyclock via i.e. ADAT could be better than using WC as the frequency is higher and you do not work with a high multiplier like with a WC. But I am not 100% sure on this tbh and eventually would need to re-read RME handbook.

I think the clocking information for the pure digital communication via ADAT should be fine enough in any case. Preferrably with clock coming from the device which has A/D and/or D/A converters build in.

BTW .. the SOS article also points out, that the requirements for the digital transfer are not so "strict" compared to ADDA conversion. So RMEs steadyclock mechanism via ADAT should be well enough in any case.

So to sum up it appears to me that:
1. the best solution for him is to use the Yamaha as clock source via ADAT under the assumption, that it has a good built-in clock.
2. if this shouldn't work well, one could use RayDAT as master using the steadyclock information sent through ADAT
3. next option to use WC, eventually the RME clock as master, as I would think that the RME clock in a separate unit might be better than in a complex compact mixer, where the quality of such modules / circuits could be a matter of a price compromise.

To know it exactly I fear you need to measure, this means efforts and devices which a normal user usually not has.
I would say, if it works like we think it should work well and if this does not hurt, continue to use it the way it works

I would open a support case with RME support.

But it would be very nice if RME could follow up on this here in the forum.

I also would like to learn, what goes right or wrong in your environment and whats best practise.

Times are gone where I thought that WC is the best in any way. I had to learn from this RME forum that it also depends on the quality of the WC chip on each particular device and so on and so on. Many things to consider it seems, especially after reading the SOS article as suggested by Vinark.

I am not technician enough in this area, so I stick out of this now and wait if RME could kindly involve
to looks whether there is an issue with your HW and maybe also whats the best solution in your case.

When using the yamaha as master it works and with respect to my measurements the signal quality was the best at all.

One drawback is the SPDIF source. So far I've connected the SPDIF input of the Yamaha with the mainboard sound for normal audio PC use. Furthermore the onboard Realtek chip can loop through the (internal) SPDIF input of the board to its output.

So I'm thinking about connecting the external SPDIF to the RayDAT and connecting the electrical signal the mainboard input too. I.e. the Yamaha could lock to the external SPDF via mainboard (or alternatively to the onboard audio) and the RayDAT could lock to the Yamaha (or theoretically to SPDIF directly).

Of course that's very unusual.

I returned the (second-hand) RayDAT back since I was unsure wether the card was defective or had the TOSLINK inputs to be changed.
Hoping a new card will work better I bought a new one. And here's the result:

Configuration: RayDAT = master

Using ADAT1: sync seems to be stable when transmitting test signal from mixer via PC back to mixer
.
.
using ADAT4: 1 sync error detected over several minutes using the same test signal.

The card was shipped with FW version 13. I couldn't detect any differences after updating to 14.

Using ADAT1 I started playing an external synth (signal passed through the mixer to the PC and back to the mixer).
And sh...., several sync errors occured (depending on signal).

I.e.: The new card has less sync error problems but the problem still persists.

Using the mixer as master again everything works.

The technical data of the card promises state of the art jitter reduction.

So this is my question to the engineers: Why is a Hammerfall DIGI9636 or a miniDSP USB/ADAT adapter working without any problems and the RayDAT not?

I feel that the RayDAT doesn't provide any jitter reduction at the inputs when working as master but only when working as slave.

Since this is a new card compared to the roughly 8 years old card the problem you mentioned still persists?