Just to inform you of how my issue got solved (it took this long because I had big health problems throughout 2024).
After checking with the ADAT loop method on the Fireface that the problem was coming from the Ferrofish, I wrote again to the Ferrofish people.
They seemed to recognize the problem, sent me a quote for it, that I accepted. I sent them the machine and they sent it back to me repaired more or less a month later. Now it works like a charm.
I have to say I didn't ask for any details about the cause of the issue. All I know is that some components had to be replaced.
You should write to them, they're very reactive, efficient and friendly.

info@ferrofish.com

i seem to have the exact same problem... did you ever find a solution? im getting crazy!

all the best

I'm posting here after having looked in the Ferrofish and RME forums and everywhere I could on the web. I found people here with sort of similar issues, but without any clear solution and with different setups.

My setup consists in an RME Fireface 802 FW soundcard, connected by the two ADAT in/out pairs to a Ferrofish A16 mkII converter.
I love both devices and am really pleased with them until recently..:

After years of perfect functioning, from one day to the next, the communication between the two units stopped working properly, making it impossible to make recordings through the Ferrofish inputs.
I only use 44,1 or 48kHz as sampling frequencies for recording and/or playback.
Sometimes the meters of the Ferrofish work, sometimes not. Sometimes I hear a few crackles, sometimes total silence.
In the Ferrofish Status page, the two ADAT signals are seen, but not locked.
On the Fireface the two leds ADAT 1 and ADAT 2 don't lit up, or sometimes just for an instant.

Apart from this issue, the Fireface works perfectly in all other situations.

Here are the links to two little videos where you can see the problem :

https://www.dropbox.com/s/h3dfzwtf3jpa9 … 1.MOV?dl=0

https://www.dropbox.com/s/dd32pqajj2pze … 2.MOV?dl=0

I made all the troubleshooting I could, to no effect :

- tried another set of TOSlink cables.
- tried all sync configurations where the A16 is the master and the Fireface the slave and vice-versa.
- resetted the A16 to the ADAT preset as explained in the manual.
- tried to give more air in between the devices in the rack so they heat up less.

I am sending this email to both RME and Ferrofish, as I couldn't tell where the problem comes from exactly for the lack of other ADAT devices in my possession.

I am a french musician splitting my time between France and Berlin, where the two devices currently are.
So, any tip of a repair person in Berlin would be great, by any chance...

Sorry for the very long message !
Many thanks in advance for any help !