I’ll try to outline :
So I have a Behringer UMC1820 and have a MoTU 2408 mk2 connected to that via ADAT.
MoTU 2408 is standalone. Now tbh I didn’t realise I could go Analogue to Digital or D to A with the 2408 standalone. I thought that it would only convert TDIF / ADAT. So that’s a pleasant surprise.
Oddly there’s a mismatch in the analogue channels to ADAT channels.
eg Going Analogue to ADAT (and then into the pc DAW) - to get a signal on ADAT1 s seen by the DAW (Reaper) I have to plug into analogue input 4 ! Working at 48kHz so not a SMUX thing.
I don’t know if this is a known "feature" or if internal connections have been swapped.
Now to my clocking issue:
I originally picked up the 2408 for future use in converting TDIF / ADAT using my old Sounscape / Sydec kit. This runs on a Mixtreme PCI card. I figured I should be able to use an SS8io-3 converter box as a TDIF source / destination or interface to the Mixtreme PCI card in the old PC.
But there are “issues”:
Clocking the SSio8-3 via TDIF – it indicates lock at first – solid LED – but observing it more closely shows that is periodically flashing ie unlocked. Detail depends on whether 44.1kHz or 48kHz but typically looks ‘locked’ for a few seconds before flashing. This repeats continuously.
Using the SS8io-3 as DtoA and listening to the output gives the result you might expect. Get audio when the LED is solid and broken up audio when it’s flashing.
Similar result can be seen when clocking the Mixtreme PCI card via TDIF – lock indicator on the software mixer periodically flashes.
Now there seems to be some confusion about TDIF sync and the various 2408 versions.
I believe that the very first TDIF spec did not necessarily embed a L/R clock thus necessitating a separate clock signal eg Wordclock or Superclock. But the TDIF-1 spec’ does include L/R clock lines.
And given the timeline I’m fairly certain that the 2408 mK2 should conform to this.
But never say never. The SS8io-3 also has external clock in/out. These can be set as Wordclock (Fs) or Superclock (256Fs – or is it 512 ?) Anyway I believe the Wordclock out of a 2408 is Fs so gave it a go.
In this configuration the Lock LED is solid. So far so good. But listening to the audio, it’s just high level broadband noise. Although a bit more investigation shows that it does play the audio for a few seconds after power on but it switches to noise after that and never recovers until power (to the SS8io-3) is cycled. Now historically there is an issue about the phase of external clock signals to the TDIF data. I was developing with Mixtreme back in the 90s and the issue was a matter of some contention between Sydec and Tascam. Anyway the SS8io-3 is configurable (via DIP witch) to have clocks at 0 degrees or 90 degrees relative to the TDIF data. And similarly for the Mixtreme card via the Soundscape software mixer.
Sounds promising but makes no difference to the result !
Now, in a way I don’t really need to do this now since I can A/D or D/A with the 2408 and the connection is a preferred TRS rather than unbalanced phono plugs. But I’m fond of the Mixtreme kit and would like to retain the option / flexibility. And also out of technical curiosity.
I’ll add that the Mixtreme and (2x) SS8io-3 work solidly in their own right. Mixtreme as master and TDIF Sync. However they can effectively only work up to Windows XP so I’ve been dragged into the modern age
So any ideas here appreciated.
Thanks for reading.