• Registered: 2009-11-28
  • Posts: 1

Topic: Digico and ADI 648 Word Clock Problem using MADI

Hi there,

actually we are recording the actual PUR Tour and we have a fairly intresting issue.
The recording setup on the analogue mobile is Digico MADI to MADI ADI648 electrical in, filter out the controller singnal on channel 57 and then send the MADI signal via lightpipe to the truck using three SSL Alphalinks to convert into analog signals.
The Digico desk used by the production sends a master clock at 48006 sometimes changing to 48007 Hz.
In undefinable time steps an error occures, hearable as a resysnc over all 56 channels.
Now we took the word clock from the desk as clock master not anymore the MADI implemented clock. That reduces the failure and speeds up the resync but until now we were not able to get the issue handled stable. The Alphalinks do not provide an SRC. Is there any unit i can use to stabilize the clock to 48000 lika a SRC for MADI without crashing the sync risking jitter or digital clicks?

I would be happy to get any solution proposals.

All the best

Ulf

  • Ulrich
  • S/Mux specialist
  • Offline
  • Registered: 2008-05-31
  • Posts: 316

Re: Digico and ADI 648 Word Clock Problem using MADI

Hi Ulf,

look here for MADI SRC:
http://www.directout.eu/front_content.php?idcat=8

However, this problem shouldn't exist at all...
Are you sure that all devices starting with the first in the signal chain are affected by the sync malfunction?

Regards,
Ulrich

3 Reply by sf

  • sf
  • ADAT user
  • Offline
  • Registered: 2007-05-20
  • Posts: 15

Re: Digico and ADI 648 Word Clock Problem using MADI

Ulf,

48006 Hz to 48007 Hz from the console is quite far off the nominal value, it's not at all within the limits for a digital audio reference signal (DARS) according to AES11.
Is there a chance to use a word clock source for the console with a frequency closer to 48000 Hz, e. g. the ADI-648?
While the ADI-648 will lock to any frequency between 30 kHz and 50 kHz, it may be possible that the Alphalinks can only lock to frequencies closer to the nominal values. Do you have techical information from SSL about the lock range of these devices?

The DirectOut Technologies MADI.SRC would help here too. It can be used for filtering channel 57 and output a clean 56 channel MADI frame at the desired sample rate.
Please contact us, if you need help.

Kind regards,
Stephan Flock
DirectOut GmbH
www.directout.eu