1 Topic by dyonight (edited by dyonight 2022-01-08 17:18:43)

  • Registered: 2013-11-14
  • Posts: 30

Topic: Wordclock termination

Hi!

I always took for granted that the last element in the wordclock chain should have a 75ohms termination.

Now I want to add a Mytek Stereo192 ADC to my RME Madi Fx and clock it with a BNC cable (RME master).

When I look at the Mytek manual, here's what I find:

"Connect this jumper when Stereo96 ADC is the last destination in a chain fed
by external wordclock source and the cable is long (above 6ft). For short cables
and wordclock sources with unknown drive capability JP5 should be left
unconnected (unterminated) "

My BNC cable is 1 feet long, so....

Any expert can explain a bit more? According to Mytek I should leave the A/D unterminated even if it is last in the chain, cause I'm using a short BNC cable.

That's what I'm going to do even if I don't get it at all.

Thanks!

  • ramses
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  • Registered: 2012-10-14
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Re: Wordclock termination

Each digital output contains the clock signal, usually no need for word clock.

What Mytec do you have in particular ? What digital inputs does it have ?
What other devices do you have connected to your HDSPe MADI FX ?

It might be possible to use also a digital output from one of the devices that are connected to MADI.

A little bit more information about devices / cabling would be helpful to give you good recommendations.

BNC is indeed not so picky compared to former computer based networks based on BNC cables.
You will see if you get a stable lock -> sync.

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13

3 Reply by dyonight (edited by dyonight 2022-01-08 18:01:13)

  • Registered: 2013-11-14
  • Posts: 30

Re: Wordclock termination

Thanks for your answer but the rest of my setup is irrelevant for what I'm asking here.

Should I terminate the Mytek ADC with the internal jumper?

Madi FX -> 1 feet BCN -> Mytek ADC192 (That's it)

1. What are the symptoms of an incorrectly terminated word clock? Jitter with pops and clicks I guess?

2. Why does Mytek recommend leaving it unterminated?

3. If it works it works? The "Lock/Sync" status will tell me?

Thanks!

  • Registered: 2013-11-14
  • Posts: 30

Re: Wordclock termination

I will test it terminated, I've never seen anywhere that terminating a short connection could be detrimental even if not necessary.

5 Reply by MC

  • MC
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Re: Wordclock termination

3. Exactly.

Short cables have only low capacitance, so the ringing effect (that termination prevents) is not there. Not using a termination then gives higher level and as such more reliability in real-world usage.

Regards
Matthias Carstens
RME

MC's Website

  • Registered: 2013-11-14
  • Posts: 30

Re: Wordclock termination

Yessss! Thanks MC! Unterminated it is then! (And thanks for telling me why!)