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bsfreq
Joined: Jul 27 2017
Posts: 8

H9000 MADI termination

bsfreq
February 20, 2020 - 10:30 am

Hello,

I’ve been using MADI optical so far, so I did’t have to think about termination earlier.

Now, as the H9000 MADI uses only 32 channels (half of the available 64 MADI channels on my interface), I would like to connect my H9000 to my interface via MADI coaxial to free the MADI optical for other use. 

The H9000 MADI expansion came with install instructions only, with no additional information, and no mentioning about internal termination. (At least there's no setting for MADI termination H9000 settings, only one for word clock.)

So..

Is this the correct way to connect and terminate? :

 

From RME MADI out coaxial -> 75ohm BNC cable -> 

BNC T-connector -> H9000 MADI in coax.

                    |___  ->75ohm resistor at the other end of the T-connector.

and

from H9000 MADI out coaxial -> 75ohm BNC cable -> RME MADI in coax (with internal 75ohm termination)

 

If I understand this correctly, each Coaxial MADI out works the same way as WORD CLOCK out, so that each MADI output has to be terminated at the end of the chain, even when only using one sending, and one receiving device??

So MADI out / in loop between two devices would have to be terminated at the input of both devices?

I should also mention that my interface sits on top of my H9000, so the BNC cable lenght will be short, only 0,5m or less. I read somewhere, that short cables with no T-connectors would not need termination, but I would like to know for sure, and hear from Eventide what is the case here.

 

 

Thanks for your help.

 

Tags: 
Eventide Staff
jbamberg
Joined: Aug 22 2011
Posts: 161
jbamberg
February 23, 2020 - 11:04 am

bsfreq wrote:
Hello,
I’ve been using MADI optical so far, so I did’t have to think about termination earlier.
Now, as the H9000 MADI uses only 32 channels (half of the available 64 MADI channels on my interface), I would like to connect my H9000 to my interface via MADI coaxial to free the MADI optical for other use. 
The H9000 MADI expansion came with install instructions only, with no additional information, and no mentioning about internal termination. (At least there's no setting for MADI termination H9000 settings, only one for word clock.)
So..
Is this the correct way to connect and terminate? :
 
From RME MADI out coaxial -> 75ohm BNC cable -> 
BNC T-connector -> H9000 MADI in coax.
                    |___  ->75ohm resistor at the other end of the T-connector.
and
from H9000 MADI out coaxial -> 75ohm BNC cable -> RME MADI in coax (with internal 75ohm termination)
 
If I understand this correctly, each Coaxial MADI out works the same way as WORD CLOCK out, so that each MADI output has to be terminated at the end of the chain, even when only using one sending, and one receiving device??
So MADI out / in loop between two devices would have to be terminated at the input of both devices?
I should also mention that my interface sits on top of my H9000, so the BNC cable lenght will be short, only 0,5m or less. I read somewhere, that short cables with no T-connectors would not need termination, but I would like to know for sure, and hear from Eventide what is the case here.
 
 
Thanks for your help.
 

I will forward your question to someone who knows more about these things than I do and follow up with the answer, but I can tell you that in my test setup in my office, I use an RME MadiFace connected to the H9000 MADI card using coax cables with no T-pieces or external termination at either end without any issues.  My cables are probably 3-4 feet long if I remember correctly.

 

Eventide Staff
jbamberg
Joined: Aug 22 2011
Posts: 161
jbamberg
February 23, 2020 - 12:21 pm

Here's the lowdown:

MADI is not like word clock.

MADI uses 75 ohm coax, but is point-to-point only and does not allow daisy-chaining. Thus, it does not require any external termination -- this is done internally on both transmitter and receiver ends. T-connectors should never be used.
The proper connections would be:

RME MADI out --> 75 ohm BNC cable --> H9000 MADI in.
H9000 MADI out --> 75 ohm BNC cable --> RME MADI in.
 

bsfreq
Joined: Jul 27 2017
Posts: 8
bsfreq
February 23, 2020 - 03:58 pm

jbamberg wrote:

The proper connections would be:

RME MADI out --> 75 ohm BNC cable --> H9000 MADI in.
H9000 MADI out --> 75 ohm BNC cable --> RME MADI in.

 

Perfect. Thanks for your help! I'll just order the BNC cables then and save a few bucks, not having to buy T-connectors and resistors.