Euphonix MA 703 (clocking) problem
 

I own several of these units and one of them has recently started outputting cycilcal noise whilst at the same time not locking to house sync via word clock input.

The problem is intermittent and sometimes leaving the unit off for a while will make it work normally for a period of time.

I own six Euphonix converters in total and they are housed in a suspended rack which is occasionally moved between locations. The house clock is in the same rack and word clock cables are new and are never touched/fiddled with.

Furthermore, the units have built-in fans and an extra unit of rack space in between each other. The rack is suspended so there is an inch of space betwen the frame and the outside walls.

Any help is very much appreciated as is a copy of a service manual if it exists (I could not find one).

Re: Euphonix MA 703 (clocking) problem
 

Try locking to a different sample rate...does that work ?

Re: Euphonix MA 703 (clocking) problem
 

That does not work. At the moment if I switch off the unit and leave it off for a while it will work fine for some time. Then it will start emitting noise and the clock indicator will switch from 44.1/Word (Auto) to Custom/Word (Auto)



I will get a tech to look into it but would be very grateful for pointers so I do not just give him the unit and hope he can work out the rest.

Re: Euphonix MA 703 (clocking) problem
 

Yes, I'm speaking to the guy that actually fixes these and he's asking the questions. The fact it fails after it warms up points to a component failing.
So if you switch to Internal and 48Khz it still starts making noise ?

Re: Euphonix MA 703 (clocking) problem
 

That is brilliant and much appreciated, Eddie!


The MA703 can't run on internal (being a D/A only) but I did try to select MADI as sync source with the same result. It goes to Custom and outputs noise.


It did occur to me, too, that it might be temperature related.

Re: Euphonix MA 703 (clocking) problem
 

This is most likely the crystal(s). We usually replace both when we're in there.

You should measure the +/- 18Vdc rails. They should be between 17.5-18Vdc. Attached is a picture. In this picture, the 3 test-points can be seen just under the serial number label, just to the right of the black heatsinks. They're labelled +18, GND, and -18.

The pictured board is a newer version with the regulators heatsinked, the older versions have the regulators lay flat, soldered to the board.

The crystals are custom-made by Cal Crystal Comclock. High-precision. We have some we could sell you.

Re: Euphonix MA 703 (clocking) problem
 

That's great - thank you so much, Eddie. I will measure the voltage over the test points and take it from there. Since I am up against it working to a deadline it might be a few days until I can see to it. I will come back to this thread to update.


Thanks again!

Re: Euphonix MA 703 (clocking) problem
 

I might be having the same issue, my D/A emits this noise occassionally - im running it at 48khz internal clocking.

Would a masterclock solve this issue? Like a HD sync or big ben?


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Re: Euphonix MA 703 (clocking) problem
 

The D/A cannot run on internal sync so I presume you mean MADI Input. If you have the same issue an external clock will not fix it.


As I do not know your setup it's hard to give you any other advice. If the D/A is the only thing you are using then you will not need an external clock. If you have an A/D in your setup I would recommend clocking your MA703 from the A/D's word clock Out (same for your computer sound card).


If your setup is any bigger than that a word clock unit makes sense.

Re: Euphonix MA 703 (clocking) problem
 

My setup involves an AM713 and an MA703

And i connect the S5 to my Mac (daw) via a rme madiface usb (madi to usb converter, so no HD system present)

I thought of using a digidesign sync io i found in storage and use the word clock out from that and daisychain throughout the two converters and the SC264D (fusion setup, no DF66)

I have never fiddled with clocking before so im shooting blind here :)


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Re: Euphonix MA 703 (clocking) problem
 

So if I understand you correctly you have a System 5 desk plus Euphonix studio computer, a AM713 and a MA703 plus an RME sound card?

If that is the case you can try to daisy chain word clock from one device to the next, especially if they are located close to each other.

But I would consider getting a dedicated word clock unit especially if you are planning on adding any more devices requiring clocking to this setup.

The sync HD is not going to help you here as it is not a dedicated word clock generator/distributor. The only reason for having it is time code sync which is of no benefit to you as you aren't using HD hardware.

With only one A/D in your setup this unit should be running on internal sync and clock the rest of your devices. I would steer clear of word clock outputs and connect each unit with a T-Bar.

AM713 wc out
|
|
|--MA703 wc in
|
|
|--System 5 wc in
|
|
|
|--SC264D wc in
|
|
75Ω BNC terminator

The MADIFace will be quite happy locking to whatever appears on the MADI IN (and presumably the same is true for the System 5).

The only thing to keep in mind is that if you are using the coax and optical ports on the MADIFace at the same time whatever is feeding those Inputs should be synchronised to the same clock.

Re: Euphonix MA 703 (clocking) problem
 

Thank you for the quick reply! This is a massive help :)

I was told the sync io can run in standalone mode as a clock generator.

I only use the madiface to connect the coax madi from the desk to pro tools, i did however contemplate if older ssl madi converters (running optical madi) could connect to the rme aswell as im running digital monitoring and therefore only have a few analog outputs for outboard gear.


What do you mean by T-bar? Shouldnt the wc out from the MA703 carry the clock onwards to the sc264? Or am i being thick?

And what do you mean by bnc terminator?




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Re: Euphonix MA 703 (clocking) problem
 

Seeing you only have one A/D stage it is best to run the A/D on internal sync. You will gain nothing by clocking the AM713 from the word clock Output of the Sync HD - quite the contrary, actually.

No, you should use a BNC T-connector and run your word clock in parallel, terminated at the end. The end being the final T-Connector in the chain.

This is a BNC terminator. Both, the T-Connector and Terminator need to be rated 75Ω.





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Re: Euphonix MA 703 (clocking) problem
 

[/QUOTE]



Ok...

So, how would i not gain anything from syncing from the sync io? (I ask to understand)

And when you say run my word clock in parallel? What does this mean?




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Re: Euphonix MA 703 (clocking) problem
 

[/QUOTE]



Ah i get it!

Am703 wc out to T-Bar

T-bar out into ma713 & sc264D


But then there shouldnt be a loose end to “terminate”?


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Re: Euphonix MA 703 (clocking) problem
 

Ah i get it!

Am703 wc out to T-Bar

T-bar out into ma713 & sc264D


But then there shouldnt be a loose end to “terminate”?


Sent from my iPhone using Tapatalk[/QUOTE]
Just connect it like in the diagram. The word clock Outour of the AM713 has a BNC-T connected to it and so do each of the other devices' word clock Inputs. The final device in the chain has the terminator connected to it.


Ypu won't gain anything from using the Sync HD as it is best to run your A/D on internal sync. The internal clock of the AM713 runs at 64x or 128x the sample rate (not sure which but it is in the specs). This is called oversampling. If you connect the Sync HD to the AM713's word clock input the AM713 will slave its clock to 44.1kHz and then multiply that clock accordingly. This is likely to introduce jitter which results in a loss of audio quality.



You can only get so far by daisy chaining your word clock but, if done correctly and in a small setup, you will be fine clocking everything off the AM713.

Re: Euphonix MA 703 (clocking) problem
 

So i take it the clock in the sync io is worse than the clock in the am703. Ill get to it :) thanks!


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Re: Euphonix MA 703 (clocking) problem
 

So i take it the clock in the sync io is worse than the clock in the am703. Ill get to it :) thanks!


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