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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