Problem with 828MK3 & 8Pre Combination

fazmanicg · Post by **fazmanicg** » Sun Mar 09, 2008 12:31 pm

I have finally received my 828MK3 & 8Pre. I do have an issue though.
The 8pre is used strictly as a converter with the ADAT optical cable coming out and going to the MK3. Both units are set to 44.1.

They are both in a rack, so when I flip one switch, all the gear in the rack comes on at the same time.

What's happening is, I get no digital signal coming in to the MK3 from the 8pre. I get meters on the 8pre, so I know the input is working. In order to get the MK3 to "see" the optical input, I need t switch off the 8pre, and turn it back on. That usually does the trick, and the MK3 sees the ADAT input and I'm on my merry way.

A) I don't think I should have to do this

B) If I forget to mute the output of the MK3 before I switch the 8pre off and back on again, I get this Awful screech from the output of the MK3.

I Also tried it @ 48K, and it still acts the same.

What really gets me pissed off, and it's my own stupidity, is that I installed everything in a rack, which is extremely difficult to get at, and NEVER wrote the serial numbers down. I don't even know if MOTU will talk to me without them. I took for granted they were on a sticker on the box. What an IDIOT!

Can someone shed some light on this?

Thanks

chucks · Post by **chucks** » Sun Mar 09, 2008 12:40 pm

Could be a sync issue - screeching is symptomatic. Do you have the ADAT connected in both directions (in and out) and the 8 pre set to clock to external? The 8 pre would receive the clock on it's ADAT in.

fazmanicg · Post by **fazmanicg** » Sun Mar 09, 2008 12:51 pm

No I don't. I only have the one ADAT cable going from the 8pre's OUT to the MK3s IN. I am going to pull out the manual and read up on the 8pre. I was told all I have to do is what I did, and everything will "just work".

I'll experiment a little and get back.

Thanks!

fazmanicg · Post by **fazmanicg** » Sun Mar 09, 2008 1:12 pm

Hi Chuks,

I do not have the 8pre connected via firewire. It is only used as a converter. The manual states that I have it hooked up correctly. The ADAT inputs on th 8pre are actually disabled when no firewire cable is attached. So it has to get it's clock from the 828MK3.

I have to say, Both units are fantastic. The CueMix is a dream come true for 0 latency tracking. This is a minor inconvenience, but I would like to know if this is something I should be concerned about.

1nput0utput · Post by **1nput0utput** » Sun Mar 09, 2008 2:31 pm

What you're describing does sound like a synchronization problem. Make sure that the 828mk3's clock source is set to the optical input to which the 8pre is connect (either ADAT Optical A or ADAT Optical B).

fazmanicg · Post by **fazmanicg** » Sun Mar 09, 2008 2:36 pm

Thanks, That I have not tried yet. I will give it a test.

TuomasP · Post by **TuomasP** » Sun Mar 09, 2008 2:38 pm

I agree. There must be a way to put the 8pre to use the clock from the 828, either using a world clock bnc or adat. Otherwise you must choose the 828 to use adat in as a clock. However, I guess the clock of the mk3 is better than the one in 8pre so I would use the mk3 clock as the master. There must be a way to do so. The 8pre cannot get the clock from the 828 if you connect only the adat out from 8pre to 828.

Regarding the loud sound coming out of the 828, I would never use an audio interface without an external volume controller. You never know what happens if your audio interface crashes and blows your monitors etc. I use a passive volume controller which also helps to keep the maximum quality after d/a because you don't have to attenuate the output digitally. This made a big difference with my earlier 828 mk2.

fazmanicg · Post by **fazmanicg** » Mon Mar 10, 2008 5:55 am

This morning I set the 828MK3 to sync to the ADAT IN which comes from the 8pre. I then shut it all down. When I turned them back on, I still had no sync. I had to turn the 8pre off and back on. I then was getting the proper sync.

So, for whatever reason, No matter which device is supplying the sync, I still have to turn the 8pre on AFTER the 828MK3 has finished loading the CueMix FX ......

AGAIN - I do not have any firewire cable attached to the 8pre, so there is no driver loaded for it. And the manual states that the optical output is DISABLED when used as a converter.

This is really not that big a deal. I only need the 8pre on occasions where I will be recording more than 2 inputs at the same time, which is not that often. I might just leave it powered off when not being used. I still want to talk to MOTU though.

fazmanicg · Post by **fazmanicg** » Mon Mar 10, 2008 7:02 am

Just got off the phone with MOTU. I have to say their Tech Support is second to none. It turns out that the Optical input on the 8pre is disabled, but for AUDIO ONLY. It can still be used for clocking purposes.

I am going to run out and get a cable. I will then take the optical out of the 828MK3 and send it to the Optical input of the 8pre.

I'll keep y'all posted.

TuomasP · Post by **TuomasP** » Mon Mar 10, 2008 8:18 am

fazmanicg wrote:Just got off the phone with MOTU. I have to say their Tech Support is second to none. It turns out that the Optical input on the 8pre is disabled, but for AUDIO ONLY. It can still be used for clocking purposes.

That was my guess because the 8pre doesn't seem to have world clock bnc connectors leaving the adat input to be the only possible sync input. Anyway, good that you found a solution.

fazmanicg · Post by **fazmanicg** » Mon Mar 10, 2008 5:44 pm

Picked up another optical cable today. The 8pre is now getting sync from the 828MK3. All is well!

I would like to thank you all for leading me in the right direction.

Douglas Nagel · Post by **Douglas Nagel** » Wed Mar 12, 2008 1:40 pm

fazmanicg,

Thanks for this thread. I have the EXACT same problem with the 828MkII, so it's most likely an 8pre issue. The ADAT clock solution sounds like it should work, I'll have to give it a try.

fazmanicg · Post by **fazmanicg** » Thu Mar 13, 2008 2:56 am

No Problem Feste. It's been 2 days now and it has been rock solid! Hope it works for you.