828mk3 hybrid issue.. white noise bursts on adat.

[L8N]

I have an 828 and connected to that I have 2 8pre's. One on each adat input (obviously).
The issue I have is on adat B I get short bursts of white noise coming thru each channel in succession, 1 thru 8. being i have it set up as 4 stereo pairs is seems to bounce from left to right. The level of this noise is around -40dB so quite audible.
The thing is, it doesn't matter which 8pre is plugged into adat B, therefor I can assume it's not an issue with either of those units and with the 828 itself.
The sample rate is set the same for all three units (48k) and if I change one of them it makes a hell of a racket as most of you have prob experienced.
Anyone seen this before? They are basically brand new units and have done this since I first plugged them in. I have created a Techlink with Motu and after 3 weeks it hasn't even been read! Pretty hopeless really.
Anyway, hopefully one of you knows of a solution for this.

Thanks!

[NazRat]

Could be a clocking issue. Are the 8Pres clocked to the 828mk3? If not, try that - you'll need to connect both the I/O optical on the 8Pres and clock to 1X optical.

[L8N]

I had considered this, and even connected the offending adat B with another fibre optic cable from the output of the 828 to the input of the 8pre. However, this did not seem to fix the issue, I may try it again to be sure tho. Funny tho how it's only adat B that faults, seems strange that the same setup would not work/not work for both adat systems.
Also, I have connected all 3 devices to the PC individually and made sure the settings for each are correct. Didn't solve anything either..
Thanks for the reply, any more ideas??

[L8N]

Ok, I tried connecting another lightpipe from the 828 output to the 8pre input and then selected Optical in X1 on the 8pre. After doing so the 8pre automatically selected 48Khz (which is correct) however, the noise bursts are still present.
One interesting thing to note, if I select 96Khz on the 8pre the noise bursts double in speed but halve in quantity due to the lightpipe one being capable of 4 channels at 96k.
So, not resolved unfortunately and still no response to my techlink submitted on the MOTU website (it's now 4 weeks and is still labeled as Unread!!)

[NazRat]

Another thing you can try is to clock the 828mk3 to one of the optical ports. That shouldn't be necessary, but maybe the 828mk3 is having a problem with it's internal clock syncing. You'd only need the one way ADAT connections.

[L8N]

NazRat: Thanks for the idea, tried it and to no avail, still the same bursts of white noise
Is there anyone out there that has 2 8pre's connected to an 828? I assume this is not happening to you? Maybe if you only have one 8pre you could try connecting it to the ADAT B instead of A to see if you can recreate the issue I'm having?
Thanks.

[L8N]

Anybody??

[timbirr]

Can't believe I couldn't find this forum earlier, I am having THE EXACT SAME ISSUE! I also posted a thread on here about this a couple days ago. The ONLY difference in our problem is that I am using 2 behringer ada8000 adat units, but at least this allows us to narrow it down to being an issue with the 828mk3. This is Quite possibly the most frustrating technical issue I have ever dealt with. Ok, the two of us need to smash our brains together and figure this out! Have you tried doing a wordclock from adat A to B? or MOTU to adat? I just ordered three wordclock cables, and I am desperately hoping that it will make a difference. I figured it might have something to do with how you can only set the clock source to A OR B, not both. But if we could wordclock A to B, set A as a wordclock slave, then set the source to B in the motu settings, maybe that would work... The ONLY other thing I can think of is that maybe our computer's processors and/or harddrives are too slow for 16 tracks, but as you've previously stated, it wasn't happening before... why would it start now? I have an HP Pavilion Dv7 with an Athalon dualcore 2.4ghz, 4g RAM, 1TB 7200rpm internal and external HDs, motu 828mk3 connected with firewire 800. Whats your setup? One person suggested removing the power conditioner from the loop, no good. Funny (not really), I'm actually sitting here listening to the tsst tsst tsst tsst tsst tsst sound right now.

[timbirr]

HEY!!!!

http://www.motunation.com/forum/viewtop ... =2&t=16560" onclick="window.open(this.href);return false;

I'm about to try this! God I hope this works for us!!!!!!!!!

[timbirr]

nope. No good. on to something else.....

[timbirr]

Got it. run lightpipe cables to AND from the main motu interface (whichever is going to be the master, connected to PC), make sure adat ins and outputs are assign in the motu settings, assign other adat units as Slaves. two 8 channel units will require 4 cables (2 light cables per unit). I suppose better ventilation wont hurt either, but won't solve the problem. Doing all of this got rid of my rhythmic white noise, hope it works for you!

[L8N]

@timbirr

Dude, sorry! Had basically given up on checking this as I was not getting anywhere with it! Great to see you have had success, I'll be giving this a go asap and will post results