Clock help needed

[MVE]

I have an ancient motu 828 (gen 1).

I have used it since 2002. It works and sounds great.

I just got a second one.

I have then both individually plugged in via FW.

But there have been some clicks and pops.

Is this a clock problem? Do I need an external clock?

 

[silky smoove]

It could be a word clock problem but that’s not the first thing I would consider. My first thought would be buffer size. Regardless, the gen 1 828 doesn’t have a BNC connector which is how you typically connect to an external word clock. There may be external optical solutions but I’ve never looked for one.

Is there a reason you’re connecting both interfaces via FW? If the second interface is only providing additional preamps you could connect it to the first via ADAT which would sync the second unit’s word clock to the first’s.

 

[MVE]

It could be a word clock problem but that’s not the first thing I would consider. My first thought would be buffer size. Regardless, the gen 1 828 doesn’t have a BNC connector which is how you typically connect to an external word clock. There may be external optical solutions but I’ve never looked for one.

Is there a reason you’re connecting both interfaces via FW? If the second interface is only providing additional preamps you could connect it to the first via ADAT which would sync the second unit’s word clock to the first’s.

Thanks.
I’ll try increasing the buffer.
I tried using only one FW with the optical but it didn’t seem to work.
Is a single FW preferred?

 

[Tosh]

I got a peek at the rear panel of this unit - it supports ADAT sync on a 9pin (RS232) input (no output)
It also has ADAT (or S/PDIF) optical in + out, and COAX S/PDIF in + out. There's no FW output, so you can't link them together on the same FW host bus. This is most likely the cause of the problem. In theory, you should be able to link the units on a TOSLINK cable, set unit B to be the clock master, set unit A to sync to unit B, and set the PC to sync to external (unit A). For the Mk1, I'm looking at that ADAT sync port and thinking - this might be a solution. If you can, try the 9pin to link the units together and see if they will sync up.

possibly helpful info:
Link Removed

 

[hbarcat]

I'm pretty sure the clicks and pops are indeed caused by a lack of clock sync.

According to the owners manual, when using 2 of these units simultaneously, you'll need to sync one to the other. In the audio settings menu, set one unit to master and the other to slave. Connect the units with optical cable, master out to slave in.

Manuals | MOTU.com

 

[Tosh]

Thanks for that link - pg 19 discusses sync setups

the ADAT SYNC port is only used for syncing to ADAT tape - not required for light pipe connections between 2 828's.

In my experience, you need high quality TOSLINK cables for reliable sync. Those thin ones that work OK with stereo don't work well with ADAT.

 

[MVE]

Well I plugged in both of the optic cables, in to out for both, and turned the opticals for both units ON and on ADAT.

Master clock is set to 828#1 Internal and 828#2 is set to Master Clock.?.?.? (I tried ADAT but then clock light just flashed and unit 2 didn’t work.)

Both FWs are still plugged in and “I think” that’s where is coming in.

Fingers crossed, but I haven’t heard and pauses in a while, so maybe they are syncing via the fibers.

I have’t changed buffer yet, but will try that next if stutter comes. Its already pretty high on 512, but I don’t live monitor anything digital, so latency doesn’t bother me.

Thanks all for your help.

My old 828 has served me well for 20 years now and I just got the second one for $25. I was excited to go from 8 to 16 channels, but Im going to have to pull it if I can’t figure this stutter thing out.

 

[Tosh]

you don't want to have both FW ports connected - just one. If unit B is the far end of the chain, then it should not have a FW cable. It should be able to sync to the ADAT link, where unit A is the clock master, and is the FW cable link to the PC (assuming all the hardware and cables are working correctly)

 

[fokof]

If you're on a Mac , just use both as Aggregated device , make one of them the master clock.

Should do.

 

[silky smoove]

The standard approach for expanding an interface via optical would be:

• Interface A to computer via FW
• Interface B ADAT out to Interface A ADAT in

That should get it done without needing to mess with additional cables or setting up aggregate devices, provided all you’re using Interface B for is its preamps.

 

[MVE]

The standard approach for expanding an interface via optical would be:

• Interface A to computer via FW
• Interface B ADAT out to Interface A ADAT in

That should get it done without needing to mess with additional cables or setting up aggregate devices, provided all you’re using Interface B for is its preamps.

I tried every possible option to connect without the second FW and I could not get it to work. I can see the inputs listed in the Daw but no audio is coming in.
It works with the two FWs but there is an occasional stutter.
I really only need the additional channels when tracking the drums, so my best workaround is to just shut #2 off unless drums are being tracked.
I am going to email MOTU and I will report back if they have any suggestions.
Thank you and thanks to everyone here for your responses and help.

 

[silky smoove]

Rather than emailing you should try their product support page. It has an internal messaging system and I often get responses from it within a couple hours.

 

[fokof]

2:30