Can I go from an 828mkII to an 8M?

[RodneySauer]

So, I have an old 828mkII that I replaced with an 8M for my recording studio. I usually use 8 channels, so the 8M is adequate.

I have a project coming up where I may need to add six more channels. So, I'd like to bring the 828mkII back online, but am looking for how to get its audio to my newer Macbook (which uses Thunderbolt/USB4).

With a bunch of adapters, I may be able to go from the 828mkII to USB4. So it would be entirely parallel but separate from the 8M.

But I'm wondering if I can feed the digital output of the 828mkII into the digital inputs of the 8M, and not require another USB4 port and cable, which I'd have to run through a wall.

According to the data page, the 828mkII has digital outs:
8 (channels) ADAT 1 x S/PDIF RCA coaxial. I've never used it.

The 8M tech sheet gives Digital I/O as:
2 banks (16 ch) of ADAT optical at 1x sample rates
1 bank (8 ch) of SMUX optical at 2x sample rates
Stereo TOSLink (optical S/PDIF) on Bank A

Are the ADAT optical connectors described here for the 828 and the 8M the same?

If not, is there a cable that will connect these two?

[CharlzS]

Yes. You can use Cuemix on the 828mkII to set up routing, look here: https://motu.com/techsupport/technotes/ ... 7968752604. You can dial all that in, but way easier to use Cuemix if you have another computer you can use. The ADAT connectors are the same. Since the 828 only has one set of ADAT ports you can have 8 channels @ 44.1/48k or 4 @ 88.2/96k. You would use standard optical audio cables (plenty on Amazon). I've used the 828 this way without issue.

[RodneySauer]

Thanks! I'll give it a shot.

[mikehalloran]

As long as everything is set the same such as 48kHz/24bit, you might get away with a single optical cable with the 828mkII at the end. With only two devices, external clock should not be needed (that is not a guarantee, however), most don't need one. I used to do this with my 828mkII and an ancient 2408/324 without drift.

Otherwise, you would set up an Aggregate Device in the MacOS using two ports. The 8M cannot be in the middle of daisy-chain—In through TB/out through USB. Although you could use the 828mkII in the middle with enough adapters, there's no getting around the data speed being FW400 in the middle—so only try that if desperate for free ports.

MOTU's 8M manual cautions against using more than two ports. Other MOTU manuals say to plan on using an external clock if using three oe more units.

[RodneySauer]

The 48kHz 24 bit should be fine. Now I need to dig up that snake I used to use to run the preamped-channels from a Mackie Onyx mixer to the 828... and find the extra microphones I'll need. But the session isn't for months, so I've got time.

As I recall, the audio-over-ethernet-cable that the 8M supports hasn't been as reliable as once was hoped, but that would probably also simplify some of this.

[rockitcity]

If you haven't done this already, it's actually pretty simple if you follow the routing in CharlZS link. I happened to have done this today as my old 8Pre just suddenly quit and I had an 828 MkII Firewire interface sitting around from a previous installation to replace it. You really only need to run the ADAT optical cable from the 828 to the 8M, set the routing as in the link (I figured this out before I saw the MOTU Tech note, but did it all from the front panel of the 828.) You need to run a BNC cable from word clock out of the 8M to word clock in of the 828 and sets its clock source to "word." This way, if you change the sample rate in your DAW software, the 828 will follow along with the 8M.

No need to use the FIrewire connection on the 828, but it would simplify the routing as per the tech note. The 828 should just show up as additional ADAT inputs. in your software.

Hope that helps!

[HCMarkus]

I am always inclined to favor Word Clock when available..

[mothra]

One thing to remember when it comes to the MKII, you don't have enough CueMix 'slots' to do both 8 in and out at the same time, it's one or the other, or a mix of a few channels in and out.

With the older MK2, you only get 4 CueMix setups, so the first one will be Analog 1/2 into ADAT 1/2, second one is Analog 3/4 into ADAT 3/4, etc.. Or vice versa. Not sure about the MK3, but when they got to the X, it's got enough CueMix setups to do both at once.

[rockitcity]

May be true, but since you are using the 828 MklI as an expander, it's a set and forget situation. Don't think you would need to run it as an A-D and D-A convertor both at the same time. This scenario would be for additional analog inputs into your existing system, and is quite transparent. Only 2 additional mic inputs though.