WC issues - 2408mk3, PSX-100, and Big Ben at 96K

[Mark Williams]

Hi,

I just upgraded to a new(er) Mac Pro (5,1) and got the idea to take the older 2006 (1,1) Mac Pro and make it into a dedicated 96K/24bit two track recorder. I have a few surplus items to use, including a 2408 Mk3/PCIe-424, an Apogee PSX-100 ADDA, and a Big Ben to clock the whole mess. The software is an older version (6.0) of Cubase. Normally I mix to analog tape and then transfer back into numbers for a digital master, and I thought it might be cool to step up my deliverables to 96K using this rig.

So the Big Ben is feeding WC to the PSX with 75ohm termination, separately to the 2408 mk3 with no termination, and the PSX-100 is using SPDIF for both sends and returns to the 2408 mk3. The PSX has been modded by Apogee for 96K single wire through AES, SPDIF, and Optical.

Seems like it should work, but I'm getting clock pops in the output. I can see them on the MOTU's meters. This is disappointing! Anybody got any ideas? Thank you in advance.

[Mark Williams]

Well, the problem may have been solved and in an obvious way.

In the installation, I had opted to use a shorter FW cable to connect the PCIe-424 to the 2408mk3. Usually shorter is better for data, right? Apparently not this time because when I redid the hookup with the long cable that came with the MOTU stuff originally, the clocking issues seem to have disappeared. Cool!

Perhaps there is something amiss with the FW cable or perhaps there is some property in the MOTU cable that is essential, but the bottom line is that it is working. If anyone wishes to weigh in on what this property may be I would be glad to know about it, thanks.

[Mark Williams]

AND… a few more glitches came back. Maybe I'm asking too much of a 2408mk3 but Ihave confidence in MOTU hardware. The clock glitches seem to come from the 2408, just showing up visually on a green LED and of course audibly via the SPDIF.

[mikehalloran]

when I redid the hookup with the long cable that came with the MOTU stuff originally, the clocking issues seem to have disappeared. Cool!

Perhaps there is something amiss with the FW cable or perhaps there is some property in the MOTU cable that is essential, but the bottom line is that it is working. If anyone wishes to weigh in on what this property may be I would be glad to know about it, thanks.

That's not your imagination -- the long cable is not a FW cable. These pre-dated FireWire.

A close examination of the two will show that the connectors on the MOTU data cable are longer. A little trimming of the insulation at the end of a FireWire cable with a thin, sharp blade will generally make it work.

[Mark Williams]

Thanks, that's good to know about the cable.

At this point, the system is quite stabile at 48K but the 2408mk3 is glitchy coming out SPDIF at 96K. Set up for SPDIF out only at 96K, I can see audio indicating on Bank C #1 output LED and occasionally #3 will flicker along with big clocking pops. The WC cables are all professional 24" 75 Ohm BNC types.

The point was to have this as a dedicated 96K stereo recorder, so I'm about to look for a plan B. Before I bail on the 2408mk3, has anyone got any thoughts about how to stabilize this rig?

Thanks for your thoughts!

Mark

[mikehalloran]

How current are the drivers?

If you're running the latest, try installing the ones that were current for your OS. If you scroll down, you should find them.