888 interface's s/pdif input doesn't like AMIII s/pdif output

[jmark]

I picked up one of those $199 Toolbox xp deals, in part because I figured I could squeeze some more life out of my old NuBus TDM hardware using the new system for all the (24-bit) file playback, and using the old system (with the 24-bit mixer) as just a glorified "mastering processor", feeding through both the digital ins and outs in 24 bit, and using a Waves L2 box as the 24-16-bit conversion (and also as a very nice A-D convertor going into the AM3). Connection from the AM3 to the 888 is with a decent-quality proper 75-ohm cable.

First off, having been "frozen" at Pro Tools 4.2 for the last three years on my old NuBus hardware, it's great to see how the Pro Tools software has evolved. Lots of little things that always annoyed me are now fixed, and the added touches are really nice (love that "tab-to-transient" function).

The problem is that with the two sytems connected this way, various operations in Pro Tools LE on the AM3 card seem to screw up the 888's s/pdif input...things like bypassing/changing plug-ins, or even sometimes just changing a plug-in setting or stopping/starting playback cause the 888 to lose the signal (the "digital" indicator starts flashing, and audio cuts out)....in this situation, the only way I've been able to get signal back is by toggling hardware setup to AES input, closing out of hardware setup, then reopening hw setup and re-selecting s/pdif in. Making this especially annoying is that after about the fourth such "toggle", Pro Tools 4.2 goes into an "endless tapping fingers" hang.

Running other stuff like CD audio and a DAT machine into my 888's s/pdif input has always been trouble-free: I never saw the input become "unlocked" with a signal coming in until I got the AM3.

I "fixed" the problem by getting a 75-to-110 ohm transformer/adaptor, and sending the AM3 signal through that into the 888's AES input...connected that way, operation has been fine.

I'd rather be able to use the 888's s/pdif in for this, though, as it would reduce the need for back-of-the-rack cable swapping...anyone have any insights here?

[DigiTechSupt]

I think it is pretty safe to say that this configuration has been tried by many people (that includes us in Tech Support), so I'm really not sure why this is happening.

The only thing that comes to mind is the S/PDIF comaptibility setting in Setups>Hardware>Other Options window for your AMIII and 888. Make sure that both of them are configured to the same setting...I would suggest using the "Other" option.

Brent

[jmark]

Thanks for the reply..."other" (not Tascam DA-30) is selected for the AM3, I don't think there's any such setting for the 888 Hardware Setup (at least, not in Pro Tools 4.2). Maybe an internal jumper on the 888?

[DigiTechSupt]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:<HR>Originally posted by jmark:
...I don't think there's any such setting for the 888 Hardware Setup (at least, not in Pro Tools 4.2). Maybe an internal jumper on the 888?<HR></BLOCKQUOTE>

-You are probably right...It is very possible the S/PDIF compatibility option did not come out until PT 4.3, I wasn't sure.

-No, there is no jumper setting for the S/PDIF or AES I/O for any of our interfaces.

Just to confirm your hardware settings on the NuBus system:
-Ch 1/2 format: S/PDIF
-Sync Mode: Digital

Brent

[jmark]

Yes, that was how it was set (until I did the transformer workaround).

My best guess at this point (assuming my 888's s/pdif input doesn't have a malfunction) is maybe some kind of ground-loop between the AM3 and the 888 that was broken by adding the transformer.