I've heard rumors that word clock "doesn't work" on the M-Audio Delta 1010s. Can anyone confirm/deny this, or point me to some more definitive data? Is/was this a software/hardware/both problem? Generally I've found the Delta card software _says_ it has sync, but in listening to the audio there are lots of pops and crackling noises. So extended critical listening is in order to make sure things are indeed synced.
I'm trying to sync a rather complicated system and I'm having lots of sync problems. I'm about to spend some serious money for a master word clock generator, but not if the 1010's can't properly deal with word clock anyway.
I have observed the following with the 1010s:
(1) If synced to external word clock, 1010s will not recognize a valid SPDIF input stream, even if word clock and SPDIF are coming from the same source (a Presonus Digimax 96k in my case). If you want to input SPDIF audio, you must clock from it also.
(2) According to the M-Audio manual, the 1010 can send word clock up to 96K, but can only read word clock to 50K. Not a big deal for me fortunately.
(3) Also from the M-Audio manual, the 1010's word clock input is terminated internally, and there's no way to disable termination. This means you must "daisy chain" 1010s in the word clock stream, and you can't run a "star" network using BNC tees and external terminators. I've seen opinions both ways on the best way to route word clock, but I can't even try the "star" topology unless I get a master word clock generator with multiple outputs.
(4) The latest M-Audio delta driver as of this writing (22.214.171.12451) resets its buffer size to 64 bytes (the minimum) when I load VST instruments in some applications. My system can't handle 64-byte buffers so it stutters and locks up, requiring a reboot. The previous driver version (5.10.0.0048a) did not have this problem.
Any help would be appreciated.
P.S. Come to think of it, I've never seen any technical specs on word clock in general. Are there any "official" specs on rise/fall time, voltage swing, under/overshoot/noise margins, etc? My guess is no; it's just whatever nominal square wave any given manufacturer wants to call "word clock". If there were some specs, I could look at the signal on my oscilloscope and tell if the my jitter/skew was within acceptable limits.