[LAU] Problem with Lexicon Omega USB-Audio device

[Susanne Schneider]

hello list,

when plugging in my LexiconOmegaStudio USB-Audio/Midi Interface to my 
Laptop (Asus A4K, Mobile Athlon 64 1.7Ghz, 512 MB),
dmesg tells this:
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usb 2-1: new full speed USB device using ohci_hcd and address 3
usb 2-1: new device found, idVendor=1210, idProduct=0002
usb 2-1: new device strings: Mfr=1, Product=2, SerialNumber=7
usb 2-1: Product: Lexicon Omega
usb 2-1: Manufacturer: Lexicon
usb 2-1: SerialNumber: Lex1.00
usb 2-1: configuration #1 chosen from 1 choice
ALSA sound/usb/usbaudio.c:1263: 3:1:1: cannot get freq at ep 0x1
ALSA sound/usb/usbaudio.c:1263: 3:1:2: cannot get freq at ep 0x1
ALSA sound/usb/usbaudio.c:1263: 3:2:1: cannot get freq at ep 0x83
ALSA sound/usb/usbaudio.c:1263: 3:2:2: cannot get freq at ep 0x83
ALSA sound/usb/usbaudio.c:1263: 3:4:1: cannot get freq at ep 0x2
ALSA sound/usb/usbaudio.c:1263: 3:4:2: cannot get freq at ep 0x2
ALSA sound/usb/usbaudio.c:1263: 3:5:1: cannot get freq at ep 0x85
ALSA sound/usb/usbaudio.c:1263: 3:5:2: cannot get freq at ep 0x85
ALSA sound/usb/usbaudio.c:1263: 3:9:1: cannot get freq at ep 0x1
ALSA sound/usb/usbaudio.c:1263: 3:9:2: cannot get freq at ep 0x1
ALSA sound/usb/usbaudio.c:1263: 3:10:1: cannot get freq at ep 0x83
ALSA sound/usb/usbaudio.c:1263: 3:10:2: cannot get freq at ep 0x83
susanne at linux-s:~>
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using two of four possible inputs with jack I'm able to run my standard 
apps like Ardour, Rosegarden, Hydrogen, Bristol, Qsynth with a minimal 
latency of 128 Frames/Period and 4 Periods/Buffer at 44100 Hz (=11,6 ms) 
without xruns -
BUT(!): sometimes (seems to depend on the extend of use of plugins and 
synths), during recording after some minutes from the start an 
increasing crackling-noise occurs which makes my record unusable - jack 
reports no xruns at all!
I then have to stop and close my apps, restart jack and start all new... 
a tedious biz...
Searching the Internet I learned that my Audiocard may not be 
"devicecompliant" in terms of USB - whatever this means.

What my question is to the list:
is there any experience yet with a firewire device like Edirol FA-66 and 
Freebob in terms of stability? Could I have a chance to come to a better 
and more stable performance by using Firewire rather than USB?
best regards and thanks for any hints,
Susanne