USB 302 Behringer Xenyx interface was replaced with a Shure SCM410 where channel 1 and 2 were mod on circuit board for line in (ie CD audio). The USB 302 had significant issue with latency and 302 device Analogue mode was had greater noise to signal due to grounding issue. The Shure SCM410 accepts a standard IEC power cable with proper grounding.
I tested with ATSC on, ATSC off, and with Shure SCM410 off. There is noise what seems to come from the Shure SCM410 in the lower frequency range, ELF and ULF levels (0 to ~200hz):
I also am running the scope software now on OS/2 (ArcaOS) which has less latency issues and no slow downs of continuous uptime with OS/2. Linux with WineHQ had latency issue and eventually the scope would go to a snail speed of change. Running the scope software in Windows XP was not fully tested except for the Laptop running XP had grounding issues.
Initial test results:
Circuit change photo by prior owner of the Shure audio interface: