Emu XL-7 & MP-7 User's Group

Anybody else noticed this?  Up until I upgraded the OS I have had my 
XL7 connected via SPDIF to my digital mixer.  Every once in a while 
I would here a loud click/pop over my monitors from the XL7.  I 
thought it was a clock sync issue.  However, since upgrading to the 
new OS I have been exclusively using the XL7 with headphones (keeps 
my legs warm while sitting on the bed).  Sony MDR-7506 Pros to be 
exact.  Anyway, I am still hearing the pop/click ... OK so only 
twice in the last few days.  Definitely not as frequently as 
before ... but still there.
Justin.