Hi Friends,
I have already put a post on another forum, but just in case it will not be seen, I'll post it here as well. Many of these sound issues can be easily fixed with a little Isopropyl alcohol or other contact cleaner.
Unplug all of your cords and power supply, and dip that swab into the alcohol/contact cleaner and then clean out all of your input and output 1/4" jacks. Give it a couple of minutes to dry and plug her back in and see if this alleviates your sound problems. I don't know how many times this little trick has saved me tons of money and valuable time chasing down other "fixes" when this was all it was. Dirty input/output jacks!!!
Let me know if this helps any of you out :-)
Art