Hi I received a brand new spider III 75 Watts 1X12. with a FBV shortboard as a gift.  I am having feedback problems with certain patches.

Ex CliffsoDover.  I get a feedback loop in A even if I turn off the volume on my guitar.  It just keeps goping till I chnage to a clean patch.. I also get the problem on Leadorama patch.   It's not my guitars, I play parker fly deluxes.  These guitars have never let me down,  It's not my cordless unit,  It does the same thing if I I'm wired.  Volume wise,  I never go past 11 o'clock on the Master Volume.  I have even cut back on the channel volume.  Anyone can give me a suggestion?