Okay so i have to play a show that requires me to play samples through my amp and use pod farm as my preamp but for some reason im getting insane feedback when i play. Current signal chain is:
Gibson sg
Tone port ux2(macbook pro, ((noise suppressor, tube screamer, criminal, compressor, reverb)))
Crate shockwave via toneports monitor out r1 in to line in to bypass the amps pre
Crate blue voodoo 4x12 cab with specialy designed eminence via speaker cable.

The tone ports output knob controls the volume to the power amp but at a good show volume feedback is crucial. Kicks in after 3 seconds of holdind a chord.

Is this the best way to do this with out going directly in to the p.a.?
How do i kill the feedback with out losing gain and volume?