Ok, so I bought a used Ibanez S470DXQ guitar a while back. It's a great guitar at lower volumes, but when I start to crank it I get huge amounts of high squeeling feedback. I have done combinations with the volume and pickup knobs and I can get it to go away, but it really compromises the tone and sound I want.

I decided maybe new pickup would remedy this (Not to mention a heavier tone) so I installed a Duncan Invader pickup and still to no avail. Now I also have a Les Paul classic that give no feedback at all so I dont think it's an amp problem. And the other two pickups in the Ibanez give back no feedback either. So I'm at a loss as to what's wrong here.

Maybe The wiring is off and I wired it wrong? When installing the new pick up I simply followed what was already connected and soldered that way, but with the invader pickup there were two extra wires that the previous stock did not have. Those I just grounded with electrical tape and the pickup itself sounds fine.

Any help would be so appreciated. I've put a lot of time and money into this guy and I would love to get him playing live soon. Thanks. (In case it matters I play Metal/Rock)