I recently bought a CAD C9 small diaphragm condenser microphone (Cardioid). I mainly bought it to record my acoustic guitar into a looping pedal, or to possibly record into a computer or phone (I know that wont produce the best sound, but that is not a big concern of mine). I am defiantly not doing anything major or professional, I just got it to goof around with my looping pedal and maybe record a few things. The problem I am running into is I get a massive amount feedback from my amp. I am very new to this and not well versed in most of the microphone, and preamp basics.
Here are the details of my set up/chain:
CAD C9 Carioid condenser microphone, into
Tube Microphone preamplifier (ART Tube MP Studio)
Boss R-3 Looping pedal
Behringer noise reducer pedal
Line 6 Spider IV 15 amp

I was wondering how to set/position my microphone and preamp to reduce the loud feedback I get from the amp. The only way I have found to eliminate the feedback is to have it turned down so low that it is hard to hear the guitar.
I would also appreciate any other comments or suggestions to my set up that would improve it.