Hi so I recently got a tascam 424 mkii and I've been using it a pot lately. Anyway, I have two tracks that have guitar feedback that I want to sample. How would I go about a) sampling the section so I can loop the part I want and b) isolating the guitar feedback so I don't hear the chords?

What I was considering doing was figuring out the feedback and recreating it on synth but idk if that will sound as good.
Green, can you explain the goal a little more? So you have two tracks with guitar feedback - do you mean like a stereo version of the same guitar feeding back?

By sampling, you mean you want to get this sound onto a computer and converted to a wave file or something? And then input it to an SVT plugin as a sound font maybe?

Also, do you want it so you hit the key on the keyboard and get the original attack (start of the sound) from the guitar, and then you hold the key down and it keeps the feedback sound going?
I'll try to. The two tracks aren't guitar feedback, they just have feedback "in" them if that makes sense. What I did was I took my spx90 and ran the stereo output into tracks 1 and 2 on the tascam, I also had a digitech digiverb in between track 2 and the spx90 so that it has a light gated-reverb effect in addition to the reverse. Then I played the guitar into that, I made sure for it to be really loud so that the bars on the recorder would be in the red no matter what while I'm playing. When I replay it, there is this ringing feedbacky-synthetic sound that I want to isolate and loop over a cleaner guitar.

I'm not sure if sampling is the right term necessarily, I only used it because it's the best way to explain it from my understanding of what sampling is. I have no idea what keyboards, attack or holding the key means.
OK, that helps me to understand. I get the sound you're after now, but I'm still not sure I understand about the sampling and looping. Do you want to get this sound into some other device that has the ability to loop stuff around? Or are you wanting to just keep repeating this section of sound on the Tascam and get the tascam to have a long repeat of this sound? (or something else?).
I'd like to get this into another device and then into the tascam so I can manipulate it a little bit more. What I was thinking of doing was increasing the higher eq then lowering the low eq, bouncing to 3 and 4, then do the same thing with the eq, then bounce back to 1/2, eq, repeat, etc. then plug the headphone out of the tascam into a looper pedal or something and then put it back into the tascam after I finish recording the guitar part that i want to keep.

It probably won't be able to get rid of all of the guitar sound, but it should get it so that the difference between the guitar and the feedback/harmonics is enough so that the guitar isn't as present in the mix.

I hope that makes sense.
Green_ghoul, OK, I'm getting a more clear idea of what you're after. I used to use a Tascam Porta 2 4-track back in the day. The one thing I'd recommend (probably not what you're wanting to hear) is that this kind of thing is an order of magnitude easier to do if you can digitize the sound snippet and then manipulate on a computer. It's possible to do the bouncing and such with a Tascam, but much harder. I've done things with copying a track to another device and then back to the Tascam (I used to do that to slow down guitar solos, then run through a pitch shifter in the end!). So what you're doing can probably work, if you get something cheap for a PC it will be very easy to edit, EQ, copy, blend, etc. Just a thought - I don't know what options you have available...