OK, I'm just looking for some opinions out there. I'm recording guitar into Logic, mainly sitting at the computer and getting my sounds using a Guitar Rig 4 plugin. I'd like to take my raw recordings and do some re-amping (since I have an Orange Tiny Terror amp, that sounds great but I can't really run at full recording volume in my house). My plan is to use my MacBook, USB interface and re-amp through the TinyTerror, recording the speaker back using an SM57. Latency doesn't worry me, as I can fix timing later. My question is... should I use a re-amping box with a transformer to hook my audio interface back into the guitar amp? Collective wisdom on the 'net seems to think that I should get a re-amp box, but I can't see why. My audio interface outputs a perfectly good unbalanced signal, I can turn it down to guitar levels and I shouldn't get ground loops, 'cos the MacBook will be on battery. Any comments?