When I record songs, I go from my guitar to the amp. Then I get an 1/8-1/4 inch adapter and go from my amp right into garageband on my lappy. Just earlier I wanted louder speakers so I got the 1/8-1/4 adapter and went from the mactop to the amp. Will this blow my amp or screw it up in any way? I was listening to Sublime and it had a lot of bass so It got me thinking.
You've got the wrong forum. I think it will be ok though if you go from the headphone jack to your computer, but otherwise no, I wouldn't try it with my own gear.
As long as it's not a tube amp. Having a tube amp on without it being plugged into a speaker cab will **** it up (not applicable if it's a combo, but it still must be attached to it's speaker).