#1
hey guys, i have a spider III 120 and i was wondering if it was ok to plug the amp headphone jack into the computer to record some stuff? i know its not gonna be great quality, but i figure it will be something. i just wanna make sure before i do it, because im not sure if computers power stuff up, and i dont want it to ruin the amp. and also i have a integrated sound card, so im not sure if that makes a different, i still have a mic input.
Gear:

Ibanez RGT42DX
Boss MT-2
#2
honestly...i have no clue...but i have done what u asked...and it crash my computer...lol...so im guessing not...bc ur overloading ur computer with too much power behind ur sound...thats my theory...i have tested it lol...it doesnt ruin ur amp or nothing....it would most likely ruin ur computer...bc ur computer is on the receiving end of the current...hope this helped...
#3
It's fine, it will sound pretty bad, if it even works at all, with that integrated sound-card.
In fact, i'm not even sure it will record anything because of it.

Definitely won't damage your amp or the computer though.

It's best to use an amp out jack and plug it into an input signal jack (or use a mic and stick it into the input jack or phantom-powered jack) on a semi-pro card, ex. E-MU 1212M, 1010, 1820M, 1616M, Delta 44, 66, etc.
You'd get much better quality that way, and be able to select the hz you want, such as 44, 48, 96, etc.
2003 Schecter C-1+ w/ Seymour Duncan AHB-1 Blackouts
2006 Epiphone 66' Re-Issue SG
1980's USA Fender Stratocaster w/ 50's Gibson Humbucker
Fender Deluxe 112 Plus Amplifier
Vox Valvetronix AD15VT Amplifier
Peavey Basic 50 Amplifier
Pod XT Pro