I manage to turn an old cassette tape to a guitar amp but the problem is that the rolling engine (i don't know what to call it other than this words) is runing and useless, i tried to cut it power wire but then i can't get any sound.
Is someone familiar with this & have any suggestions?
You can try to bypass the "rolling engine."

By that I mean finding where the connections enter and where they leave, disconnect them and solder them together (bypassing the mechanisms).

No guarentee it would work, but if it doesn't it's easily reversible.

I don't believe in signatures. Ah, sh...