Can you identify this Bose car amp burned part?
Do you mean 24V supply during jumpstart? In this case, I suspect the blown part to be a 18V transient voltage suppressor diode. It tries to "short out" voltage in excess of 18V and reverse voltages to protect the electonic behind it. Just removing it should make the amplifier work, but without protection. If it doesn't work with that part removed, there is more damage. If it does, get a new TVS (for example the Littlefuse P6KE18A).

If the voltage was applied in reverse direction, it might be a standard diode, instead of a TVS. Both diodes and (unidirectional) TVS try to kill negative voltage by having a very low impedance (like a short circuit). They loose the fight (diode pulls the voltage down, battery pulls it up) against a car battery in less than a second, and typically get a hard short circuit, which will kill a fuse before the TVS/diode.