A C64 as a car audio system ?
Sounds like a good idea to me, and it has been done! Check it out !
quoting from another thread:
...I recall an edition of the German magazine 64er, in which they had a schematic
how to run a C64 on a car battery. They wanted a completely external solution
(And the 12V of a car circuit is too unreliable to use it directly, anyway),
so they went for a clever hack that gets the job done (But not as efficiently,
nicely as it should, but hey...)
What they did was generate a 9V DC square wave at 50 Hz (PAL country), feed
it to a transformer which started its life as a 220V primary, 2x9v secondary
transformer, carefully insulated the 220V primary coil, and fed the C64 off
the second secondary coil. Their idea was that this would make the square wave
look sinusoid and properly seperated from the 5V DC they created using a
conventional solution. I just don't want to know about any higher harmonics...