You could use the switched side of the fuse panel. On when the car is on and off when tha car is switched off. No need to get overly technical . It's not like the trigger line actually draws a current, it Just senses 12v and says wake up amp. You could fit a switch to it so you can switch it off while driving if you desired as well.

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You can get a low voltage trigger which you plug into the rca input from the ipod and gives you a remote signal when it recieves a signal this means that it will turn the amps on and off whenever you plug your ipod in

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I'm grew up on the street, not the hood, the sesame st

thanks for all the good words guys...
i had always thought it was a 'simple' but conceivable concept,
but like everything, if not thought through could look absolutely shite!?

the comments about turning amp on/off, self-powering amp etc
all make great sense, and i'll definitely look into each of these ideas.

last note, for those still interested
after a long search for a decent dock or holder etc
i thinking bout using/modifying one of these.....

http://www.just-mobileonline.com/produc ... ies_1.html

what do you think??
possibly modify it to mount to the underside of the dash.....
concealed wiring running discreetly under the dash,
and the bonus of portrait and landscape.

or possibly between the front seats, near handbrake...??
in any case....somewhere!

I have been running this setup for 3 years now. Ipod to Amp to speakers. Volume controlled by ipod. Amp has a volume control you can set as well so you don't blow the speakers.
Power mains direct from battery, with a "sender" feed from the ancillaries circuit. to turn amp on and off.
I thought i may have had issues with the power surge you get when you plug in your ipod, but it hasn;t damaged anything yet.
Simple system, sound great and sadly probably louder than the next door neighbors ricer stereo

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This shouldn't really be an issue as most amps will accept a trigger from the Head Unit to turn them on, and subsequently off if you turn the Head unit off. Running a 12v feed from ignition/accessory would be a similar trigger, thus turning the amp off when the ignition is off.

Dicko