I want to use my ipod on a small boat, I don't want CD or Radio, so I don't really want to buy a marine head unit. I have seen a waterproof amp around with headphone socket input and a separate volume control but no one has any stock. If I buy a 12v two channel amp as used in cars, can I connect the headphone output from the Ipod directly to the amp or do I need a pre amp? How do I specify the inputs I need? The unit will be protected from the water so I don't need a waterproof amp. Any help gratefully accepted, thanks