In-Car Express wrote:

Switched (accessory) tells the unit when the vehicle ignition's
switched on, allowing the unit to switch on and off with the ignition.
This is usually a relatively low current feed.

Seems to be the other way around in my Fiesta (1995). The switched 12V
can supply a lot more current than the permanent 12V, which has the sole
purpose of supplying a memory backup voltage.

At a guess I'd say this is because all Fords of that era (with the
standard DIN aperture) disabled the radio completely when the ignition
is off. Newer types allow you to turn it on without the ignition, with a
timeout.

I've replaced the factory-fit unit in mine with a Sony MDX-CA580 and
offboard amps. When connected to the permanent 12V feed the drain caused
the car's illumination to dim when the volume was turned up! This
doesn't happen when it's connected to the switched 12V supply.

(I know ideally I should have the amp connected directly to the battery,
I just haven't got around to doing this yet. One day, perhaps.)

--
Glenn Richards Tel: (01453) 845735
Squirrel Solutions http://www.squirrel-net.co.uk/

"Growing old is compulsory. Growing UP is optional." -- Anon