On 07/08/2012 21:37, Guv Bob wrote:
Another question.... I have a radio that shows a 9VDC input. Would
an adapter with 12VDC output work?


Too high a supply voltage (Volts, V), smoke from the apppliance.
Too high a demand for current (Amps, A), smoke from a puny adaptor.

Find a 9V DC adaptor that will supply at least the rated current the
appliance requires. Given that this may vary dependant on the volume the
radio is played at, and you don't know the radio's design limits for
max/min input voltage - best choose a adaptor that has a built in
voltage regulator (as suggested by gregz). Normally this is stated on
the case.

--
Adrian C