12v Conversion For 240v Equipment

[2412electrics]

As a basic idea most electronic equipment can run from a twelve volt supply.Or that there is equipment that can run on either power source. My question is " how difficult could it be to build a conversion power board so audio/visual equipment will work from a 12( Twelve ) volt supply"? my reason for asking is that I work heavily in alternative energy formats . It makes no sence ,at least to me , to fit an alternative supply at 12v then have to use something to boost it up to 240v so equipment can be used.
what happens to create the 240v supply is we have to swap amps (or our resevoir of energy in batterys) to make volts . This to me creates basically aloss in gain.I.E. what you have gained in alternative energy is lost by putting extra strain on the system thereby its lifetime is lessoned .so any ideas circuit/component diagrams advice etc would be gratefully appreciated.
and nice site .haven't had time for a goood look around yet but will get to it soon.

[Electro]

Converting 12 volts to a higher voltage creates noise. Noise is created by the switching regulator. A standard linear regulator can not create higher voltages.

It is possible to power AC equipment by a 12 volt DC source like a battery or fuel cell. The device that does this is an inverter.

There are amplifiers that can be powered by a 12 volt source and having an output power of 100 watts. Jam Tech has a amplifier that can hook up to a 12 volt source and it outputs about 50 watts. It uses a capacitor and inductor to literally pump the audio signal to a higher level in to a load instead of using a transistor for amplifying.

2412electrics, you should know that if the device is powered by a 12 volt source and it is consuming 5 amperes. The output if stepped up to a higher voltage such as 240 volts. The amperes will be 0.25 amps. However, this doesn't count for efficiency so it will be around 0.21 ampers with almost 20% lost from heat.