Easy fix 240v - 12v dc
Sorry to dig this back up. I have used a pair of old power supply units from a pc to power an amp, seems to work ok, you dont quite get full capacity because you on 12v not 14.4. But it's cheap [free for me] and it works.
Just to tack a question on this one, how would you attach a power cap into the circuit. In a car it's no problem because it is perminantley connected to the battery, with an input that gets switched off, when you switch on it would try to draw too much from the supply all in one go.