We're studying BJT amplifiers, and the project that I've chosen to do is to get my Ipod to to play on my music system speakers. The idea is to amplify the output signal from the ipod using a biasing circuit and transistor amplifier and use it as input for the pair of speakers. Ill most probably be using ac power, so I'll also need to make a bridge rectifier circuit (with a capacitor filter) to get DC to run the amplifier circuit. The thing is, I dont know what conventions are used in the audio industry, so I dont know what the ratings mean. I know that the headphones we normally use are rated for 32 ohms impedence, and the speakers I want to connect them to are rated at 8 ohms. Im guessing here that I need the amplitude of the amplified signal to be 4 times greater than the input signal from the Ipod. For the biasing, Ill probably be using a Voltage divider biasing ckt, but I cant work out the values unless I know what these ratings mean. Any hints, ideas?