What in the world do you need an amplifier for a motor?!?
Motors don't use amplifiers, they don't need them. Please explain this because I don't at all understand what you are talking about.
.....Let me expand on this. You implied last night that you want to use a power transistor for an amplifier, but not for music, for a motor. OK, let me explain why this doesn't make sense. Amplifiers are used to increase a signal from a small level to a greater one. For instance, the induced voltage from the voice coil in a microphone is a very low voltage AC, which isn't strong enough to drive a speaker, so we amplify it to stronger power levels to satisfy the requirements of the speaker coil. In the case of a motor, the only requirement to drive the motor is that we supply the proper voltage that it is rated for. If the motor is a 12 volt DC brushmotor, all we need to do is apply 12 volt DC to the 2 terminals of the motor, and it will turn, no need for "amplification", because there is no variation in signal. All you need is the proper power supply. Now, having said all of this, transistors can be used in a motor control circuit, but they are not being used as "amplifiers" per say. Rather, they are being used as switches. If you are building a logic circuit that will control a motor, say, to turn it on when a certain event occurs like a mechanical switch closing or a timer circuit activation, you might need a transistor to relay the event signal to the motor. But again, this is not really an amplifier circuit, but rather a switching circuit. Now, you indicated a need for 1000 watts, and I am assuming this is for the motor. This indicates to me that you are wanting to drive an AC motor, because DC motors are seldom 1000 watts! In this case, a transistor IS NOT the correct device to drive the motor! I would recommend some solid state relay, triac, or mechanical relay configuration.