Here is the circuit diagram of the classic 5W Tube Amplifier with EL84 as the final amplification component. This is a single channel amplifier (mono) of course with single input and single output. You should build the two similar circuit to make it stereo.
The power supply design diagram already provided on above tube amplifier circuit diagram. Please be careful during constuction, it need enough experience and please pay attention the high voltage in all section of the circuit, electric shock danger!