That a hundred and fifty five watts likely refers to the highest amount of power the receiver takes from the AC line, due the fact that it is stamped on the again and the receivers of that time hardly ever indicated the output vigor there. It is a conservative rating, used for picking out how many things one could plug into the same outlet with out blowing a fuse, and the receiver will will doubtless on no account eat this a lot vigour at all times. This number has a very loose relationship to the exact quantity of energy it's going to put out to the speakers. My wager is that the receiver is frequently rated somewhere in the 30 watts per channel variety. 30x2channels(stereo) is 60 watts. If you happen to hook up two units of audio system this may increasingly relatively less than double to like a hundred watts, and then aspect within the amplifier is not 100% effective at transfering AC line energy to speaker energy, some vigor is used for the tuner, and that you can come to be with a hundred and fifty five watts. The first-rate thing to do is to Google the mannequin number and discover how a lot it honestly is.