That sounds about right. I do know that most of these systems are starving for power, hence the distortion as you turn them up. It wouldn't hurt to have a 50W amp pushing these 35 W speakers. Just be careful and be sensible. As long as it sounds good and clear, they are fine.It will be on the label on the back of the speaker magnet. I believe the early 1500's had 25w speakers and then the later models were upped to 30w or 35w but not sure what model year. Speakers should be 4 ohms as well I think.