When should I grow concerned about the amp clipping the speakers? I am happy with 40 wpc but I'm concerned that my speakers might not be. I read a few threads, not sure where, that suggested setting the volume to no higher than the 1 o'clock position to ensure undistorted power.
Neil, the speakers and the associated output circuit cause the amp to clip, not the other way around. The usual first victim is the tweeter or the high pass portion of the crossover. In rather extreme circumstances, smoke is released from the caps or resistors in the crossover. I should have video'd that, rather impressive chuffing smoke from the ports. Your ears have to tell you when the amp is oscillating. Your lower powered setup should make it pretty easy, as compared to club levels. Is it a 3020 you are using?
Be judicious with the volume and don't turn it up loud enough to distort. Where that is on your volume pot with your speakers is something your ears will have to determine.
Turn up the volume and you will hear the overall level rise in a consistent manner as you turn the vc. At some point the level of loudness stops and cannot rise above a certain level no matter how far you turn the vc. The sound becomes compressed and distorted. If your speakers are still working, turn the volume down. That's clipping and by the time you notice the level no longer rising, the amp is well into distortion levels that will damage a speaker. On a simple potentiometer type vc, clipping has set in on peaks at about 1-2 O'Clock on the control setting. That varies with the signal you feed the amp and the nature of the signal that drives the amp into clipping. Put "amplifier clipping" in a search engine.
I used to have that receiver many moons ago. It's not a powerful or particularly loud receiver but it suited my needs very well. Only thing that went wrong with it was the display lights....and often.
A little amplifier clipping isn't gonna cause immediate damage to a speaker unless you are drivng the speakers close to their rated output. Notice I said a little. It's pretty obvious when an amplifier is clipping. The bass gets muddy and the highs hiss. If it sounds like your listening to your speakers through a fan, then you have way crossed the line. Volume knob references are useless. Every amp and component has a different gain level, and so does every recording. At 40 watts per channel, I doubt that you're pushing any speaker unless they're just tiny close to their rated output. Simply if you hear a little distortion, turn it down until you don't.