Single ended amplifier power output and speaker choice … speaker manufacturers recommend more than 10W per channel?

You may find that speaker manufacturers specify a recommended amplifier power output range, for example 30-100W.

… and if it was a simple case of power output then no one would buy single ended valve amplifiers.

Most loudspeaker manufacturers give recommendations for the power of an amplifier, this is because if you use a poor quality low power amplifier and drive it hard, it can actually damage speakers as much as if you use an over powered amplifier.

To go into a bit more depth…

If an amplifier is pushed beyond its design maximums, the sin wave that it produces is “clipped” at the top and bottom … sort of squaring it off at the top and bottom. This then means that the amplifier is outputting its maximum power for a longer period i.e. for the whole length of the flat clipped top and bottoms of the signal rather than just at peak times. This can then damage a speaker.



Transistor amps are more prone to clipping than valve amplifiers, transistor amps have hard performance limits and set transistor outputs. Tube circuits usually have huge headroom (overload) margins due to the high voltages they run from, so hard clipping is in reality very rare in valve amps. So the minimum power output of amplifier specified by speaker manufactures is aimed more at cheap low powered transistor amplifiers.