difference between power rating of tube and chip amps

[winner]

is there any diff between their power ratings?
i was told that a tube amp gives more sound than a chip one with the same power rating is it true since equations for power thru speakers r the same thruought the world

[pacificblue]

There is no difference in power ratings. Some tube amplifiers appear louder with the same input signal and gain due to their higher amount of 2nd order harmonics, but that means they are also providing more power to the speakers than a transistor amplifier or chipamp in that situation.

A second reason is that the slope of a typical tube is not as linear as the comparable Hfe of a transistor. That leads to a progressive characteristic: the higher the input signal, the higher the gain, which makes a tube amplifier more dynamic. Not only compared to a transistor amplifier, but also compared to the original signal. (That sounds worse than it is. Loudspeakers do just the opposite, and with a little luck the two effects cancel each other out.)

Then there is the point that typical tube distortion is less bothersome than typical transistor distortion, so a tube amplifier may be driven above the clipping point, i. e. above its nominal output power, and still sound pleasant, thus providing the same sound pressure level as a transistor amplifier with higher nominal output power.

Chipamps in particular often come with protection circuits that add their own distortions, when they reach their thresholds. Therefore overdriving a chipamp usually sounds even worse than overdriving a normal transistor amplifier, which leads you to avoid those situations and listen at lower output levels than with a comparable tube amplifier.