Tube amps and speaker matching


Recently I read somewhere that tube amps are not good at driving speakers which have a wide impedance curve, say if the impedance swings from 3-20 Ohms across the audio range. On the other hand speakers with a narrow swing like 3 to 9 Ohms who be a good match for the tube amps. Is this correct? What is really the ballpark figure to make a judgment if the speaker and tube amp combination will be a good match.

Long time ago a fellow audiophile told me that as a rule of thumb the speaker sensitivity should be in the following range for a good match:

Below 90 dB/spl Solid State only
90-100 dB/spl Solid state or tubes
Over 100 dB tubes only

As for my personal experience I have heard a 12 watter drive the Dynaudio Contour 5.4 and was very listenable, similarly I have also heard a Cary amp with just five watts drive a pair of Maggies. I personally have driven a Quad 15 watt vintage tube amp with the Maggies. All these combinations to my ears sounded pretty listenable albeit one could not drive them hard as the amps were very low powered.

Can anyone enlighten me with their opinion?

Thanks
128x128quadophile

Showing 1 response by philjolet

in general, tubes like a higher impedance (8 to 14 OHMS)

I have not heard about impedance swings being a problem but I doubt it is a major concern

we shall see as others chime in...