[DSK]

Something that caught my eye recently as I wandered around the virtual world ....

A VTL ST-150 tube power amp, rated at 150w per channel, with 4 & 8 ohm taps, had an accompanying comment that it was "recommended for use with speakers with sensitivity of 92dB or higher".

I wondered why this would be? I can understand not wanting to run a tube amp on a speaker with an erratic impedance curve but this did not seem to be the reason.

[Niteshade]

It is my opinion that speakers that are at least 90-92db efficient are better than inefficient speakers. Good speakers can be purchased that are efficient. Inefficiency is a synonym attenuation. Why would anybody want to attenuate an amplifier's output? The volume has to be turned up further with the end result being heat (generated by the amplifier) and not sound. Efficient speakers will be compatible with considerably more equipment that inefficient ones. It's not good to limit your system.

I believe what they were trying to say is that the amp will perform better with efficient speakers, even though it's 150 w/channel. Low efficiency speakers soak up a tremendous amount of power and, unfortunately it isn't anything you hear. Amplifiers sound better when they're not being ran near their maximum rated output.

Here's a very good article on the subject:
http://everything2.com/index.pl?node_id=1523585

Something that caught my eye recently as I wandered around the virtual world ....

A VTL ST-150 tube power amp, rated at 150w per channel, with 4 & 8 ohm taps, had an accompanying comment that it was "recommended for use with speakers with sensitivity of 92dB or higher".

I wondered why this would be? I can understand not wanting to run a tube amp on a speaker with an erratic impedance curve but this did not seem to be the reason.