Csontos, you might want to read this:
http://www.atma-sphere.com/Resources/Paradigms_in_Amplifier_Design.php
On ESLs, OTLs are often described as 'the best'.
Tubes in general usually work better on horns and high efficiency speakers than transistors.
Some speakers are such low efficiency and/or impedance that you need an amp with a lot of power and is comfortable with low impedances. In such a case transistors will likely serve better (despite the misgivings I have about transistors).
If you read the article at that link then you know more than most about the matching issues involved.
http://www.atma-sphere.com/Resources/Paradigms_in_Amplifier_Design.php
On ESLs, OTLs are often described as 'the best'.
Tubes in general usually work better on horns and high efficiency speakers than transistors.
Some speakers are such low efficiency and/or impedance that you need an amp with a lot of power and is comfortable with low impedances. In such a case transistors will likely serve better (despite the misgivings I have about transistors).
If you read the article at that link then you know more than most about the matching issues involved.