@robd1
Is this statement from @atmasphere above true?
"At the other end of the range, the speaker is pretty low impedance (1.5 to 3 ohms depending on the position of the Brilliance control) which will cause most solid state amps to be too bright and nothing for it but to turn down the Brilliance control and deal."
That is, if it’s a low impedance speaker, an underpowered (or maybe not enough current) solid state amp will sound brighter?
Yes it is true, but the answer to your concluding question is ’no’. The more the powerhouse amp, the worse this problem becomes:
The comment is regarding a Sound Lab ESL, which is about 30 ohms in the bass and has the impedances stated above at about 20KHz. Like many ESLs, the impedance curve goes from high impedance in the low frequencies to low impedance in the highs, covering a range of about 10:1. If you put a solid state amp on that, it will be bass shy and way too bright, due to the amp likely acting as a voltage source (IOW, can double power as impedance is cut in half). For this reason, you can see that ESLs are generally incompatible with solid state without special measures being taken.
Its important to understand that the impedance curve of an ESL is not also a map of its efficiency (they are quite unlike a box speaker in this regard). They tend to have the same efficiency from lows to highs. Their impedance curve is based on a capacitor which is the basis of their operating principle.