Sound Lab A-1's go down to around or slightly below 2 ohms in the very high treble, to the best of my knowlege.
I used to use Strathearn ribbon drivers in homebrew speakers, and they were a .55 ohm load.
Amplifiers that can drive such a load include the Electron Kinetics Eagle 2 (which is what I used on the Strathearns) as well as the InnerSound ESL amp (stable into a .33 ohm load). I think the Claytons are also stable into .5 ohm loads (Disclaimer - I peddle these two lines, which is why I'm familiar with 'em). I'm sure there are many others.
It's too bad the amp-killer early Apogees and early CLS's aren't still being made, as these days there are relatively affordable amps that can drive 'em.
Duke
I used to use Strathearn ribbon drivers in homebrew speakers, and they were a .55 ohm load.
Amplifiers that can drive such a load include the Electron Kinetics Eagle 2 (which is what I used on the Strathearns) as well as the InnerSound ESL amp (stable into a .33 ohm load). I think the Claytons are also stable into .5 ohm loads (Disclaimer - I peddle these two lines, which is why I'm familiar with 'em). I'm sure there are many others.
It's too bad the amp-killer early Apogees and early CLS's aren't still being made, as these days there are relatively affordable amps that can drive 'em.
Duke