Genesis ribbons are fairly stable 4 ohm loads with a bit of trouble in the 85 to 200 Hz area that is taken care of by the crossover. OTL's might not be the best choice because they are designed for 8 to 16 ohms, usually. Some of the bigger Atma-spheres have no problem with 4 ohms. One thing to consider on the OTL's is the cost of retubing every few years. There are tube amps, like Manley that are designed for low ohm loads.
I have heard people swear by both SS and tube amps for the Gennies but they all say they like lots of power. Not sure if speed is an issue but tubes usually have a slew rate much slower than SS. Edge and Monarchy make some of the fastest nowadays.
http://www.atma-sphere.com/papers/myth.html
I have heard people swear by both SS and tube amps for the Gennies but they all say they like lots of power. Not sure if speed is an issue but tubes usually have a slew rate much slower than SS. Edge and Monarchy make some of the fastest nowadays.
http://www.atma-sphere.com/papers/myth.html