Below is a quote from Bobby at Merlin from another current thread that sheds some light on his thoughts on amps:
i have used the joule and atma otls at shows for 10 or 12 years now. swampwalker makes a number of points i would agree with comparing the two. the merlins have a benign impedance characteristic which makes them very friendly to any type of amp, really. my favorite are otls and certain lower powered transformer coupled class "a" amps. there is also a more powerful 100 watt stereo amp made locally that i think the world of too (cat). the speakers were definitely designed around more delicate tube amps and that is why i like to use otls at shows. their uncomplicated sound pulls on your heart strings.
i personally own the joules vzn 100 mk ivs, as many of you know.