You would think the Quad amplifier suggestion has to be a good one.
Ed, I do have to say that I am unsure if you can find a more reliable amplifier than the Atma Spheres. The tubes last a long, long, long time (Ralph has an M60 with over 20 years on the original output tubes), and the bias has never drifted, in my experience. That being said, the biasing procedure takes all of about a minute if you ever need to do it (I do it on my Christmas vacation each year) - again, it's never drifted on me.
They are as "set and forget" as a CD player. Believe it or not. I have shorted the amp many times, sometimes just for fun to show people, never with any damage to either the amps or speakers. I have even forgot to install some of the driver tubes in them once, with also no damage whatsoever.
Now, when it comes to the combination of them with the Quads, I hope there is someone among us who can speak to it.