To Hans Wetzel,
I have recently been gifted a pair of MartinLogan Aeons. Since I live north of Reno, Nevada, I find myself in an audio desert. Best Buy's Magnolia shop has nothing special. At the other extreme is a Pass Labs dealer. So, I'm sure by now you know what the question is: 50Wpc Arcam A19 with, as you stated, top-to-bottom refinement, or the 100Wpc Rogue Audio Sphinx, with more power and a midrange that excels? I could go on. Will you ponder the thought and advise me?
One heck of a gift, Stefano. The one noteworthy thing about the Aeons, like most electrostatic loudspeakers, is that they're pretty challenging to drive. They have a stated 4-ohm nominal impedance, but drop to a cringeworthy 1.32 ohms at 20kHz. That is downright brutal on any amp. While neither amp is perfectly suited to tackling such a load, I think at reasonable volumes either will get the job done. A doubling of power, which is what the Rogue gives you, only provides you with 3dB more volume. On the other hand, the Sphinx has a slightly more robust power supply, but is also 40 percent more expensive at $1395 (including optional remote) versus the A19's $999 asking price. So pros and cons with both.
If you have the funds, I would spring for the Sphinx -- the extra power and larger power supply are practical improvements, while its exciting midrange should complement the Aeons' lightning-quick electrostatic panels. Honestly, though, you can't go wrong either way. . . . Hans Wetzel