bought a Belles Aria recently and compared it to a Rogue Sphynx, I prefer the Sphinx, but it does matter which tubes you use in the Sphinx, my favorites being NOS Mullards. I'm finding it hard to explain all of the differences, the Aria has a lighter, brighter sound in my system to my ears, the Sphinx has a fuller, darker sound. The Aria shines on low volume delicate music, the Sphinx shines on vocals and more dynamic music. The Aria edges out the Sphinx in the reproduction of piano, the Sphinx is a tad harder sounding. Simply put I enjoy listening to the Sphinx more, I listen mostly to jazz. I'm keeping the Sphinx and selling the Aria.