I have no directly relevant experience. But if the impedance curve of your Avior is similar to that of the Avior II, as shown in the measurements section of Stereophile’s review, I would have my doubts that the Ypsilon Phaethon would be a suitable match.
The reason I say that is that the Phaethon has a specified output impedance of 0.5 ohms, which is not much lower than that of many tube amps. And as can be seen in Stereophile’s measurements of the Avior II the speaker’s impedance is in the vicinity of only 3 ohms at most bass, mid-bass, and upper treble frequencies, and is as low as 2.6 ohms at some frequencies. 3/0.5 corresponds to a damping factor of 6! That is vastly lower than the damping factors that would be provided by almost all other amplifiers having solid state output stages, which are the kind of amps I suspect the speaker was intended to be driven with.
Good luck. Regards,
-- Al
The reason I say that is that the Phaethon has a specified output impedance of 0.5 ohms, which is not much lower than that of many tube amps. And as can be seen in Stereophile’s measurements of the Avior II the speaker’s impedance is in the vicinity of only 3 ohms at most bass, mid-bass, and upper treble frequencies, and is as low as 2.6 ohms at some frequencies. 3/0.5 corresponds to a damping factor of 6! That is vastly lower than the damping factors that would be provided by almost all other amplifiers having solid state output stages, which are the kind of amps I suspect the speaker was intended to be driven with.
Good luck. Regards,
-- Al