Thiel CS2 2 loudspeaker Measurements | Stereophile.com
Ayre Acoustics AX-5 integrated amplifier Measurements | Stereophile.com
Unlike some other Thiel models the CS 2.2's only have a somewhat small and fairly brief dip below 4 Ohms While the Ayre is not actually spec'd to deal with the Thiel CS 2.2's, and FWIW wouldn't be my choice to power them; depending of course on your room and desired volume levels I think you'll find the AX- 20 adequate.