I don't have CS 1.6s, but I have been using Manley Stingray push pull amplifier for over 20 years with 4 different pairs of Thiel speakers including CS 1.9 and CS 3.6 (which I guess are the closest to CS 2.6 with very nice results. In fact I tried other more powerful solid state amplifiers for either of these speakers and result was worse. In general, Thiel speakers sound nicely with tube amplifiers, with an open and real soundstage, quite clean.
