As a Thiel 2.2 owner, I love your speakers and hope they continue to live a long and happy life. I've had my Thiels since 1992 even though my amps/preamp/DAC and streaming gear are only a few years old.
Like you, I have an EE 8Switch with the stock power supply. Have you tried your switch with an LPS? I know that the power supply can have a major impact on SQ, but I just haven't had the energy or cash to explore that area in a serious way.