Thiel owners please chime in.

You might want to take your thoughts to the very extensive Thiel owners thread.

BTW, do you mean you switched to the 8 ohm out on your amp and you prefer the sound with the Thiels?  That seems very surprising to me. The Thiels impedence tends to travel well below 8 ohms, and I'd think a lower ohm tap would work better.   What difference did you hear in the sound, specifically?

I have the Thiel 2.7s too, btw.  Driven by Conrad Johnson Premier 12 tube amps.

Hi Prof....yes I switched from 4 to 8 ohm taps. Have not owned the 2.7 too long (approx 6-7 weeks) so trying to get more familiar with them but yes they are tougher to drive.  The 4 ohm made sense but I like to experiment so tried the 8 ohm tap.  The 8 ohm sounds more relaxed, focused and overall smoother.  I can't speak for long term listening yet but I was surprised I could hear quite a bit of difference.  Not sure of the longer term results but I was curious what other owners have experienced.  

Nice amps you have by the way.  I'm sure they are very sweet with the Thiels. I'm surprised by the power of my VK55. I've always loved the sound of it. Very 3D like and has good drive and focus for a 55 watt tube amp. The bass is quite good also.  Very robust.  

Interesting sam, I have tried my 2 ohm tap versus 4 ohm and prefer the 4 ohm on my Thiel CS6 and 3.6.  I have never tried the 8 ohm tap but will give it shot and let you know.

Your mileage may vary but doesn't hurt to try. Yes please report back. I'll chime in more after extended listening.  

Don't know about 2.7's, but both my 2 2's sound better on the 8 ohm than the 4 ohm.  Why, don't know given the impedance curve, although it does rise in the midrange/treble a bit.

After listening for a few days I have found the same thing, on my Mcintosh 501’s the 8 ohm tap sounds better, smoother, than my 4 ohm tap with my CS6.

I never would have guessed with the impedance staying below 4 ohms throughout the frequency range, I am assuming the CS6’s negative phase angle helps the low impendace load.  It is above my head, I just know what I hear.

From what Roger Majeski of Music Reference, and others have advised me, choosing the technically correct tap only maximizes the efficiency of signal transfer from amp to speaker. So the speakers can get louder when the "correct"tap is chosen. But, for nest sound, the way to do it is ONLY by listening, and deciding for yourself. --Warren