How to make sound less detailed with warmth?

I wonder how many of the responders recommending cable changes have owned the small Thiels. My first "hi-end" speakers were a pair of Thiel 1.5s. I was immediately struck by and in love with their detail and clarity. After a few months I couldn't finish one cd, thought my ears would bleed. It's a pity as the company is an excellent company to deal with. The speaker that replaced them at that time were Vandersteen 1Cs, no fatigue and an absolute bargain at the used price.
My usual recommendation was a speaker with a fabric tweeter until I bought a pair of Revel M20s. Detail with no pain so far. There are too many good speakers out there so you should experiment.

I still believe that the dieing amp is a must.
I mean.....its days are counting. It seems like opportunity to try different amps and see what's out there. Fatigue could also be associated with non presence of any acoustic treatment. Front wall(behind the spk.) and first reflections (sides and ceiling) a must for any audio system.

I am not doubting that Thiels colored heights and overall characteristics are in fault because my inexperience with these speakers in general.

However some things can be improved with one way or the other. I would move in small steps if I was Patch 1980.
It is part of growing up. Let it happened gradually...

amp and thiel speakers are contributing to your problem. consider tubes and a different speaker. i am partial to panels, but then, you need to select a tube amp wisely.

have you considered changing the tubes in your preamp ?

Preamp: Sonic Frontier SFL-1

Patch1980, what tube are you using in the SFL-1? Try a Mullard tube.

Be sure if you are using CD as source to use only very well recorded ones as your reference for violin etc. That way you can more easily determine whether the edginess is in your equipment or the recording. See if you can borrow any other speaker that doesn't have the ear bleed reputation and see if you like the sound with your equippment. That will tell you if a speaker change would help you as much as suggested in the previous posts about Theil.