Amp vs preamp question

square rooms gives grey sound
rectangular rooms give color sound, to my ears.
= grey vs. color = diferent harmonics.

no matter if the speaker and amp are the best, the room can make them sound ugly.

power also , needs balance, big room needs power.

but, electronically speaking,
speakers, amp & cables are more important than pre-amp.
the best pre can only perform as good as your speakers or amp.
the weak link its your best.

I see no inconsistency in most of the arguments above. I'm in the "garbage in, garbage out" camp. So I view the pre-amp as being more important than the amp. This presumes, however, all other things being equal. The amp has to mate well with the speakers and the system has to be tuned for the room, or vice versa. So if you have an amp that is suited for the speakers, and if your room acoustics are good, then all things are equal and a preamp upgrade should do more for you than an amp upgrade.

Thank you very much for your help
I am thinking about BAT vk 51se preamp and Rogue Audio Zeus Amp

Can you give me some more advice?

The Thiel 3.7's drop to 2.8 Ohms, very few tube amps are at their most comfortable operating into such a load.

I'm not a Thiel guru, but it sounds like tube amps are not a good match to the Thiels due to difficult load.

You might be better off going SS on the amp and tubes on the pre-amp, if that's the sound you like. The SS amp should double power to 4 and 2 ohms as discussed above due to the load.

I'm sure others may have some specific suggestions regarding what works good with Thiels. If it were me, I'd consider some of the better Musical Fidelity amps of perhaps something Class D, like Bel Canto or Rowland maybe.