Amp vs preamp question

Matching amp to speakers and speakers to room is most important to get right first. Cost to accomplish this is secondary. Larger rooms will generally cost more to get right.

Once you have this planned out, a pre-amp to match can be determined. You need to consider what kind and how many input sources the pre-amp must handle.

Tell us something about the speakers and room you are working with first and then it should be possible to offer some useful suggestions.

Also, knowing you overall budget for both amp and pre would help.

Each piece contributes to the sound.

The engineering principle of bottle necking comes into play when "tuning" your system. Basically, this means you make sure the part furthest downstream is not "bottle necking" or limiting performance. Once this part is tuned, then move to the next piece upstream.

Unfortunately, if you do not make sure the amp can drive the speaks properly in you listening environment first, you will have a bottleneck downstream and not be able to get the most out of your expensive upstream electronics no matter how much money you throw into them.

" the choice of preamp will give a profound, perhaps more significant improvement."

I agree the impact of pre-amp will be profound.

How exactly does one best go about chosing which pre-amp will be best at this point though?

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.

Douglas Schroeder has a good point.

You want to be sure what you buy synergizes well. If you are not sure what will, an integrated would be a safe bet. Just make sure the amp can drive the speakers adequately.

Another option is trial and error. Buy used and don't overpay if that is the way you want to go, then if something doesn't work out you can sell and buy something else without taking a loss (who needs more of those these days)?

Usually, its the bass at lower to moderate volumes that suffers driving speakers with difficult loads with amps that are not up to the task.

IF you're willing to live with that for some other aspect of a particular amps sound, then I guess you will be fine, but you may not be getting everything that your speakers are capable of delivering at lower to moderate volume.

In my case, I replaced a 360w/ch Carver amp that did not come close to doubling output with impedance with a ~100w.ch Musical Fidelity that does.

The Carver went louder and sounded fine at higher volumes, but the bass and dynamics were noticeably missing at lower volumes. The Musical Fidelity does not go as loud, and the sound is dynamic and balanced now at the volumes I more typically listen at.

The numbers are just guidelines to help narrow the search and get you there quicker. After that, its largely subjective...a matter of taste.

I'd consider some of the more powerful Class D amps with the Thiels to get them fully fleshed out at reasonable cost from what I'm reading.