Thiel CS1.2 vs. Ohm Walsh 2

Wait, isn't your Denon 80 watts per channel? If so, I would think you have enough power for the Thiel's, at least for now- and, if you don't try playing too loudly.
If you need a decent low cost amp, you could try to find an old Adcom GFA-555, but they are a bit long in the tooth.
I would suggest finding a used McCormack DNA-1. or .5. The best thing is that you can send it to SMcAudio for upgrading down the road.
A Belles Aria integrated would be another suggestion.
Unfortunately, they cost a bit more than $300, but when you move up to a high fidelity speaker, you have to get higher fidelity equipment to power it.
FWIW, I think the Denon will be fine, for now. I've driven 4 ohm speakers without issue using a receiver pf lesser caliber years ago. It sounded pretty good, too.
Bob

To use the Denon as a preamp you need a stereo variable line out.  If the line out is fixed .... it won't do. If it has a stereo pre out ... that would be best.

If the Denon is not 4 ohm stable, then the risk would be to the speakers.
When speakers ask for more power than the amp can safely deliver, then the amp clips, and speaker components overheat, literally frying the speaker and potentially damaging speaker components.

If you can stretch your budget to $399 ... then my suggestion would be to look at the Emotiva TA-100 in their BASX line.  You could buy that directly brand new from Emotiva ... and that should match up well with the Thiel CS 1.2 speakers.   And that is well suited to being used as a starter pre amp down the road.

if the Denon in question is actually the AVR X1100w then here is the specs from web manual-

o Audio section
0 Power amplifier Rated output:

Front:
80 W + 80 W (8 Ω/ohms, 20 Hz – 20 kHz with 0.08 % T.H.D.)
120 W + 120 W (6 Ω/ohms, 1 kHz with 0.7 % T.H.D.)

Center:
80 W (8 Ω/ohms, 20 Hz – 20 kHz with 0.08 % T.H.D.)
120 W (6 Ω/ohms, 1 kHz with 0.7 % T.H.D.)

Surround:
80 W + 80 W (8 Ω/ohms, 20 Hz – 20 kHz with 0.08 % T.H.D.)
120 W + 120 W (6 Ω/ohms, 1 kHz with 0.7 % T.H.D.)

Surround back:
80 W + 80 W (8 Ω/ohms, 20 Hz – 20 kHz with 0.08 % T.H.D.)
120 W + 120 W (6 Ω/ohms, 1 kHz with 0.7 % T.H.D.)

Output connectors: 4 – 16 Ω/ohms


Thiel CS1.2 

https://www.stereophile.com/content/thiel-cs12-loudspeaker-measurements

Link from Stereophile review measurements show what looks to be a fairly balanced impedance load.  If the Denon is not asked to play in excess it would appear that it would and could work at reasonable SPL.  Problems arise quickly when clipping of the amp is introduced, ie- blown tweeters usually happen first.  Again, given a safe dynamic range to work within the Denon looks like it will work, just not up to the optimal level the Thiels would prefer or shine in.

@bryhifi . 
+1, thanks for retrieving all the information.
Bob

For the Thiel CS 1.2’s; I’d suggest an amp capable of at least 80 clean Watts into 4 Ohms.