Amp power ratings help determine how loud and clear things can go in various size rooms, but there is more to what the right power amp brings to the table sound quality-wise.
Current delivery (peak amps) is a better indicator of how well an amp will drive more difficult load speakers like Thiel even at low volumes. Driving better at low volumes generally means better tonality, detail, articulation and most other things associated with good sound, a more natural and "effortless" delivery top to bottom. A 40 watt power amp with high current delivery will sound different and likely much better, all other things aside, than one with less, in the case of the Thiels.
Source improvements may be hard to assess if the bottleneck is the amps ability to drive the speakers to their max, even at lower volumes, due to limited current delivery, as is more typical with integrated amps than separate power amps due to the physical limitations imposed by having powr amp in close proximity to line level and even lower phono level circuits.. Once amp/speaker combo is in a good place, then one is in a better position to assess how well changes in source devices work or not, and it will be much easier to make improvements with that from there.
BTW, most speaker designs that target extended bass in a smaller box (a popular choice practically for many these days) is likely to be a difficult load for an amp to drive. Thiels are just one case. They are very good speakers. Just not ones that will perform equally well with just any amp.
Current delivery (peak amps) is a better indicator of how well an amp will drive more difficult load speakers like Thiel even at low volumes. Driving better at low volumes generally means better tonality, detail, articulation and most other things associated with good sound, a more natural and "effortless" delivery top to bottom. A 40 watt power amp with high current delivery will sound different and likely much better, all other things aside, than one with less, in the case of the Thiels.
Source improvements may be hard to assess if the bottleneck is the amps ability to drive the speakers to their max, even at lower volumes, due to limited current delivery, as is more typical with integrated amps than separate power amps due to the physical limitations imposed by having powr amp in close proximity to line level and even lower phono level circuits.. Once amp/speaker combo is in a good place, then one is in a better position to assess how well changes in source devices work or not, and it will be much easier to make improvements with that from there.
BTW, most speaker designs that target extended bass in a smaller box (a popular choice practically for many these days) is likely to be a difficult load for an amp to drive. Thiels are just one case. They are very good speakers. Just not ones that will perform equally well with just any amp.