What component is responsible for dynamics ?

The OP needs to restate the question as "what component(s)" since it is multifactorial. People have harped on the expected variables. I too believe mechanical grounding is important along with room construction and these things are often an afterthought. Also, source material plays a role, and is something we cannot control. There is no way to fix compressed Redbook....

Saki70, in my experience virtually everything can impact dynamics. I have enhanced dynamic with dacs, amps, ac filters, vibration controls, cables, and even wall outlets. So, I agree largely with Agear.

Wow , I had forgotten about this post !

How does this sound in answering my question here ?
This is an excerp from a post asking for feedback on Reference 3a speakers :

03-29-13: Martykl
I had deCapos for quite a while. I think they employ a very specific set of trade-offs to achieve a specific result.

They combine better bass extension than most stand mounted monitors with a truly neutral octave to octave tonal balance. That's unusual IME because the lack of true bottom end energy (true of this and basically all other small box speakers) requires limiting the output thru the presence and treble region to maintain the octave to octave neutrality. Most manufacturers seem to maintain more output in the upper octaves so that the speaker sounds more dynamic. The result - to my ear - is that the vast majority of stand mounted monitors tend toward a bright voicing that would benefit from the addition of a subwoofer.

The real world result of the Ref 3a approach is a monitor that sounds really neutral. It doesn't really invite the use of a subwoofer - it would sound bottom heavy if you added one. OTOH, it definitely struck me as polite sounding and limited in dynamics.

To my ear, maintaining neutral balance at the expense of dynamic "jump factor" is a wise trade. However, IMO, that is the price that was paid in this design.

This could explain the lack of dynamics in my system .

Any comments on this explaination ?

Thank you

I still say find Grand Veenas or at least Murata super tweeters. I haven't seen

Unless one is using very dynamic speakers, which as you describe, you are not, different speakers are the way to increase dynamics. Amps, preamps, phono stages, cartridges can vary brand to brand and model to model in dynamics, so you can enhance dynamics without changing speakers. But, again, for sure, speakers are the way to get major improvements.