Does an Audioquest Niagra 1200 limit amplifier dynamics?

My Niagara definitely does not smooth over the sound in my system. If anything, it lowered the noise floor to where bad recordings still sound bad but good recordings sound even better. 

All the best,
Nonoise

I used to have the Shunyata Hydra and indeed was limiting the dynamics. I tried the Niagra 3000 and noticed a difference immediately, I was able to trade the Shunyata and pay the additional cost of the Niagra.

Remove all the power conditioners, get your electrical panel and dedicated lines working instead. Those Niagara's definitely limit the potential of your system when you have clean power. 

However power conditioners served me well when I didn't have a dedicated electrical box and lines. Conditioners solve a problem that shouldn't exist to begin with.

My Bryston Bit 15 seems to do no harm...a huge Piltron transformer.

I don't know the answer to your question but I do know that the answer can vary for each individual person's system, power set up in your home, and the AC power in your area and entering your home.