@cagma7 standard home wiring is 14 gauge. Check to make sure. In any event I would suggest running two dedicated lines, 12awg each (10awg is obviously better but harder to work with) - one for the amp alone, another for source, preamp, phono, etc.
Moving the LED dimmers to another circuit is also an option and is going to be better than your current setup. Also, replacing the old dimmers with smart dimmers and leaving it all as is…not sure it will be an improvement. The new smart switches are wifi and may introduce noise. I know this contradicts @erik_squires recommendation but just thinking out loud here…that cure can potentially be worse than the disease but @erik_squires is a knowledgeable dude, so I will defer that to him to elaborate how that can be an improvement.