Dedicated 20 amp lines/should i use a sub panel

Welcome to the perennial problem of dirty power. Turn off all dimmers and use only incandescent bulbs. Heating boilers, appliance motors, phone charging adapters etc all add noise. Note that your hearing is more sensitive late at night so music sounds better then.

@indranilsen, AC power coming into our homes is always in a state of change. Fewer people up after midnight using power so the incoming AC could be less polluted as noromance stated.

A balanced power transformer could possibly allow you to hear more details in the music and maybe even a better soundstage however it might not necessarily get rid of the slight hiss you hear from your tweeter.
Personally, I wouldn't be concerned of the hiss.

@noromance/@lak,
Thanks for your feedback.
It seems like the hiss coming out of the speaker tweeter is a non-issue and in-reality that's not bothering me at the moment. So I would ignore it....
However turing off all lights/heaters/furnace etc is not going to be a realistic solution... Would a balance power transformer with its so much advertised common-mode-rejection functionality be able to  address the inconsistent A/V performance issue during day/evening? These items are expensive and relatively difficult to install, specially the units that connect to a 240V power supply. That's why I wanted to get an idea from this group before getting started on this project. For those who have this or similar power issue what do you do to avoid/eliminate it?
Thanks.

Hello Indranilsen,

The first thing I would do before deciding how to proceed would be obtain a multimeter, if you don't already have one, and measure the AC line voltage at various times of the day and night over the course of several days.

If you find that there is a correlation between the variations in sound quality and changes in line voltage, a power regenerator, such as one of those made by PS Audio, might be a solution. A regenerator is likely to also be helpful if noise or distortion on the AC line is contributing to the problem. On the other hand, though, some people have reported here over the years that in their systems some regenerators have resulted in compromised dynamics.

Also, in a thread several months ago you indicated that you were considering upgrading your Parasound Halo A-21 amplifier. If you haven't yet done that, I would suggest that you re-assess the situation after purchasing the new amplifier before deciding how to proceed. It's possible that a different (and presumably better) amplifier may be less sensitive to the power line anomalies at your location than the present amplifier.

Good luck. Regards,
-- Al
 

A balanced power transformer is most definitely an improvement and well worth it - I use them - one for my power amps and one for the front end.

The slight hiss you hear is generated by current running through resistors,  transistors and other components in your amplifiers - all electronic components have this to some degree.  Some resistors have lower noise than others, same goes for Transistors etc.  Its not something to worry about.

Good Listening

Peter