I've got the Summertime Blues. Power conditioner necessary?

A friend in an apartment building had a similar problem. I gave him a large Constant Voltage Transformer that I had purchased as surplus for $60. It solved his brownout problems cheaply.

At my own home, I had the electric company increase my home service from 100 amp to 200 amp, then had new dedicated power lines run from the service box just for my system.
Good Luck

My system has all digital sources, and I've found that the better the quality the AC power is, the DACs extract more detail with less distortion.

I used to have a very nice, modestly-priced Furman unit.  When I upgraded to a PS Audio P10 Power Plant, my DAC immediately sounded better.  I recently took advantage of an upgrade, trading in my P10 for a P15, and immediately, both of my DACs provided better bass, more detail and better soundstage.

 I use Chang LightSpeed power line filters and they work great! They have digital and analog AC connections.

Found them used for $400 to $500 and use them on my main audio system and home theater.

Also protect from lightning strikes.

For several years I lived in an area that’s electric power was supplied with large diesel generators, bad wires and noisy transformers. Running my equipment through a APC power conditioner, on it’s own circuit, helped clean most of the noise and stabilize the erratic voltage drops and surges.

While I agree that a good power conditioner can help and does add a level of protection, there are many myths and an abundance of false info. regarding your power supply.

As cleeds pointed out - you Can Not put a sub panel on a separate ground; all grounds must be connected to the common ground at the main.

You can eliminate ground noise by connecting to one end or the other of the circuit panel. No - all circuits are connected together on a common ground. The best solution, if you can - eliminate the source of noise - usually an appliance or component with a bad transformer, rectifier or ballast
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A dedicated 20A circuit with 10awg wire to supply your audio components. Really? With the exception of a very few high currant power amps - what audio components come with, or are required to have a 20A cord or, in any way, require or would benefit from a 20A circuit with a 10awg supply line? They don’t!

Have the power company provide you with a separate power supply for your stereo system? Power companies supply power to your main; the supply main, the primary panel, and sub panels are the owners responsibility and are required to meet the NEC. To get a separate service is very expensive and is only practical if you are operating a commercial business, that needs to be kept separate from your home, or have a shop operation requiring large amounts of additional power.

Not trying to be snide, just saying - some of the ideas thrown out here are impractical, improper or, in general, make 0 difference in the sound or performance of one’s audio system....Jim

The American standard ANSI tolerance of electrical supply is given at 120v +/- 5% @ 60Hz. That would be 114v - 126v. Most US power supply companies operate well within that range and 120v electrical devices, including audio components, are required to operate properly within those parameters. In the community where I am now, I seldom see the input line voltage reading on my APC power conditioner, very by more than one volt, either side of 120 and typically holds steady at 120v.
Doing a simple 120v circuit test, you should expect to see the same voltage at the last outlet of the circuit as at the breaker - if all outlets and connections are good. Even with devices, sa. TV, DVD player and a 60w lamp, in operation, doubtful you would see even a .5v drop at the end of the circuit.
US compatible electronics, including high dollar audio components, are designed and built to operate on a standard 120v, 60Hz, 15A household circuit - beyond using quality receptacles to insure long lasting good connections and keeping audio devices on circuits somewhat to themselves, there is no audio advantage to dumping $$$ into specialized panels and circuits for your audio gear....IMO...Jim