Dedicated line w/ upgraded parts or power cond?

Whart - have you tried a floating shield approach on your power and interconnect cables?

All good advice from the previous posts, and in my opinion it can be an individual system dependency and/or local AC power company issues.
I remember reading posts from past topics where some said dedicated power circuits made an improvement and others said they did not notice a difference.
Years ago I first used a power conditioner which was an improvement.
Next, I installed several dedicated 20 amp circuits with high end outlets, which was another big improvement.
I actually removed the power conditioner and injoyed the dedicated circuits and AC outlets, however I finally installed two Xentek Extreme Isolation Transformers which make up my major AC power filration system.
I use two 5 KVA Isolation Transformers into sub-panel that feeds all the dedicated AC power into my systems.
A picture of my power filtration system is shown in my virtual systems.

Willie- I haven't really fooled around with the interconnect pin configuration or wiring- I run XLR from phono stage to line stage, and xlr from line stage into Lamm ML2 amps, but the latter is not a true balanced input. I have floated grounds on power cords in the past to sort 60hz hum issues but try to ameliorate without any ground-lifting. I think some problems may arise from how individual components are internally grounded, but i'm not expert enough to determine that. The external star grounding approach has worked in some set-ups using the horns, although right now, the system is extremely quiet without it. I will occasionally hear noise over the system that comes from a power anomaly on the line, or a microphonic tube, but I've been pretty lucky. I did find that having separate dedicated lines created more potential grounding problems, but right now, fingers-crossed, the system seems to be in fine fettle.
I'll be interested to see how the Equi=Tech performs once I'm set up in a new room. That may be a while, though.

Go with a couple of dedicated lines and use good receptacles,the better they are the better the sound.

Then plug your power amp(s)into one line and the rest into the other.
I also like a third line for just the digital stuff.

This will improve your sound.

Next improve your power cords to all gear.
Keep them from the same company or DIY but use connectors and wire from the same manufacturer, and don't scrimp.

Then try a power conditioner,for the front end gear,one that isolates digital from analog as a starting point.

Then try some upgraded fuses, which should be the icing on the cake,but, after all the power upgrades are done before it. You should now be able to hear what they bring to the party.

When you've gotten the power taken care of you can then audition wires,because now you'll hear the differences between them when all the noise has been cleaned up.

In fact you'll be able to hear your system for the first time, and you may not feel the need to replace anything again.

Then go for a power conditioner for your front end gear

Whart - "floating shield" is not quite the same as "floating ground"

For instance, with floating shield, if you have a power cord with Positive, Neutral and Ground conductors, then all three should be connected at the IEC and mains connector - however, the shield ONLY is connected at the mains connector.

Theory is that any RFI is conducted away from the component connected to it

It works very well with a star grounding scheme

It could be accomplished with XLR using todays multi-shielded balanced connectors, but XLR cables generally are not constructed with a floating shield so I wouldn't consider changing anything with your XLR cables.

The occasional noise interference you attribute to power line anomolies may well be eliminated by the Equi=Tech solution

The explanation on their web site states that the noise on the incoming power line phases are 180 degrees opposed and therefore cancels out when put through their system.

If the noise on the phases are equal in amplitude - they would be correct - but we live in an imperfect world.

However, the differences would probably be so small as to render them innefective

One point of interest, they warn against floating shields - from their web site...

all audio cable shields be grounded at both ends.

Not quite sure as to why they state this - maybe they are assuming there is no seperate ground conductor and the shield is used as ground, by default - which may be true in some cables

Keep us posted on how it works out