Had this same experience, that is until I put in a dedicated 20 amp line and purchased a PS Audio P20. Power conditioning is a must and it has to be with a product that has super low impedance. The grid is super noisy. I am not necessarily pushing PS Audio but I am a fan of power regeneration and in my experience it will get you the best sound at all times of day. Now it is always midnight with regard to my sound. I also keep my kit on standby always. Also, during the day, you may want to try a eye sleep mask. I know that may sound silly but if have found it puts you in a different space when you cannot see anything and can just focus on the sound.
DISCUSSION: "It only comes out at night". Does anyone else have this experience!?
In my listening experience, whatever system you have, whatever components, whatever the material, medium, one thing always seems to remain constant. It ALWAYS sounds better in the deep and still of the night!!!
Is it because night time is generally quieter? Is it because the world of electronics is then shielded from the SUN? Is it because there is less demand on the electrical service?
Whatever it is, there is one thing I know for sure, music sounds better late into the night!