My system acts weird

My system is Audio Aero Capitole, Yba Passion integrated and Harbeth sHl5 speakers, kubala fascination interconnects and kubala expression speaker cables.
I have noticed that most of the time it sounds just ok.(not like it should) sometimes it sounds just plain horrible and sometimes it sounds just right. The sound can improve dramatically for a period of a few minutes and then collapse again. The best performance was during the long weekend - the music was just flowing, lovely and involving. I assume that it could be the power(I live in an old condo building). To rule out the cdp and amp problem I used borrowed CDP and AMP for a while and all the time problem still existed.
So I bought a line conditioner "Sound Application". Even though it does make a difference it did not resolve the problem.
The symptoms of a "bad sound day" are:
base is all over the place-boomy and overwhelming
Soundstage is flat and not well defined.
Entire presentation is just not enjoyable.
I consider buying a re-generator and so far it's ether PS audio Premier or APS PurePower.
If any of you had a similar problem please do share your solution.