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.
avialuf
Avialuf, how many measurements did you take and for how long ? Did you check the line voltage when the sound was bad ? A quick check here and there may not provide the whole picture. The best way of checking longterm voltage stability, is to use a datalogging meter (digital multimeter with PC interface) and software. It can be left connected to the AC for about 24 hours and logs power quality for that period. Unfortunately those can be quite expensive. I have one that I bought from Radio Shack many years ago, when they sold pretty decent meters.
Thank you all for the replies.
Lak-yes it sounds better in the early morning and during weekends. There are tv,dvd,modem,computer and router on the same fuse (unfortunately I can't remove them, at least not now) but they are not plugged into the conditioner or the same outlet. Also the same appliances connected on "good" days too so I would assume they are out of the accusation.
Gbart -good comment but those meters are very expensive.
I measured the voltage during good and bad days for a few minutes and it's always about the same.
Onhwy61 - yes it's on 24/7.
This ordeal made me listen my system less and less now - it's really upsetting after all the money spent and all the effort to enjoy it only on those "good" days. What I think really affect the system is the "air-conditioning" season - there are a lot of old clunkers in the building and I can hear them working 24/7.
I think the problem might be due to the power (AC) being supplied to your "old condo building" and all the other items from neighbors that are running and polluting the AC. I've never had this happen to me personally because I live in a newer development in my home. I have read of similar situations over the years that sounds like what you are describing. I'm uncertain as to what the solution is. A different way to clean the AC would be with a used isolation transformer (see my power filtration picture in my system). I have a friend that solved his AC problem in his apartment by plugging in an isolation transformer to the AC wall outlet (he wired it for that) and he installed a high quality AC outlet on the other end of the isolation transformer that he plugged his system into. I don't know if that would help any better than what you are currently using.
Have you lived there long enough to know if the problem is seasonal? If yes, and the problem is summer, than utility use by neighbors may be the culprit.

My voltage goes from a low of about 115 during the heat of the day to 118 / 119 very late.