Is dirty power the culprit?

One of the most frustrating experiences I have with home audio is when one day the system sounds so wonderful you are convinced you do not need to change a thing in your system and are set for life. Then the following day or a couple of days later the system sounds like a collection of items purchased at toys are us.

All attempts at adjusting VTA or VTF or whatever you can think of is to no avail. I'm left with the only solution, shut the system down and wait for a better day.

It probably does not help that I live in a condominium near downtown Boston. I am certain there must be other audiophiles living in similar circumstances. How do you deal with this problem? Is it always a problem with electricity? I would appreciate your input.
I don't know if it's ALWAYS a power thing but my guess based on your situation is that it's very likely. There are some very good power conditioners out there. The only 2 I'd put in my system would be the BPT and the Running Springs.

If you have any equipment that's capable of running on battery power, you might want to investigate that also. My power is actually pretty good and switching over to battery is still a significant improvement.

Bryan Pape
GIK Acoustics
Remember that the human component (you) of your system is the biggest variable you have. Both your physical and mental condition affect what you perceive and those factors are constantly changing.

That is not to say your power supply couldn't be an issue, but if it is, you should be able to measure noise on the line with the appropriate equipment. A related factor could also be EMI/RFI noise that your system is picking up through the air. I've got a shortwave radio fellow who lives half a block from me and I can always tell when he's busy with his hobby, particularly if I'm playing LPs.

However, over the years, I've found I'm more often the weak link in the system than any component.
Post removed 
Are you playing the same source material when comparing?

Seems like an obvious thing but, if not, then this is a likely culprit. Not all recordings are created equal.

Mood/disposition towards listening is another likely factor.

Power? Maybe. That might be hard to prove though.

DOn't some power conditioning devices provide displays that indicate a measure of power "cleanliness" both in and out? If so, then maybe this could provide some real evidence that power is the culprit.

Also, any electronic device can have intermittent problems that prevent them from operating to spec at all times. Intermittent problems are the hardest to detect and reolve sometimes. You have to be able to swap pieces in and out one by one over a period of time and listen and compare to isolate a problem.

Simplicity can be your friend in resolving these kinds of issues. The more components in the signal chain, the more places there are where something can go wrong. Electronic gadgets are not perfect and do not always perform up to spec forever after all.
I have experienced the same problem and yes it is power related. Do a little research on EMI/RFI rejection and implementing a "Star Ground" system circuit. I no longer have the seesaw effect.
I would guess both power and the human factors cited above are likely culprits.

It could also be you just don't like your present system. I've had similar feelings about systems over the years, I'm finally at the point where I like my system all the time. While I may not enjoy it to the same level at each listening session, I never end my sessions feeling something is fundamentally wrong with the system, now chalk it up solely to mood/disposition variables.
well, for what it's worth, i live in boston as well and have experienced similar differences with my systems that i attribute to the power.

oddly, the evenings in boston seem to be the worst times for power. often things sound pretty good to me in the morning and early afternoon, but get noticeably worse in the evenings -- until 1am or so.

and it does seem that some days are worse/better than others.

oh well. i just deal with it by listening to better-recorded material or by just watching tv. flight of the conchords sounds funny with bad power or good...
one day the system sounds so wonderful you are convinced you do not need to change a thing in your system and are set for life. Then the following day or a couple of days later the system sounds like a collection of items purchased at toys are us.
Montepilot (Threads | Answers)

Montepeliot, what you describe are *extreme* swings in your evaluation of your system's performance, not marginal ones. Don't allow anyone to suggest to you this is some psycho- acoustic phenomenon, tied to your mood or emotions, or state of mind at the time. These swings in performance are tied to the AC. Other than dedicated lines, which you cannot do where you live, I really don't know of a conditioner or regenerator to recommend. My attempts with the PS Premier were a failure (it did more harm to the sonics than good in my setup) I did try the APS Purepower regenerator and I'd like to try it again. For me it beat the Premier. I'd still have it if not for a glitch with the backup batterty. If only we could isolate our equipment from the power grid altogether and have pure clean power! Then we could hear what the gear is really capable of. That would be ideal!
These swings in performance are tied to the AC.
I always admire the way that vague symptoms in a nine line post (sounds "wonderful" versus "collection of items purchased at toys are us") can be diagnosed by others with such unquestioning certitude even though they haven't seen, much less heard, the system themselves.

It would like phoning a doctor who has never seen you, complaining of generic symptoms, and getting a precise diagnosis.

Power line issues can cause problems but it is hardly the only cause. Several avenues of investigation have been suggested to the OP. I hope he finds one - or a combination of them - helps with his problem.
While I am a firm believer that the listener is a major variable, and that often differences will be perceived when nothing whatsoever has changed (including the recording), I think that if the differences here are as great as you seem to be describing, something else is going on.

I'd suggest first that you buy or borrow a multimeter, and measure your line voltage on the good days and on the bad days. Also, take an AM portable radio, tune it to an unused frequency near the bottom of the band (e.g., 540kHz), set the volume level to a repeatable point, and compare how much rfi it picks up when placed near your power cords, on the good days and the bad days.

That will address (at least roughly) two of the four ways I can think of by which power might be affecting your system (voltage and noise). The other ways would be harmonic or other distortion, and dc offset, but you would need more specialized equipment to address those factors.

Beyond that, my bet would be (as Mapman suggested) that you have an intermittent problem in one of your components. Perhaps a capacitor that is leaky and on the verge of breaking down. Perhaps you can borrow some other component(s) to swap in on the bad days.

-- Al
So if the problem is indeed dirty/variable quality power, aren't there meters or other gadgets out there that can measure and confirm this rather than guess or assume and possibly avoid a (potentially expensive) wild goose chase?
voltage variation, temperature in the room, tubes, oxidation--there are many variables.

i would consider some kind of power conditioning as has already been suggested. perhaps, you could borrow some device, before commiting to a purchase.
Maybe leave your system on for several days and see if you still experience the variation- especially if you have tubes in your system.

I hate to use the "C" word, but capacitors are strange little critters. A buddy of mine back in the 80's told me that they mechanically adjust themselves and can make a system sound dull until they have had time to form. Fact or myth, I know that if the amp/preamp has been turned off for several weeks the system will sound dull for a day or so.

But even back then, my buddy's tube amps would some nights sound dull and they attributed it to the caps.
Leaving the amp on is a good idea for a test to see if that makes things sound more consistent. Problem is it is not practical with tubes on a regular basis because you will shorten tube life. Works good with SS amps though. I do it all the time.