DISCUSSION: "It only comes out at night". Does anyone else have this experience!?

There's an easy way to test and see if your system really does what it says it does. If it is truly isolated then it will disconnect from AC and run entirely off batteries. When this happens you will hear the sound improve, and because it is running off batteries and truly isolated it will sound the same regardless of the time of day or anything else. You already said this is not the case so you yourself know it is not isolated as claimed.

Another way I know is another member with the same setup experienced the same thing. 

Third way I know is from personal experience with battery isolation in my own system. It is easy to hear the improvement when going completely off AC and running off battery power. It is also almost as easy to hear the degradation when running off battery power but still connected to AC via the charger.

What happens is really no different than what happens in the power supply of every component. Theoretically, these are all "isolated" by power supply caps. Lots and lots of manufacturers claim, and lots of audiophiles believe, that enough power supply filter caps means nothing upstream from this can matter. Power supply transformers after all are transformers. If you know how a transformer works, there are two coils, primary and secondary, with no physical connection between them. This does work to effectively filter out some of the noise riding on the AC line. Some, but not all.

Reality is that as long as there is any connection at all, including even through a transformer, then AC line noise will get through. This is why you hear the sound change even though if your system worked as claimed it would be perfect isolation and sound the same 24/7. 

There is no guessing involved. This is not a case of what I "believe" to be the case. This is a case of what I know to be the case three different ways: personal experience, others experience, and a solid understanding of the subject.

Interestingly, your own experience corroborates everything I'm saying. 

all my equipment is behind a UPS that completely isolates AC output from AC input by reconstituting the AC voltage and sine wave from a bank of DC batteries.

But, I still notice it.

So where exactly does gaslighting come into it?

The guy selling it says it works. Imagine that!

Just one difference between actual experience and ad copy.

 I can’t recall what the “technology” is called, but all my equipment is behind a UPS that completely isolates AC output from AC input by reconstituting the AC voltage and sine wave from a bank of DC batteries.

But, I still notice it.

Right. Because your "technology" does not completely isolate. Your batteries are connected to the grid for charging. AC grid noise gets a free ride. A known problem. A member in Singapore has this same problem. He got it for the frequent power outages. He didn't know about it until he started noticing his system sounded better every time the power went out. The solution is a relay that physically disconnects your battery bank from the grid when listening.

Steve Deckert at DECWARE wrote a newsletter a while back and stated that speakers do not sound optimally until they have been running a minimum of 30 minutes....this allows the coils to heat up and expand.

For a long time now I have wondered why my amp and turntable, everything can be on and running, but still there is a lot of improvement the first 20-30 minutes playing music. The voice coil thing makes a lot of sense. Voice coils definitely do heat up. A lot. They can actually smoke and literally burn out. All good machinists know to get precise measurements parts must be cold. Even handling, your fingers can warm a part enough to make it expand. So heat expands the voice coil, reducing the voice coil gap, which since magnetic fields vary as the inverse square of distance wala! everything gets better. 

Brilliant! Thanks!

As with most things audio it is not any one thing but rather a bunch of them all together that makes the difference. Try coming home at 2AM firing your system up cold and see how it sounds. So one reason it sounds better late at night is it always sounds better after being run several hours. 

All components are highly susceptible to vibration. One source of vibration is cars and trucks, wind, and even trees. Wind blows, trees move, roots transmit vibration into the ground. This all tends to die down and be less at night. Best of all is a fresh blanket of snow. So, vibration.

Then there's electricity. Pretty much everything running puts a bit of back EMF onto the line. Every wire is also an antenna bringing RFI noise into the system. A lot of RFI sources tend to be off late at night.

The validity of some of these effects is easy enough to test and verify. Vibration? Pods and springs work, and the sound in the afternoon with a calm fresh blanket of snow is at least as good as late at night if the wind is blowing. Leaving everything on and playing after you got to bed, you will hear almost all of that great late night sound the next day. So this proves the warm up effect. RFI? Disconnect a lot of wires by flipping circuit breakers. It will sound in the middle of the day about as good as late at night.