@viber6 ,
Respond to your technical insights? Those were not technical insights, they were word salad tossed with sine wave dressing. It spoke nothing to the suitability of a pure sine wave (in this case low impedance) as an AC source for audio equipment. You seem to know just enough to think you know a lot more than you really do. IMHO, posting what you did was an insult to all the audiophiles who are reading this thread.
You are listening to a Youtube video, of someone else's system, playing back on your system ... and you claim you are hearing subtle changes caused by an AC source connected to what looks like close to a 1/4 Mill of electronics, and, from what I can tell, you are not even using the same song for comparison. If I had that level of creativity I would be writing books, not in medicine.
Voltage changes can only induce noise in that they can induce currents. It is ultimately changes in current that one wishes to reduce to reduce noise. Every audio power supply has in the power path a diode (or equivalent) to rectify the incoming AC. The current only conducts for a short period of the sine wave, so the actual currents end up being harmonics of the line frequency as well as high frequency ringing due to component parasitics and inductance in the AC line and transformer. For the line frequency harmonics, the shorter the conduction angle for a give power draw, the higher the level of the harmonics. It is not unusual for tube amplifiers to have line noise harmonics show up in the output.
PS Audio's power plants have the option to output a modified sine wave (not pure), that has the benefit of extending the conduction angle with typical audio equipment power supplies. That will reduce the harmonics on the DC side of the supply, which can translate into reduces line harmonics reaching the output, and will generally allow components in the end equipment power supply to run cooler. It is absolutely NOT to color the sound. It is to remove color from the sound. Stromtank is not the premier manufacturer. You are Jay are claiming that. Show me some measurements that prove that. They don't have a modified sine wave, and their THD is about 10 times higher than the PS Audio units. You also have absolutely no idea what the output noise spectrum is of these units. @ricevs and his friend are convinced his Giandel inverters are better. Enjoy the Music proclaimed that the low cost Yeti 400, for powering front end equipment, was every bit as good as the Stromtank (and a small fraction of the price).
Your personal evidence? A recording, made of someone else's stereo, played back on your stereo, with that recording being done in 192kbps AAC at best. That is like diagnosing someone's cancer by looking at a picture of his cousin taken with a Kodak Brownie. Comparing to the playing the songs directly, there is high levels of noise pumping (AGC on the recording?), some added distortion, and as noted, fairly high levels of reverb at upper mid/high frequencies. If you think you are picking up what are likely to be differences not revealable by measurements in that total signal chain I am not sure what the point of this discussion is.
p.s. Jay appears to have 5 or so Stromtank videos. None that I viewed had the exact same song at the 0:00 mark and 3:00 mark. If they exist, feel free to repost links.
