Purifi Class D: Junk?

Example,
i had not listened to the stereophile first test disc in 10 years.  However, my system 10 ears later was more revealing than that older system except for the fact that the original system used super highly modified original Quad electrostats.(modified by me....the most extensively modded Quads that i have ever heard of).  When I played the disc 10 years later it did not sound right at all....the orchestra, the air, the bell ringing in the backround, the guy singing in Hebrew.....just not right.  So, I removed the midrange from its box and put it on top of the speaker and propped it up with a paper back book underneath (no baffle) and changed the xover on the woofer so it now went to 300hz as i knew the midrange driver on an open baffle would not do anything below 300hz.  After listening......most all of the difference from what I had remembered 10 years before came alive.  Still not quite as good as the old super modified Quad....but now very close....the reverb was going on for ever......before it was all blunted with the midrange in the box. 

Yes, indeed you can remember what something sounded like 10 years before.  Anyone can do this.....with an open mind and open heart.

In a few more days the Weiss opamps will be at 200 hours and ready for evaluation. Also I have the amp running through a 500 watt balanced isolation transformer along with the DAC and pre; I wonder if there could be any current starvation going here.

Linear power supplies on amplifiers draw current in large peaks, much higher than the average power current draw. A 500W isolation transformer will act like an inductor with a current limiter. It may be better, it may be worse.

The VTV amps use switching supplies and idle at something like 30 watts. If you have reasonable efficiency in your speakers you will not even use 100 watts on peaks. However, all transformers sound different from each other and most isolation transformers sound like transformers.....slightly slow......even 3000 watt Topaz isolation transformers can mess with the sound in certain ways. Every thing messes with the sound. Right now I am running my super modded VTV right out of the wall (power cord hardwired into the wall....yup, no joke). I want to get a 2000 watt low distortion pure sign wave inverter to run the amp. I am currently using a 400 watt inverter on my digital front end....giving super sound......really nice to get off the grid!

http://enjoythemusic.com/magazine/equipment/0119/Goal_Zero_Yeti_400_Lithium_Portable_Power_Station_R...

The reviewer is now using a 1200 watt Yeti on his Pass X250.8 along with the 400 watter on his front end.

No, it is not, especially with the Hypex amps. The input is meant to be driven by a very low impedance source.

Once again, you have no idea! 
The input impedance of the NC500 Hypex is 2k across the band, and can be driven by any buffer from a source that has 50ohm or less output impedance and the voltage gain needed to give you the max level that you need listen to. Once again, you have no idea!!
I'll try to get my friend who heard it yesterday to post on it.