" the best Tweak ever in the entire audio industry"

Results are mixed.  Judge for yourself.

https://www.youtube.com/watch?v=nrqVYE4_v1M&t=128s

@jastralfu Very good.  You got good ears and educated enough to use headphones. 

How many of you hear what @jastralfu heard?

First off, the YouTube film that Fosi put forth is meant to assist people in making their buying decisions. If you’ve already purchased the op-amp and are using it, there’s no need to watch the film. Of course, an educated audience should be aware of the lossy format used by YouTube and understand that the quality of reproduction depends on the recording itself.

The big picture is that not many hi-fi gears allow for opamp swapping. Buying low-fi or mid-fi gear and upgrading it with better opamps doesn’t necessarily transform it into true hi-fi. For example, Fosi + SS2560 / 3602 <> hi-fi. Price-wise, these op-amps add up to a total that outweighs the cost of the amp itself. Sounds funny, doesn't it?