Omg, what a setup. Thanks for the link, will take more time for this article.This person makes a list of valid reasons to why this could be the case
https://audiowise-canada.myshopify.com/blogs/news/can-a-mojo2-sound-better-than-a-dave-yes-heres-how
There are a gazillion filters there, more is better?
When I bought Sbooster with its own filter, it said to monitor for adding extra mains filters, some might make things worse in combo.
My rebelamp did not benefit from mains filter, I tend to believe it was better off.
A filter is a filter? I've few euro ones from amazon, but also expensive Puritan boxes.
I just hope he didn't overdo things (in good fate) at the expense of Dave.