What I find surprising is that the key ingredient, the TPA3255 chip from TI, has been around for… 8 (more?) years. Why did it take so long for somebody to figure out the successful recipe?
Kudos to Fosi Audio for listening to the users, and applying good engineering rather than chasing some esoteric BS audio paradigm.
The PFFB technology used by Fosi has been around for a long time. However, due to patents, this technology could only be used by certain manufacturers. Therefore, even TI, which developed the TPA3255 chip, was not allowed to provide technology using PFFB.
However, that patent expired about three years ago(?), and anyone can now use PFFB. However, each company had been manufacturing products without PFFB for a long time, and it was difficult to incorporate PFFB right away.
I have been proposing to various companies to adopt PFFB because even after the patent for PFFB expired, no products using PFFB were released. As a result, Fosi's first product is the V3 Mono.
Even though the technology was well-established, it was still unknown to the company, and it must have been difficult to incorporate it into their products for the first time. However, the number of products that use PFFB should increase in the future.