A little bump for this thread. I had both the JVC Flats and Yuin G2A. I was modding the Yuins for better portable use; headband and pleather pads. I used the Flats pads on the G2A for more bass punch outside. Inside, I realized the pads made the Yuin's a bit thicker and less detailed. So I decided to see what the Flats sound like with the Yuin/KSC style pads.
These are the exact same ones from earlier in this review. I got them all in trades with ljokerl including the parts express for the headband.
The result is that the much cheaper Flats sound very similar to the Yuin. I would say at least 90-95% as good. Quite hard to A/B as it takes a few times to get a hold of the differences since they are so close.
I would say the Flats have a slightly shorter decay of notes and the notes sound a bit sharper while the Yuin has a longer decay and they hold bass notes a bit longer. So, the Yuin might have the slightest bit more bass and the flats make detail a slight bit easier to here. Neither was any better overall, IMO, just slightly different sounding.
I felt there was no point in having two extremely similar sounding phones so I sold the Yuin since the JVC's slightly quicker decay appealed to me.
So, in short the Flats are cheap and can be cheaply upgraded to be even better! A throw in, in a trade, that ended up being a real keeper!