I've got the 22 and 12, had the 10 for a month or so. Similar voicing in the line, oversimplifying: FA-10: I believe this was the first, and plays no particular favorites between bass\mid\treble in it's voicing. "Special skill" in the line is it puts out a lot of power....this is a good juice-hungry cans choice. FA-12: Highlights the bass, slightly warms and thickens the FA-10 sound. "Special skill" is fully balanced. FA-12S: Single-ended out only version of FA-12...cheaper. FA-22: Highlight mid's\dynamics.....takes the house sound a bit faster\more detailed, but also a little thinner in tone. All above is of course "to my ears"..... more experienced ears mileage may vary. The " line tone" to me shades neutral with a bit of warmth. I've been comparing this week to the Liquid GX I got last Saturday. It's like the LauX and the Jot 2 had a baby, while the Lyr 3 with a JJ tube watched from the closet. The LauX has a bit deeper soundstage with a real impressive rich delivery......the FA-22 rocks a bit harder\faster....doesn't have the hint o' roll-off that I get with LauX. I think the FA-22 plays nice with the Bifrost 2 and the LauX is more a DAC 2541 partner (for me). At the under $1k level, I think the Flux amps are very solid.