I had posted sometime back that I liked everything about my (then) new Focusrite 18i20 except that the preamp gain was not adequate for my Cascade Ribbon mic. I tried running an Aphex preamp as a pre-preamp, which worked... but seemed lacking.
I finally bit the bullet and purchased a Cloudlifter CL-1 and couldn't be happier. The CL-1 is an extremely clean in-line preamp that is powered by phantom power. I now have gain to spare and the Cascade seems to have benefitted sonically too -Now I think I need to work on improving the sound of my room.
PS - the Fethead sounds like it may do the same thing for less, but the design of the Cloudlifter seemed superior. I was able to get an additional $10.00 off at GC by filling out an online survey which gave me a $10.00 e-certificate.