When I was considering one of these gain boosters several years ago, I
came across the results of some tests run by Jim Williams on a Fethead
and a Cloudlifter:
https://www.gearslutz.com/board/show...3&postcount=78
https://www.gearslutz.com/board/show...2&postcount=86
In another thread, he wrote of the Cloudlifter, "I did extensive Audio
Precision analyzer tests on those. They add 1 db of noise to the stew."
"EIN specs (if supplied) will tell you the base line. Use a Neve ring of
three and you get about -125 db EIN. The best designs can best that by 7
or 8 db. That will determine if a fet booster will help or not."
https://www.gearslutz.com/board/so-much-gear-so-little-time/1233178-cloudlifter-supposed-increase-signal-noise-ratio.html