I recently decided it was time to upgrade from the built in preamps in my Focusrite Sapphire to a 'real' external preamp. My budget was about 600 EUR. Afer a LOT of online research, I narrowed my options down to 6 preamps, in roughly the same price range. The preamps were:
ART Pro MPA II
Warm Audio TB12 Tone Beast
Black Lion Audio B173 Preamp
FMR Audio RNP 8380
Warm Audio WA73
Focusrite ISA One Analog
As I will be using the preamp mostly for vocals and bass, I tested both those signals.
I plugged my Ibanez 600 in passive mode into my BSS DI, into the preamp. For vocals, I hooked up my SM7B straight into the preamp, into Logic X. The results:
The FMR Audio RNP8380 is a dual channel preamp in a super small case (especially compared to the others on this list). It sounded great on vocals, with a lot of smooth, round gain. On bass I felt it lacking, clipping more easily, and sounding dull. Also, it doesn't have a lot of options. But it plays very well with an SM7B.