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 Warm Audio WA73 is a great pre, and almost ended up being the preamp I chose. It sounds amazingly large, it has limited but great sounding tone options, and heaps of warm gain. I ended up going for the ART PRO MPAII, because it has that comparable warmth, but with two channels and more options.