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 ART Pro MPA II is the the biggest of pre on the list (it also has dual channels). This is the preamp I ended up choosing. I didn't really expect to like it so much, because it is the cheapest on this list, but it is amazing. It's the only tube driven preamp on this list, and it sounds really good. Especially on vocals, it gives warmth that is not too smooth, with a crystal like edge on it. But also on bass, where it gives the sound that nice tubey edge.
Where the rest of the preamps sounded different from each other, but stayed very much in the same region, the ART Pro really stood out, in a positive way. The mid/side, DI and tone shape options make this on of the most versatile preamps out there. I read that the soundfloor can be lowered even further by changing out the tubes, which I'm looking into now. Definitely recommended!