I am looking to buy a microphone preamp to improve the sound of my dynamic microphones. Right now I am considering the ART TPS II and the Presonus DP V2. The ART model has been highly recommended by some friends, but no one has heard the DP V2 yet.
The only criticism that I've heard on the ART TPS II is that I will most likely want to upgrade the tube immediately to get a more rich sound.
The only information I've heard about the Presonus DP V2 is that the preamps are the same as on Presonus high-end mixers which are good but "not so great".
If anyone can provide some insight I would greatly appreciate it. The preamp would be used for vocal recording mostly with Shure SM58s or a Heil PR40.
They're both "cheap" preamps in the same class and neither is a "real" tube preamp -meaning neither is an actual high-voltage design and are probably more sold-state in nature. The tube is more for distortion color (marketing speak is "warmth"). As someone who has used preamps from both companies, neither is going to really outshine the other when it comes to sound quality.
I like the build and component quality of the Art stuff a little bit better than Presonus. The Art TubePAC pre I have uses a stepped gain control and has a more linear range. The Presonus pres I have used (on their digital mixer and their D8 pre) are conventional pots with more log taper which is a little bit of a pain.
Specific to your needs: the Art has variable impedance which is a tool meant specifcally for messing around with the tone of dynamic microphones. The Presonus doesn't have this BUT... most people I know who have a pre with variable impedance don't use it much after their first experimentation with it.
You may want to look at the Art MPA, too. And depending on what you're using already, you may just want to spring for a decent condenser microphone, instead.