yes, I saw the post before this but I can't get to all youtube material from work, so I wasn't able to open it, and even then, you already admitted that it wasn't as good after the youtube compression anyway.
I can't say anything about the comparison between the behringer and the tascam because I've never owned a tascam unit (and never will). but I have owned a behringer mixer before and the mic pres on it were extremely harsh sounding, that's why I got rid of it.
I seriously doubt you'll get "warmth" from a 2 channel behringer premp. I could be wrong, but I personally would not spend money on a 2 channel behringer dedicated preamp if I were looking for "warm character" to add to my input stage.
the m-audio dmp-3 is a very good preamp for the money! but again, I would not recommend it to you for adding "warmth"!!! it's not a "warm" preamp, it's a "clean" transistor only pre!
http://www.sweetwater.com/store/detail/DMP3/ check out the reviews - the very first review is titled "Super Clean Preamp"
if you want "warmth" you need either a tube pre or a transformer pre. there are different types of those.
1) starved plate tube pre. this is a preamp which splits the signal and adds clean transistor gain from one path, and sends the other path to a starved plate voltage tube. you won't get gain out of the starved plate leg of the circuit, but it will add "tube warmth" which can usually be added in increments of how much is mixed back into the final output stage. these starved plate designed preamps are very affordable and a great way to add some "tube warmth" to your input signal.
these are the least expensive way to "warmth" in the path. look at an ART Tube MP Studio V3 for about $80 or Studio Projects VTB1 for about $150, or the one I have for starved plate and I really like is the ART TPS II for about $185.
2) a real tube preamp. these are "old school design" of using tubes for the actual gain stage of the amplifier. they are the best design for true tube preamp gain, but they are also expensive in the realm of home recording. they start at around $800. (look for a UA610 SOLO for about $800)
3) transformer designed preamp. there are many, many different "colors" and variations, with many different configurations of transformers on input and/or the output gain staging. different transformers and different designs of transformers will create different "color" to the signal. there are no real "categories" to put them in except some of them are "Neve clones" which they design them to be as close to a (famous) Neve 1073 pre as possible.
most of the transformer designed pres are also expensive for the home recordist. most start at $500 (and there are few in the $500 to $1k range) but there are a FEW "inexpensive" transformer pres like the Golden Age Audio re 73 which is a Neve 1073 clone that retails for $300. (I have one!) also look at the focusrite isa one for about $500.