Dairy Giant, please understand that no offense is intended toward you. But, the fact that a question like this is even being asked indicates to me just how screwed up the priorities are of many home recordists. In particular, there is WAY, WAY too much attention being given to the supposed "need" for outboard preamps. Can an outboard preamp improve your recorded sound? Absolutely. But should you be worrying about that, when you're just trying to make some demo-quality recordings in your home studio? Definitely not. ESPECIALLY at the budget range that you're talking about. Dude, you're talking about microphones in the $100-300 range (US dollars). Both the AT2020 and the ADK Vienna are fine mics that give way more value than we have any reason to expect at their prospective price points. However, let's keep in mind that we are still talking about very, very inexpensive microphones here. The thought that somebody might take a mic budget of less than $300 US and consider cutting it down even FURTHER, to allow for the purchase of a mic pre (which would, necessarily, be a very cheap one at that budget level) is just plain silly.
Here is how I suggest that you proceed: When you've got a budget of just a few hundred dollars, spend it ALL on getting the best microphone you can get. When you get ANOTHER few hundred dollars to spend, spend all of THAT money getting another quality mic - the best you can afford. And so on. As you build up your mic collection, don't forget that you need to ALSO budget some of your money for quality monitoring and room treatment. AFTER you've taken care of all the problems with the sound quality of your recording and monitoring rooms AND you have assembled a nice collection of processors and mics (let's say at least one or two dozen quality mics), then you need to spend some time learning to use the equipment that you have. Figure about a year or so for this.
Now, at this point (but definitely not before) you MIGHT need to upgrade your mic pres. But then again, you might not. You will need to figure out what is holding you back from making better recordings. It might be that your mic pres are not up to snuff. More likely, there is something else, such as the quality of your converters or your studio monitors that is keeping you from making the best recordings you can make. Remember that you're just making home demos; you don't need to make recordings that compete with the best of the big label releases. Also keep in mind that, even those inexpensive stand alone recorders by Boss and Yamaha are capable of making very, very good quality recordings - certainly good enough for the purposes for which you are using them. Even cheap preamps are adequate for this purpose. If you can't get to that level of quality, then the problem is probably in lack of experience with your gear, or any one of many, many other problems, besides your mic pres.
I see this sort of thing all the time on this board. People with only a half dozen cheap microphones are out there shopping for a new mic preamp. It's totally ridiculous! This notion that people who are at the most basic, beginner level of recording need to worry about buying quality microphone preamps is just plain goofy. At that level, you are better off spending your money on just about ANYTHING else, and taking the time to learn to use the equipment that you have. Get good mics. Get good monitors. Tune the sound of your room properly. Get lots of experience with your gear. And then, once you have developed a good understanding of recording techniques, and have learned to hear where the problems are in your recordings, you will KNOW when you need new mic pres.
Brad
its getting lotsa love on OSXaudio.