Mike - the d5 has a great pre, I've seen it used as an outboard pre into a dat deck a few times.. nice improvisation!
Calico - I'm not an EE but there are a few engineer tapers here in denver (e-scott, richard campbell and todd ramsden specifically) and I've been trying to get them to build a preamp for a while now...
I'd love to see/hear your custom box. I wish that I had the skill set to pull it off myself! +T
I'd really like to get together with some electrical engineer types myself. I'm not an engineer, just a tinkerer, but I do have a basic understanding of electrical circuitry. I'm also in Colorado.
I'd be happy to share circuit designs. The microphone pre-amps I have made are all difference circuits based on op-amps. Pretty simple, just requiring an op-amp, some resistors and some capacitors, a project board, solder and wire. The hardest part is building it all into a metal box and keeping everything neat and clean.
I'd like to hear from more people who have done this. I know there have to be some great "homebrew" boxes out there.
It's funny, because I agree with EA, the starter of this thread, there are only a handfull of pre-amps we always see as sources. If you don't see V2/V3, Mini-me, Sonosax, mod-UA-5 etc... in the source you tend to assume it's not a high quality recording.
As I am going to try the Oktava MC012 mod next:
http://www.taperssection.com/yabbse/index.php?board=3;action=display;threadid=6603it'll be a while before I get around to building a new pre-amp, but I'd be happy to share my experiences and suggestions with anyone who is interested in tackling a pre-amp project.