Using the preamp/gain in the R-09? I would strongly caution against it. Chris Church has package deals at a discount for both his mics and preamp.
http://taperssection.com/index.php/topic,80054.0.html
The mic in analog stage of the R09 is top-notch IMO. (Mic input, low sens, agc off.) I've used it with a wide variety of gear including: AT822, Sennheiser MKE2, AT853, Church Cards, AKG CK91/93, and ... Beyerdynamic MC930. All sound great. (Visit
www.soundmann.com for samples if you don't believe me.)
The only fault is if you have low input levels (eg., acoustic recording). In that case self-noise is a problem and you need an external pre. For low input levels, I've been using a minidisc (HiMD, PCM recording), and this works well too.
To improve the sound of the R09 you would have to step up to a "professional grade" preamp like the Grace V2 or SD MP2.
Richard