Nguyen787, why not try a preamp that is not passive. I would try the Coincident preamp first before getting rid of the Frank's. I think you are going the wrong way.
Anyone have Coincident Frankenstein amps?
I'm looking for a nice 300B based amp, and this is at the top of my wish list. Anyone have any input on the performance of these amps? Any other brands you would suggest? Just want to try a 300B based amp to switch back and forth with the 845 based amp I have now. Thanks!