I agree with Mike, that's a great idea. If you really need a buffer to drive the amp, an active preamp will show you. If you have one lying around, easy to stick it in there to hear how it affects the bass transients. Cabling is not concern, any old crap will show you wnat you need to hear. You might find that a dedciated preamp might offer more subtlety than a mod driver stage.
Turn the volume pot all the way up to get the input resistance as low as possible and use the pre's VC. Sorry, I can't remember whether you said you had a pre on hand.
Marriage of Figaro? That is a fun show!!
Rich
