If you insert the active cicuits between the PU selector and the output jack, they will always be in the signal path.
Check out Guitar Nuts http://www.guitarnuts.com for some Strat-related tips that you can adapt to an LP.
Check out StewMac http://stewmac.com for more tips and any hardware you might need.
Skull Dragon; An LP with split humbuckers wired in parallel instead of series yields a sound fit to make Fat-Strat players weep in frustration! Check out http://www.dimarzio.com for the schematics.
[Edited by Lordathestrings on 12-02-2001 at 02:13 PM]