Splitting mono guitar input into two channels.

[armstrom]

I'm building an amp head based on a 25W stereo Tripath kit (The AMP6-Basic from 41Hz). I'm trying to figure out which is the best way to split the input into the two channels. If I wire the inputs with a stereo jack then any stereo effects plugged in to the amp will output on discrete channels. Any mono plug jacked in will be split between the two channels evenly. My current plan is to build two preamps (one per channel) and simply tie one to each input of the stereo input jack.

Here's the question.. will I be providing sufficient input impedance to "load" the pickups?

The preamp inputs have a 4n7F input cap and a 1M input impedance. Should I raise the input cap to 1.5M so when "splitting" the input of a mono plug the guitar pickups "see" 750K? If a real stereo plug is inserted (either from a stereo effect like a chorus pedal or from a stereo guitar) then each channel will see 1.5M... Does this seem reasonable? Or should I just build the circuits as-is and see what happens?

Here's a link to the preamp stage I plan to use (times 2) http://www.diystompboxes.com/smfforum/index.php?topic=63479.0 I will be running it at 12V since I already use that to drive the power amp.

Any advice is much appreciated!
-Matt

[armstrom]

anyone?