Can anyone help me ?
I recall reading something about using a pair of DI's either end of an XLR and converting impendances or something....What's the trick?

Al

The trick (and it's pretty simple) is pretty much just what you described. Plug the guitar into a DI box, so you have a balanced signal coming out. Run your XLR to wherever it needs to go. On the other end, plug the XLR into a second DI (which would probably need to be a 'passive' box). Then take a 1/4" line out of the unbalanced connector on the second DI and run it into the amp. Of course, the second DI is actually wired "backwards", i.e., the XLR input is being routed into what is normally an output, but if you're using a passive DI it should just work.

You may also want to check out the Little Labs STD.