Every Sunday, we plug our acoustic guitars and electronic drums into a Direct Box.  This direct box then let's us plug the 1/4 inch cables into the XLR floor jacks because the direct box switches from a 1/4 plug to the always popular XLR plug.  In geek-speak, "line or instrument level unbalanced signals to low-impedance balanced signals."  Direct boxes run from a few dollars to a few hundred, depending on what's inside the box. 

The Whirlwind IMP 2 Standard Direct Box is an economical direct box. Input is Hi-Z bridging. Output has a ground lift switch.   The box is riveted together, not glued like some brands. 

One owner said "I have had several of this items for 7 years and they still have not failed. Have been able to handle the road abuse and still kicking."

A DI Box is something you might use every day.  It's small.  It's not filled with LED lights and switches but that doesn't make it any less important.  Check out the Whirlwind IMP 2 Standard Direct Box if you need to add or replace any direct boxes.