I use a Saffire interface by Focusrite. I plug in the guitar to the inputs, and monitor in real time from the Saffire outputs.
The echo (in the track inspector) feature does not affect what I hear one way or the other. It only makes a difference if and when I use something like guitar rig...(a software guitar amp sim) but other than that I hear exactly what I put into the front end of the SAffire... and the DAW does NOT have to be running. The "echo input" is set up and controlled in the Saffire's control panel software which starts up with the computer and the Saffire.
My website & music:
www.herbhartley.com MC4/5/6/X1e.c, on a Custom DAW
Focusrite Firewire Saffire Interface
BMI/NSAI
"Just as the blade chooses the warrior, so too, the song chooses the writer "