First a little background. I had been using a Hartke 5000, a Hartke 4X10 and an Eden 15. I then bought a GK 700RBII and a GK2X10. I'm pushing the 4X10 and the 2X10 with the GK head. I was talking to a guy at guitar centerand he asked why I wasn't using the Hartke to push the 15. He said I could run out of the GK from the effects send into the effect return of the Hartke, to power the 15 and still get the sound from the GK. Can this be done like that?