Can Luxman 509u drive JBL Ti5000

Im newbie
I have just bought Luxman 509u to drive the vintage JBL Ti5000 6OHM/90Db (http://www.thevintageknob.org/jbl-Ti5000.html) . However the volume needs to put at nearly 10 oclock to feel relatively loud enoug.

Does it mean that Luxman 509u is a bit weak in term of driving strength for JBL Ti5000?

Many thks