The ornamental design for a ledlampbase, as shown.
FIG. 1 is a perspective view of a LED lamp base showing our new design.
FIG. 2 is a front elevational view of the LED lamp base.
FIG. 3 is a rear elevational view of the LED lamp base.
FIG. 4 is a left-side, elevational view of the LED lamp base.
FIG. 5 is a right-side, elevational view of the LED lamp base.
FIG. 6 is a top plan view of the LED lamp base.
FIG. 7 is a bottom plan view of the LED lamp base; and,
FIG. 8 is similar to FIG. 1, showing the LED lamp base being mounted with three LEDs and an envelope, wherein the LEDs and the envelope are shown in broken lines for illustrative purpose only and form no par of the claimed design.