CLAIM The ornamental design for an audio signal amplifier, as shown and described.
Description:
FIG. 1 is a perspective view of the top, front and right side of an audio signal amplifier showing my new design;
FIG. 2 is a top plan view thereof;
FIG. 3 is a front elevational view thereof; and,
FIG. 4 is a bottom plan view thereof.
The dot-dash-dot broken lines represent the boundary of the claim. The evenly spaced broken lines show portions of an audio signal amplifier that form no part of the claimed design.
