Watch the A Form: Arpeggio online guitar lesson by Dave Celentano from CAGED Commander
Playing the 'A form' arpeggio grants access to the 'major 3rd' on the D string, which is unavailable in the 'A form' barre chord version. This shape is a bit awkward to play so try this fingering suggestion - use the ring finger (3rd finger) to lie across the D, G, and B strings for a triple string barre at the fifth fret. Try to keep each note separate and not bleed into the next by slightly rolling the ring finger from the D string, across the G, and to the B for ascending and in reverse for descending. Begin and end the arpeggio exercise on the lowest root (see attached tab chart).