Ahh… shame.
I see the OP has Excel2016 for the Mac and that does have the CONCAT function.
I can't think of an array formula to do this off the top of my head, but the following works:
Code:
=DEC2HEX(CODE(MID(A1,1,1)))&DEC2HEX(CODE(MID($A1,2,1)))&DEC2HEX(CODE(MID($A1,3,1)))&DEC2HEX(CODE(MID($A1,4,1)))&DEC2HEX(CODE(MID($A1,5,1)))&DEC2HEX(CODE(MID($A1,6,1)))&DEC2HEX(CODE(MID($A1,7,1)))&DEC2HEX(CODE(MID($A1,8,1)))
but you lose all simplicity and speed.
If you:
=SUMPRODUCT(DEC2HEX(CODE(MID(A2,{1,2,3,4,5,6,7,8}, 1))))
you can see all the results in the SUMPRODUCT dialogue box. Perhaps you can think of a way.