I did a search on this and found nothing, since I hope to soon be in possession of an Ampeg B25B head for the second time in my life (the first one got sold out from under me), I am looking to see more about when various cosmetic changes started taking place on that era of heads (for instance, the B25Bs started with two switches on front, then went to three, then went to two plastic switches, etc.), so if anyone has a photo of their Ampeg tube head they'd like to show a picture of, please post them here! And if you know the year, please make a note of that as well!