I was a voracious Ampeg collector for sometime.Ive had many.many over the years.Although I havent made any acquisitions in about 5 years.I have three EARLY B-15 heads,that have been sitting around gathering dust for a long time.I always had all my stuff serviced by Jesse Oliver.(You know who he is right?) Id like to sell these heads,but cant for the life of me remember how to translate serial numbers into production dates. I remember something like "first digit is decade,second is year,third digit is month,and remaining ones are the unit number produced that month" Can anyone help me? Oh yeah,mine are #065691,#039674,#001664. Thanks for any help.