||Reinhold Bogner, since 1989. North Hollywood, California, USA.
Dating Bogner amps
“Unfortunately there is no uniform way to find out what year the amps were made.
First the amps had serial numbers, then from1992 amps had a serial sign, from February 2005 on they have serial numbers again. Only sure way to determine the year is to call or email Bogner and we can look it up. There might be dates on certain parts if the amps are opened up to identify the year.” [Source: Jorg, Bogner Amplification ,email 12/8/2008 ]
Bogner amp forum
Image of Bogner Shiva model from 1992 – with serial sign from eBay:
Image from Bogner Ecstacy 100B eBay – a modern version: