In the 1980s Marshalls JCM800 line started out using G12-65 Celestions in the 1960 4x12 cabs. In the mid 1980s they changed to mostly G12T-75 though. These two speakers are very different but both classic in their own right. I compare them using a Marshall Superbass with a Gibson SG and a Squier Telecaster. This G12-65 is from 1983 and the G12T-75 is from 1990.