The date of entry into the Celestion log book is 6th May 1966 (see Michael Doyle – ‘History of Marshall’ book – p137), however they were definitely made earlier than this.
Amp manufacturers switched to ceramic speakers, mainly because they were cheaper than alnicos, but they also proved to be a perfect match for the edgy, over-driven guitar sound that was emerging at the time. The ceramic magnets used on Celestion greenback speakers came in four main sizes.
The larger magnets have a higher power handling because they can absorb more heat.
As such it is an absolute classic speaker and can be heard on countless albums.
Famously used by Angus Young and an important ingredient in Van Halen’s “brown sound”.
Ceramic speakers (aka ‘greenbacks’) first appear around late 1964 to early 1965.
They have a slightly more aggressive tone compared to the alnico magnet speakers.
*Power handling increased by 5 watts around late 1967 due to a change in the voice coil design.
The T1134 model was probably the first ‘G12H’ speaker Celestion ever made.
According to the Celestion log book, it was first introduced in Nov 1964 and has an impedance of 10-12 Ohms.