Although the envelope was classically glass, power tubes often use ceramic and metal.
The electrodes are attached to leads which pass through the envelope via an air tight seal.
Even at we struggle with keeping a correct amp and speaker model overview.
There are also exceptions to the rules where Fender delivered non-standard speakers in special orders, Christmas campaigns etc. See our Buyer’s guide to vintage Fender amps for a guide and picture gallery of the known original speakers in the blackface and silverface amps.
View the underside of the chassis (flashlight helps alot)look for the reverb driver trans.
Our Buyer’s guide to vintage Fender amps explains in detail how you can date your amp by looking at serial numbers, tube charts, transformer codes, speaker codes, Fender logo, etc.
Lots of different speakers were used in the blackface and silverface era Fender amps.
When hot, the filament releases electrons into the vacuum: a process called thermionic emission.
Whether it’s a vintage amp or a recent model such as this Fender Pro Reverb, hum can have several causes.