The electrodes are attached to leads which pass through the envelope via an air tight seal.
On most tubes, the leads are designed to plug into a tube socket for easy replacement.
After reading Teagle and Sprung's excellent Fender amp book, I took them up on their challenge that maybe someday someone will compile enough serial numbers so that Fender amps can be dated that way. I contacted several Fenders collectors and dealers who were kind enough to supply me with data.
I turned to the Internet to do some more networking which resulted in a major turn of events as I met two individuals who have become instrumental partners in this project: Greg Huntington and Devin Riebe.
According to the Superior Music website that was mentioned here on another thread, it looks like it points to a 1970 amp.
The serial number stamped in the chassis is A23373-107.
Most of the amps were finished in a "gray crinkle" finish.
The finishes were baked in the Kauffman family oven.
They are all very rare today and few have survived.
Additionally, Greg and Devin also had data that they had been collecting from Fender amps for years. Everything is confidential, we don't make record of who owns what amp in the database.
We combined all of our information into a computerized database for this project and for the past 18 months have been slowly (sadly, very slowly) gathering information that we collect ourselves as well as from other people. What we need is the following: 1) Model name 2) Model number on the tube chart 3) Date code letters on the tube chart 4) Speaker codes (if speaker is original) 5) Transformer codes (if the amp doesn't have date codes on the tube chart) 6) Cosmetic features (flat/raised logo, tweed/tolex, blackface/silverface, rough/ smooth blond tolex, white/skirted knobs, TV-front/wide-panel, etc.) One very interesting and very important factoid has surfaced regarding the date code letters on the tube chart.
The first of these amps were the K&F models, which were produced between 19.
The original Fender amps were tube-powered and the company also started producing solid-state models in the late 1960s.