The Japanese-made Fenders do have some slight serial number differences (typically a "J" serial number prefix). I believe this was a mistake on Fender's part using the same prefix for both U. Below are some examples of letter prefixes used in recent serial number schemes.Japanese Serial Numbers on Peghead Decal Note the lack of S, E, N series.
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.The simplest vacuum tubes resemble incandescent light bulbs in that they have a filament sealed in a glass envelope which has been evacuated of all air.In March 1985, CBS sold Fender to a group of private investors.The serial numbers do not reflect this change - Fender continued to make instruments using existing serial number schemes.
The new Fender did not acquire any physical assets of the old company, just the name "Fender".
Hence during 1985 to 1987, production of Fender guitars was only done in Japan, while USA Fender created a new factory in California. BUT note that the "E" and "N" series does sometimes appear on "made in Japan" models. In any case, if it says "made in Japan", then it is... Fender has recently (in the last 20 years) introduced LOTS of different serial numbers schemes, depending on the country the Fender was made (USA, Mexico, Japan, Korea, etc). Sorry, since I do not collect new Fenders, I don't really keep track of these things.
However, tubes are still used in several specialized applications such as guitar amplifiers (also called a valve amp outside the U.
S.) and high power RF transmitters, as a display device in television sets and in microwave ovens.
Vacuum tubes, or thermionic valves, are arrangements of electrodes in a vacuum within an insulating, temperature-resistant envelope.
Although the envelope was classically glass, power tubes often use ceramic and metal.