Tubes, valves, hollow state, that's what they were called. Vacuum tubes have been around for a long time. Audion valves were invented in the early 1900's. Tubes became more common during WW1. Soon after they were found in many consumer products. Most of the public had tube devices such as radios, TV's, and hifi systems.
Our military and commercial industries used tubes for radio, radar, test equipment. They were used in mobile radio transceivers such as police and fire, and other communications equipment. Today, 2021, they are mostly obsolete except for a few products like guitar amplifiers, hi-end hifi tube amplifiers, and amateur radio transmitters. There are a few other uses, mostly obscure.
Back in the 50's and 60's they were in every electronic device. When transistors made their public appearance in the 60's, tube usage started to dwindle. Most consumer gear all went to solid state devices. Tubes required a lot of current for the filaments and high voltage circuits. During the 80's tubes all but disappeared from the public. No more drug store tube testers. Televisions used to be all tube and in the 70's most were now transistor.
Tubes are still being made overseas in Russia, Holland, Japan, and China. US manufacturers abandoned all tube manufacturing except specialized high power usage. High power Amateur Radio transmitters used tubes but even these are being phased out for high power solid state FET devices. High power AM and FM broadcast transmitters still use tubes but with new technology these are being obsoleted too.
Russia never shut down their tube manufacturing plants. The Russian military still use tube equipment because they feared damage from an enemy EMP attack.
Good quality guitar amplifiers still being made today have tubes and sometimes a mix of solid state electronics to get the "sound" desired. Back in the 60's, tube guitar amplifiers were being made by the thousands. Today, used guitar amplifiers bring a good price on the used market. It is claimed that they give a softer "warm" sound not heard on transistor amplifiers. Tube amplifiers are more forgiving and can take a lot of abuse without damage to the tubes. There are a few niche products that consumers desire that use tubes due to the "warm" sound they provide.
Some common tube numbers you may come across in most consumer products are 12AX7, 12AU7, 6V6, 6L6, 6BQ5, 6C4, 5AR4, 5U4, 5Y3, 6146, EL34, EL84, ECC83. Years ago just about everyone had a radio and it had what was referred to as the "All American Five" because it had five tubes in it. They had 50C5, 35W4, 12BE6, 12BA6, 12AV6 tubes.
Many tubes for sale may be marked "NOS" which stands for "New Old Stock" which means they were manufactured many years ago but never used and usually in original boxes. Tubes may last a long time but should be tested to make sure the vacuum seal hasn't been compromised.
Copyright ©2021 Rick C. Version 0.12 Feb 15, 2021