JJ Electronic

JJ Electronic, s.r.o is a Slovak electronic component manufacturer, and one of the world's remaining producers of vacuum tubes. They are based in Čadca, in the Kysuce region of Slovakia.
Most of the products that JJ offers are audio receiving tubes. These vacuum tubes are mainly used for guitar and hi-fi amplifiers. In technical terms, JJ produces triodes, beam tetrodes and power pentodes. Double diode vacuum tubes for full wave AC-to-DC rectifiers are also produced. JJ also produces electrolytic capacitors for higher voltage purposes, generally for use in audio amplifiers. JJ also manufactures their own line of high-end audio amplifiers and guitar amplifiers. 
In 2015, the company sales amounted to EUR 8.5 million and net income came to EUR 3.8 million. Most production is exported to the United States.
History.
Before 1989, TESLA was the main Czechoslovak producer of electron tubes. While TESLA vacuum tubes were exported all over the world, and were known for their quality, the company did not survive the change of economic system after 1989 in combination with the downturn in the vacuum tube market. JJ Electronic was founded in 1993 by Jan Jurco, using the old TESLA machinery for the manufacture of vacuum tubes. Eventually, JJ Electronic started to produce their own line of vacuum tubes and electrolytic capacitors, mainly targeted at high-end audiophile and guitar amplifier applications.
Products.
Small signal vacuum tubes
Power vacuum tubes
Rectifiers