EJ Jurich
author of
Vacuum Tube Amplifier Basics
EJ Jurich
author of
Vacuum Tube Amplifier Basics
Born May 1945
Originally From Chicago
Profession: Radio Broadcast Engineer, retired
Started tinkering with vacuum tube electronics in 1955 at the age of ten. The tubes used were 35W4 rectifier, 12AX7, and 50C5 output tubes. These were mostly tubes used in AC/DC radios of the time. Filaments were wired in series and connected directly across the 115VAC power mains. The 35W4 rectified AC directly from the 115VAC power mains; there was no power transformer. This would mean working with a chassis where ground circuits connected directly to the AC power mains. Back then AC plug prongs were the same size, allowing a plug to be plugged into an AC outlet either way. Depending on which way the amplifier was plugged into an AC outlet, circuit grounds might actually be on the hot AC mains. The AC/DC concept was a throwback to an earlier time when some parts of a city might have DC power. By 1962 I was working with more robust tubes, creating a favorite stereo amplifier using 6CA7 output tubes.
In 1969, I developed an interest in radio broadcast engineering. Passed FCC exams and received an FCC First Class License. The first radio job was as assistant engineer at WROK in Rockford, Illinois. A few months later, I was hired by CBS in Chicago as a staff engineer. Stayed with CBS for three and a half years. In the summer of 1973, WROK was looking for a new chief engineer and was offered the position. Slightly more than forty years were spent working at various radio stations around the country as chief engineer. This includes Milwaukee, Miami, Mobile, Baltimore, Birmingham, Grand Rapids, St. Louis, and Kansas City. Engineering responsibilities included maintaining studio and transmitter equipment with transmitter powers up to 50kW AM and 100kW FM.
After retirement, there was more time to work on tube amplifier designs. In 2014, it was decided to write a book geared towards the electronic hobbyist. The original book was sold on Amazon as a Kindle format book. Later, a printed version was also sold on Amazon. The Kindle format was dropped because of flowing text issues. The quality of the printed books was not great: cheap paper and text that looked like faded gray. The print books were discontinued in the summer of 2024 while working on the second edition of the book. Writing books is a lot of work. In my case, besides writing text, a lot of images had to be handmade. I later started running the text through a grammar checker, adding extra work hours. Rather than write books, I will be doing what I like best, tinkering with circuits. If I have something new to show, it will be on this website.
A real picture of me will be up as soon as I get my professional photographer (wife) to snap one.