This is one of many examples where tube testing requires experience to properly evaluate any tube. In this situation, using a tube tester would yield a completely wrong answer. These tubes were factory marked as E283CC, but are actually 12AX7A tubes. Hence, if you tested them in your tube tester using E283CC settings, you would […]
when E283CC tubes are actually a 12AX7 Read More »
I am frequently asked to explain what all of the “letters and numbers” mean in a vacuum tube number. In the early days of radio, tube numbers were haphazardly assigned to new tube types. As more vacuum tube types were developed, it became more difficult for technicians to recognize any fundamental characteristics about a tube.
RMA Tube Numbering Code Read More »
How to Use a Tube Tester… and Tube Issues (in General) by Bob Putnak, ©2010. All rights reserved. Last update: Jan 2014. Your tube tester is often the first test instrument that you reach for when diagnosing problems in tube gear. All tube testers are a compromise in functionality, compromise in accuracy, and none are
Tube Testing & How to Use a Tube Tester Read More »
Discolored getter flashing (brown or black marks) does not mean that a tube was used. This fiction is believed by both uninformed buyers and seasoned tube jockeys. This myth seems credible because some new tubes have perfect shiny mirror getter flashing; therefore the assumption is that brown or black stains in the getter flashing must
brown-black getter flashing does not mean ‘Used’! Read More »
Here is a rare tube — a Marathon MX-280 Globe #80 rectifier tube featuring MESH PLATES construction! Not only that, but each section tests very strong Emission, comparable to an NOS #80! In 18 years of collecting, I do not remember ever seeing another Mesh Plates #80 tube. Look at that Glow! You can see
Marathon MX-280 Globe tube MESH PLATE Read More »
