Here is something that you will not see everyday, an NOS NIB NEW Globe-style Arcturus blue-glass 071A audio output tube. Type 071A is also known as 71-A, 71A, 171A, 271A, 371A. This tube has the star-logo on the top of the glass bulb with 071A inside the star logo. Engraved base reads “ARCTURUS – No. …
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 …
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. …
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 …
I am frequently asked by B&K and Hickok owners to explain how to replace a #83 tube with a solid state version. This question is popular because #83 tubes are scare and expensive. Other benefits are increased reliability (no tube to wear down), less heat generated inside the tester case, and less load on the …
