Description

This is an NOS Ampeg-branded Sylvania 7591A power tube in its original box. It tested 100% on my tube tester, consistent with its condition. There is a small white mark on the plastic base where it stuck to the paper inside the box during years of storage. This tube is from the estate of a technician who worked with a well known North American classic rock band in the 1970s and 80s. Most of the parts I found relate to either stage audio, signal routing/switching, or CNC programming. About testing: The tubes were tested on a consumer-grade tube tester which has been calibrated according to its instructions. After one minute of warmup each tube is tested for shorts, leaks, and for general function, and the function test provides a 0-100 (bad to good) metered score. I record this for each tube. In cases where a tube requires two tests I have used the lower of the two scores. Though this tester has proved accurate and reliable enough for testing tubes I use in my own personal devices, please note that this is not a military or industrial grade tester and the results should be considered approximate.