This video shows the testing of 6J1 and 6AK5 vacuum tubes on a vintage Chinese GS-5A tube tester. The Chinese manufactured 6J1, which is a substitute for 6AK5 tubes, is a well made tube - in my opinion, one of the "gems" among vintage Chinese tubes.

If you are interested in GE 5654W (which is a premium substitute for 6AK5 and 6J1), please follow this link to my amazon store.

http://www.amazon.com/Matched-5654W-Fully-Tested-Vacuum-Replacement/dp/B01BFJDTW0/ref=sr_1_1?ie=UTF8&qid=1460687157&sr=8-1&keywords=5654w