I was asked by reader Brett, regarding Jackson 648, why is the setup data different for 6EU7 (“65XZ”) vs 12AX7 (“35WX”)? Answer: This is yet another example of the inconsistency of tube tester setup data. It goes even further, as 7025 has ~slightly~ different settings (32WX) vs 12AX7 / 7F7 / 6681 / 6SL7 / […]
Jackson 648 setup data 6EU7 vs 12AX7 Read More »
A reader asked me why 12AX7 were testing weak on a BK 600 tube tester, but testing OK on a BK 707 (top panel Gm test). The 600/606, and the bottom panel of BK 700/707, will overdrive a 12AX7 at plate(cathode) current levels that a 12ax7 tube is not really designed to handle. [FYI –
why 12ax7 may test weak on BK 600-606 Read More »
Back in stock (VERY LIMITED AVAILABILITY — only 2 available). Voltage pot for Sprague TO-3 cap tester. NOS NIB USA. Get one while you can. At least 1 of them is available as long as this notice is still up. If for some reason you have problem using the Paypal button, email me. This post
Sprague TO-3 voltage pots in stock Read More »
A quick example where a Sencore Mighty Mite (here, a TC28) finds a defect in a 12FV7 that the BK 707 (in the Jet-Test upper panel) cannot find the defect. If you read my previous blog post, the test setup data for 12FV7 is faulty. With my corrected setup data, this defect is now found.
Mighty Mite finding more shorts Read More »
BK 700 or BK 707, the setup chart data for 12FV7 tube uses Jet-Test socket #8. This configuration is highly flawed for testing 12FV7 and can damage the tube. Furthermore, the meter reading you would get is meaningless due to how severely overdriven the tube is being operated at. In the photo below, you will
12FV7 faulty setup data for BK 700-707 Read More »
