Jig

I’ve finished modifications to my test jig to allow the testing of the 6BQ5/EL84. It’s really a shame that so few other 9-pin power pentodes use the 9CV pinout. The 6CW5/EL86 is the only other really common one.

Now that the Source Selection Preamp writeup is complete, I took a little time today to prepare for another effort.

Today I was once again reminded of the perilous state of human fallibility and the risks of personal hubris. The cost of today’s lesson? One ruined KT-88. And a little smoke in the office.

I took some time this week to get several coats of oil on the chassis for the Dual Triode Test Station. Even though I’ve already used it for the mystery tube investigation and to compare some 12AU7s, it’s good to have it finally complete.

Back in November, in my post concerning Tubes and Tube Testers, I talked about how I was not really a fan of generic tube testers. In that post I sited a statement from the RCA “Receiving Tube Manual”, RC-30, about testing tubes.

The tube tester cannot be looked upon as a final authority in determining whether or not a tube is satisfactory. An actual operating test in the application will give the best possible indication of a tube’s worth.

So I thought that as a simple demonstration I would collect some data from a couple of tubes; one new and one rather ‘used’. The results are really kind of surprising.

Ignoring the wood chassis for the time being, I made significant progress on the triode test jig today. I just thought I’d post a quick update. Parts are now mounted and some wiring is underway.

I’m working on two projects simultaneously right now; the 6AS7 SET and the Triode Test Jig. In the last couple of days I’ve made progress on both. However now I appear to be at an impasse.

When I talked about designing the Dual Triode Test Jig in the “More on Tube Testing” post I mentioned an indulgence. Well the results are in.

Ever since I completed the Optimization of the 6V6 SE-UL I have been saying that I was going to do the SE-UL optimization process for more tubes. So yesterday I finally started to make plans.