Vacuum Tube tester? - Page 1
Forum section: electronics / beginners

author: MrZwing
author_rank: Regular Contributor
timestamp: February 04, 2015, 06:13:14 am
content: I'm planning to build some different circuits with vacuum tube's in the future an thought having a Tube tester would be nice to have.Now I wonder is there any recommended tester out there that are in the "start-up" price range or if there is some way to build one. an are they still built by enthusiasts or should I look at the vintage type?/MrZ

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 04, 2015, 12:50:07 pm
content: Most any basic "good/bad" tester is simply a diode mode (emission) tester. They may also do grid leakage and shorts. You can test for a weak cathode by reducing heater voltage by one step, and more thoroughly test grid leakage (if so equipped) by increasing heater voltage by one step.The really fancy ones (including the Hickoks that go for >$300?) perform these tests quantitatively (rather than qualitative good/bad), and also perform transconductance and perhaps other tests.If you don't mind spending the time, you can also set up a breadboard to do the same. For transconductance, simply set up the device at the datasheet conditions, feed in a small AC grid voltage (maybe 0.1V), and see how much AC plate current comes out. The load resistance should be relatively small, a fraction of the plate resistance, to measure Gm directly without interference from plate resistance (which of course is more important for triodes than pentodes).Tim

author: albert22
author_rank: Regular Contributor
timestamp: February 04, 2015, 02:46:33 pm
content: Something like this may be useful for your project:http://www.dos4ever.com/uTracer3/uTracer3.htmlSimilar DIY tube curve tracers can be found on the web.

author: Electro Fan
author_rank: Super Contributor
timestamp: February 04, 2015, 08:23:08 pm
content: As a frame of reference for what's out there you might look on eBay. Search on tube testers in general; take a look at Hickok - a lot of people think they made excellent tube testers - among the very best. You can get some ideas about what features you might want to build into your DIY project, or depending on your location you might find a unit in good condition that will meet your budget. A lot depends on the particular types of tubes you are going to be using/testing as well as the particular tests you want to run (such as transconductance as mentioned by T3sl4co1l). The 539C is an all-time favorite (perhaps exceeded only by the 580A); probably out of your budget unless you get lucky but it would be a good study reference for nearly every function and spec ever built into a tube tester. One other thing - be very careful poking around with tube circuits - can be lots of voltage in there.

author: Seekonk
author_rank: Super Contributor
timestamp: February 04, 2015, 09:19:29 pm
content: Quote from: albert22 on February 04, 2015, 02:46:33 pmThanks for that. Don't think I will ever need more than my Jackson, but that was an impressive read.

author: MrZwing
author_rank: Regular Contributor
timestamp: February 04, 2015, 09:44:03 pm
content: Quote from: albert22 on February 04, 2015, 02:46:33 pmHmm I will take a look at it.Quote from: Electro Fan on February 04, 2015, 08:23:08 pmCould maybe try and find a Service manual and see if i can get a schematic to reverse engineer and maybe improve with modern components to make it smaller. but that is a long term project for a newbie like me but always good to have some proper challenges in life.