Tube tester...anyone own their own?

It depends on how serious you want to get.

If you’re really serious get the Amplitrex AT1000, about $3000

If you can live with less precision and control but want a modern computer type tester the Maxipreamp 2 is about $1,000. It will not test power tubes.

If you want a general idea if your tubes are good or bad and are reasonably matched get a home grade Hickock or TV-7DU for a few hundred $. You will not get repeatable results from these testers. Each time you test a tube you will get somewhat different results. These were basically designed to be good/bad testers for the TV repairman to bring to your home to replace tubes in your TV, console stereo or radio.

The lab grade Hickocks, 539C, 752A and others will give more accurate results and more control over the testing parameters, but will cost more than home grade and require quite a bit of learning to use them properly.

Also, the 6DJ8, 6922, 7308 family stresses out most home grade testers except the TV-7 family and you cannot get good results from most home grade testers.  The results just go off the charts.

I am not an expert and if any of the above is incorrect or incomplete, please correct me.

If you want a general idea if your tubes are good or bad and are reasonably matched get a home grade Hickock or TV-7DU for a few hundred $. You will not get repeatable results from these testers. Each time you test a tube you will get somewhat different results.

FWIW I haven’t found that to be the case with my Hickok 800A. In fact on a number of occasions I’ve recorded measurements of a given tube, then repeated the measurements after many months of light to moderate use, and obtained essentially the same results.

I’m very careful, of course, to set the "Line Adjust" and other adjustments on the machine ("Bias" and "English") accurately, and to allow both the tester (which contains one or more tubes) and the tube under test a sufficient amount of time for warmup.

Best regards,
-- Al

Al, thanks for your experience. What do you mean by essentially? I mean that you may not get a radical difference but you won’t get the same reading either.

I’ve been told by Roger Kennedy that the spec for a new (and there aren’t any new ones anymore), calibrated Hickock home type tester for Gm is +/- 15% That means that two testers both within spec can have a 30% difference measuring the same tube, worst case.

It’s also necessary to remember that most of these testers contain tubes inside the box with no ventilation, so how long the tester has been on affects the results. I’ve been told to never leave them on for more than an hour.

The Maxi-preamp 2 tester has an adapter for testing 6DJ8 family tubes but it still has the problem of the tube overloading the tester.

@mofimadness  That's an interesting option. Any idea as to what that sells for? Also, I wonder how accurate that Orange unit will be with power tubes? 
A few years back, I took an ARC amp to a local tech who tested the 6550's that the amp utilized. I thoughts something was wrong as the amp was noisy in one channel...and the tubes were not new. He tested the 6550's on his Hickok and pronounced them healthy. Turns out that they were anything but, so after a near melt down..and a full tube replacement, the noisy channel issue was solved. 
Since I am now using KT150's in my amps, I would like suggestions as to an amp tester ( besides the pricey Amplitrex..which I am sure is excellent!) that can accurately test these tubes.