Tube tester...anyone own their own?

@ the OP, if you are testing drivers ok, for testing output power tubes not really worth the money
Tube testers are old instruments, with degraded parts, right now Roger is trying to rebuild the transformer of a 752 A I sent him some time ago, Roger he is one of the best if not the best, very honest and straight person. With the tester calibrated and ready to go it is advisable to use a variac to supply plate current to the tube so the measurement is more accurate if your tester is old like most are.

Don expect you will be able to measure tubes with high precision, unless you spend a lot of money and time. I own a BK707 too and it is a toy it constantly drifts.

Not trying to discourage you but it all depends on what you want it for. Which tubes and amp / preamp will you be using? How often will you be measuring?

I've also owned an Amplitrex AT1000 tester for around 10 years now, and have found it to be completely reliable, accurate and easy to use. Yes, it is expensive, but well worth the money if you are a serious tube audio enthusiast. As mentioned above, a lot of very well known tube sellers are selling both NOS and new production tubes out there which often do not test anywhere near what they claim they do, and use old testers that give confusing results that they try to dupe buyers into believing they are getting more than they really are. Don't fall for the "platinum matched" scam presented by some sellers who charge a lot of extra money for their tubes, claiming that they match within a few percent of each other, when in reality, they are off by as much as 20 or 30%. 

I have a B&K Dyna-Jet 707 that has been an exceptional companion for over 40 years.( Thank you Dad ! )   Have local vintage guitar/amp shop that will calibrate when asked.  

I might have made one in Jr. High Electric Shop back in the 1960’s.

TV-7 D/U and sent to Daniel Nelson in Arizona for updates and calibration.  If you can find the original military headphone set for noise testing, that is a big plus.

Also have a Western Electric KS-15874-L2 otherwise known as a Hickok Cardmatic.

The TV-7 D/U still appears on E-Bay quite regularly.