Anyone Here Ever Purchased A Tube Tester?

I have a Hickock tube tester I bought years ago from Andy Bouwman at Vintage Tube Services.  He had calibrated it, which I believe to be important with the older testers.  In addition to the drawbacks that larryi mentions, another drawback to an older one like this is that it may not  work with some of the newer tube types like your 6H30 (or at least it won't show it on the tube types on the tester's table that you use to set the type), but it does work well with the types I used it for in the past.

The Hickock TV7 was one of the types the expert I talked to liked.  He had concerns with several of the people he used to calibrate some of the units he had, finding that the results did not quite match up with other testers.  I suspect he was more inclined to pick among the MANY TV7s he has that proved to give good results (test results matching up with performance of the amp) and not do much in the way of calibration.  

A young friend of mine has a TV7 that he recently had re-calibrated.  The person who did the work is a friend who knows his stuff who was somewhat reluctant to do the work because it is very time consuming.  When he got the unit back, he also got back a bag full of parts that had to be replaced--it seemed like a lot of work was indeed involved in calibration.  I have used the TV7 at my local area shop, but it is a bit of a challenge to do the settings based on the charts supplied (I need to triple check everything I do so I don't accidentally cook the tube).  The people at the shop have the settings memorized for common types and they zip through the settings.

One piece of advice, if you do a lot of testing, buy socket savers so that the socket that wears out from tubes being inserted and pulled out is that of the socket saver and not the tester.  I spoke with an old tube guy who said that even good sockets may start to go bad after 30 or so insertions--in the days before people went crazy over trying different tubes, 30 insertions probably meant more than 30 years of use, which is not the case today with some tube gear, and certainly not the case with a tube tester.

I’ve been into tubes for nearly 35 years and never felt the need. Sputter, as you described it occurs frequently and I believe caused by pin/socket connections, not bad tubes. I check my tubes and just wiggle the tubes a bit and it usually goes away. FWIW.

I also own the Amplitrex. It is pricey, but very easy to use and has been very helpful in sorting out the weak tubes. 

i use a lowly B&K but in your case, The ability to properly test the 6H30 is key. I would invest in a backup set from ARC including the key 6550 in the power supply of your DAC, it is way more life limited than the 6H30. Then find a reliable vendor / ARC dealer w tester and have them grade your old tubes.