Anyone Here Ever Purchased A Tube Tester?

A friend and member of my local HiFi Club has a substantial tube collection with items spanning two generations of collecting. 

A Calibrated Tube Tester is a important part of this enthusiasts activities.

It is great to be introduced to same era Tubes with usage life beyond factory spec' and almost perfectly matched in each half of the Valve across Valve Pairs or Quads. 

It is only through being introduced to same Brand Valve as per the above and then compared to same Brand valves with a reduction in usage life and a wider range in the readings across each half of the Valve, does one discover the real attraction of very accurately match Valves.

It is something quite special to experience a near perfect match array of Tubes. Having access to the Tube Tester for periodical readings helps greatly with assuring the optimised experience of Valves is being maintained. These Types are usually the Sunday best and lesser quality matches are identified do the daily grind/glow.

@mitch4t Tube testers will not find a sputtering tube. The best way to find it is to swap it with the other channel if that is possible, if not, with another tube of the same type elsewhere in your system.

It can also be a corroded tube socket as previously suggested, but IME your DAC is far too new for that to be an issue. The tube itself is far more likely.

I run dome very old tubes in my system.  Once every three or do years, I get brief sputtering or crackling sounds that then goes away.  I asked the builder about this and he said something inside the tube flaked off and fell onto the heater and the tube will make that noise for a few seconds or minutes until the flake burns up.  He said it is no big deal.  

I frequently blab about everyone who has tube equipment getting an inexpensive tube tester.

I bought this Accurate Model 257 for a friend.

It's results matched the results of my smaller model 157. My Model 157 always matched my big heavy Jackson, so I gave the Jackson to a friend who used to bring his tubes here.