Tube Tester


After a lifetime of solid state equipment I have switched to tubes, my first choice in sound but had not wanted to deal with the extra upkeep in the past. What do I need in a tube tester and any recommendations for something around $150 with shipping? I am using a Unison Research Triode 25 Integrated Amp with a Black Ice Audio DSD Wifi Dac, so the tester will need to be able to test EL34. 12AU7 and 12AX7 tubes.

Thanks
mtloriginal
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Nobody "needs" a tube tester. As mentioned above, there are ways to get around owning one.
But, I have to say owning one is a pleasure. I happen to have one that has worked flawlessly for many, many years. Yeah, a couple calibrations by Daniel Nelson over the years were costly, but heck, I look at it like a part of my system.
 My system wasn't sounding as good as it should have a short while ago. The second tube I tested in my pre amp was right around the minimum reading. Changed it out  (actually I changed out the pair) and whallah, system sounded better than ever.
Also good for when buying tubes that are advertised with test results, you can compare. And I have had a couple tubes delivered to me testing bad right out of the box (one from a very reputable dealer, who challenged me at first, then admitted it was bad once he got it back). 
I don't think you really need a tester.  I own an Amplitrex, but, it is on loan to a friend who owns many more amps than I do, does repair work on the side for fun and can put that beast to better use.  Others, above, have given great advice about swapping tubes to determine which one, if any, are at fault, and good advice on buying reserve tubes; if something sounds off, just switch in reserve tubes to see if that resolves the problem.  
I appreciate everyone's comments.
 Millercarbon, I want to be sure I understand you correctly. If you swap sides are you listening for the sound coming out of one speaker to change as in left/right channels?