Tube testers

"...was wondering if others had the same experiences as @russ69 with sudden tube failures even when they tested well..."

Well, I’ve had brand new rigorously tested tubes that were bad right off the start. Mostly noisy preamp tubes in hi gain circuits. Also tubes can fail an infant death after just a few hours of use. Or they can degrade slowly and at different rates. In my experience one tube will sonically fail without warning and will need to be replaced, testing a failed tube is fruitless. I buy new production tubes that have been burned in and tested, no need to do that twice, then I run them until they fail, sometimes spectacularly!
Culling tubes that have not had good screening or used tubes is not always successful judging by the number of unhappy customers with some tube retailers. 

"...I can't imagine having to replace one tube at a time when something is not sounding right to find the bad one..."

That is exactly what you will do when testing tubes. Listening is often better than measuring. 

’something very good’.

then you have to find one that has been restored by a pro.

Since inheriting tubes in 1973, I check my tubes annually, before thanksgiving, ready for the holidays

My experience over many years:

1. stand in front of a monster tester at an electronic store checking everything from Fisher President II: fm tuner; am tuner; tape deck; two multiplex added; master control panel, two amps. legs, back and feet hurt, grumbling line behind me. maybe need 2 tubes in the whole lot.

2. wife got me a small portable tester of my own, wonderful. accurate? compared a few good and bad with the monster store unit, same results.

3. bought big jackson, had tech check the small one and it. they always agree.

4. stopped using the big jackson, use the small portable for myself and friends.

5. test new tubes when received, test annually, test when a problem occurs. found a few shorts; found a few weak; found a few ’unmatched’.

I recommend you and anyone who has tube equipment get a simple small portable tester. make sure the manual, real or download is available.

then, if you truly get serious, go for ’very good’. do real research and get one overhauled by a pro.

Yes.  While I have personally been fortunate in that I've never had a tube failure, including tubes I've been running for 15 years or so.  But, I know of plenty of instances where a tube suddenly failed after testing strong on a TV-7.  It is just something that happens occasionally and I don't know if any tester would be able to predict that result (the Amplitrex, because it tests at high plate voltage and dissipation might cause a failure in a tube ready to blow).  But, at least a tester will give some indication as to how much life still remaining in the cathode.

a tube will test fairly strong over the vast majority of its life and will only start to test weaker at the relatively shorter end of its life.  On a tube that tests strong, most testers are showing you that it is still in its middle life, but, they will not show you how close they are to the declining part of their life curve.  Hence, most tube testers are sort of rough screening devices--better than nothing and something that affords one some peace of mind. 

The very first tube tested on my Amplitrex was a rectifier that a friend wanted to have tested because it came from a dubious source.  It tested zero voltage drop in both directions  (dead short).  It was far better to know this from a test rather than in the amplifier circuit.

@charles1dad   This was the feedback I was hoping to get from others and was wondering if others had the same experiences as @russ69  with sudden tube failures even when they tested well.  Much appreciated.

"An old tube can measure perfect and be at the end of it’s life the next day."

That’s interesting. In well over 25 years of owning tube components (Friends also with similar tube equipment backgrounds) this hasn’t been the case. Test results correlated well with tube performance and tube longevity.

I’ve not known anyone who have had tubes test strong-very strong and then rapidly fail. @russ69 was this a rare or common occurrence?  As others have mentioned above the Amplitrex is an excellent unit.
Charles

uTracer3 for $247 vs Amplitrex for $2760 (as of yesterday). I don't think it has anything to do with fun, simply budget. You pay a hefty premium for convenience.

Having 19 tubes in my system I can say having a tube tester does comes in handy.  I can't imagine having to replace one tube at a time when something is not sounding right to find the bad one. 

Vinylvalet,

The tube tracer looks quite interesting, but it appears to be a pretty complex and tedious process (I suppose it is fun to some people).  The Amplitrex, if attached to a computer, will also trace the tube.  I lasso like the fact that it does not require calibration.

I admit that there is some fun in using something like the TV-7, but also some terror concerning mis-reading the table or incorrectly setting the dials which could mean damaging the tube and getting a bad reading.

i still have my military/hickok tv10 - good tester, will last longer than its users for sure... straight read on gm (no need to consult the conversion formula like the tv7’s require) - very useful in matching small signal tubes

http://www.vacuumtubes.com/TV-10.html

op needs to understand that most testers of this ilk will not/do not properly test power tubes such as kt88's at their normally high operating levels in actual amplification circuits... 

Used tube testing is a crap shoot. An old tube can measure perfect and be at the end of it’s life the next day.

Is this true?  I always operated under the assumption that tubes rarely die quickly and instead, they just slowly get duller and duller.  I realize a tester may not always be definitive on how much life is left on the tubes and that your ears really are the best measure. Although over several years you may become accustomed to the very slowly diminished SQ so the degradation of SQ may not be immediately apparent over time. 

My approach has been to replace my tubes after several thousand hours and see how the new tubes compare.  If there isn't much if any difference then I put the old ones back in and milk out the rest of the life.  But I always thought it might be handy to have a tester just to get an idea whether the tubes may have much life left.  Perhaps a tester for that purpose is worthless?

@stereo5 $2675 in 2010.

There wasn’t any price listed on the web site. I don’t want to call them but does anyone know the price, +50-?

Transcendent Sound made an excellent tube tester kit; discontinued many years ago but if you can find a working unit used, I highly recommend it.

With that said, I hope to replace it with an Amplitrex unit, hopefully one day soon.

For a whole lot less money, this little fella looks pretty cool:
https://www.dos4ever.com/uTracer3/uTracer3_pag0.html

I had a quality tube tester, really didn’t use it much. I bought new tubes from well known suppliers that have already done that work. Used tube testing is a crap shoot. An old tube can measure perfect and be at the end of it’s life the next day. Unless you are in the business of selling tubes, skip it and just buy good tubes from good suppliers.

Here is the one Larry mentioned.

http://amplitrex.com/

Probably the best is the Aplitrex tube tester.  It is extremely easy to use (no looking up tube types to set operating parameters), it gives both real numbers (emissions, transconductance, noise) and the standard values for each of these numbers for the particular tube type) and it tests at full power (which means its values are conservative).  The big downside is that it is quite expensive.