testing tubes in the bin?

[luthierwnc]

Hi all,  I've got maybe 50 tubes in the bucket that are pulls, were in sold amps or who knows how they got there.  I've kept them because that's what people like us do but I'm hesitant to use them because they could range from great to dead-shorts.  A couple years ago I asked a couple tube sellers if they would test them for a fee and was told, in no uncertain terms, that they wouldn't risk their nice testers on my POS tubes.  I can see their point.  Some are really obscure but perhaps a half dozen are old EL84s which would be convenient for a build I have underway.

At any rate, what is the budget way to see if these tubes are worth keeping.  If not, should these be turned in to a site that takes hazardous waste? 

Thanks, sh

[thetragichero]

have a local ham radio club? i bet somebody has a tube tester. i take my organ pull tubes to a local electronics surplus store that has one of those "drug store" tube testers from yesteryear

any good tube tester should test for shorts so i wouldn't see even a bad tube damaging a tester. my guess is that the tube sellers just don't see enough of an ROI testing your tubes?

[Latole]

Most tube tester can't do a good test for Power tubes. Tube tester may show you tube is good and they are not.

Power tubes need to work "hard" to see if they are good, most tubes tester are like testing a car in a idle on a parking lot, not on the highway.

Tube tester don't tell you if a tube is microphonic

[dragonworks]

I  have seen chess sets made out of tubes, pretty cool. I have a couple of boxes full and am giving it some thought. As a retired CNC programmer I can write a program for the bases and have my buddy make them for me.

[HotBluePlates]

Most tube tester can't do a good test for Power tubes. Tube tester may show you tube is good and they are not.

Power tubes need to work "hard" to see if they are good ...

I don't agree with this statement, at least in the way it is said here.  Plenty of tube testers can show if a power tube has good Gm at a reasonable voltage.

The better statement would be, "an Output Power Test in an actual amp circuit that compares the tubes being tested to a benchmark-power-output of known-strong tubes is a better test for output tubes."

That is, do whatever preliminary steps to make sure there are no catastrophic faults, then check power tubes in a power amp circuit to see how they perform in actual use.

[Latole]

That is, do whatever preliminary steps to make sure there are no catastrophic faults, then check power tubes in a power amp circuit to see how they perform in actual use.

That  is always what I do

[HotBluePlates]

That is, do whatever preliminary steps to make sure there are no catastrophic faults, then check power tubes in a power amp circuit to see how they perform in actual use.

That  is always what I do

By applying an a.c. drive signal?

[Latole]

With no signal and with AC signal.

I alway found with tubes are good or not