Recommend a decent, reasonably priced tube tester....

[clay49]

Hi guys,

I'm looking to get a tube tester, now that I've been sucked into the black-hole of NOS tubes...nothing terribly expensive...let's say $50-$200 max. Used is fine...dosen't have to be new. What are the industry "standards" in this price range?

I realize that you can "hear" when a tube goes bad, but I'm looking for a little more precise diagnosis before I throw a $75- $100 tube in the trash.

Thanks!

[LowellH]

The Jackson 648 (try to get the solid-state -R or -S model) is a great value. The Eico 666/667 and B&K 747 testers are also good and in your price range.

Keep in mind that most old testers will require a little initial work. At minimum, clean all the pots/switches and I'd recommend replacing all the capacitors (usually just a couple).

It's also a good idea to replace any out of spec resistors before calibrating the tester (calibration guides for most testers are available online, if not in the tester manual).

[Prairie Dawg]

Originally Posted by clay49

Hi guys,

I'm looking to get a tube tester, now that I've been sucked into the black-hole of NOS tubes...nothing terribly expensive...let's say $50-$200 max. Used is fine...dosen't have to be new. What are the industry "standards" in this price range?

I realize that you can "hear" when a tube goes bad, but I'm looking for a little more precise diagnosis before I throw a $75- $100 tube in the trash.

Thanks!

It depends on what you're trying to do with it. If you're only interested in testing a basket of flea market hauls for dead ones, any old emission tester will probably be fine.

The Jackson 648 is a good tester but that's only because Jackson built pretty good stuff. It's not a mutual conductance tube tester. Tone Lizard's got some great stuff about tube testers.

http://www.tone-lizard.com/Tube_Testers.html

[Trout]

Originally Posted by Prairie Dawg

It depends on what you're trying to do with it. If you're only interested in testing a basket of flea market hauls for dead ones, any old emission tester will probably be fine.

The Jackson 648 is a good tester but that's only because Jackson built pretty good stuff. It's not a mutual conductance tube tester. Tone Lizard's got some great stuff about tube testers.

http://www.tone-lizard.com/Tube_Testers.html

Jacksons are great,

Another surprising quality unit that can be located cheap in Mercury.
http://www.tone-lizard.com/Mercury.html

I have a model 2000 and it is very flexible and accurate. These are sleepers as far as price goes. I grabbed mine for under $50.00 in a lot/pile of electronics stuff at an estate sale.

Bonus, it is also a mutual conductance

[clay49]

Thanks, guys...I must admit that I am a total novice at this, and really, I just want something that will let me know when the tube has gone below it's "minimum good" level...which, by the way, how do you know what those levels are (a catalog somewhere of listed values)????

[clay49]

Originally Posted by LowellH

Keep in mind that most old testers will require a little initial work. At minimum, clean all the pots/switches and I'd recommend replacing all the capacitors (usually just a couple).

It's also a good idea to replace any out of spec resistors before calibrating the tester (calibration guides for most testers are available online, if not in the tester manual).

I'd rather not have to rebuild anything...something that is useable right out of the box or in working order would be best for me....

[Stacatto]

You've got a challenge in the price range that you mentioned. A. Tube testers are going up in price as I write this. B. Ebayers -often- throw them up as powered up, but not tested otherwise, and not returnable. C. Emission testers are more typically found for the amounts that you listed. The Jackson 648 is desired by many though the later models like the 648S are preferred. They made the 648 for about 30 years. Visit the tone-lizard.com for details...

[Prairie Dawg]

Originally Posted by Trout

Jacksons are great,

Another surprising quality unit that can be located cheap in Mercury.
http://www.tone-lizard.com/Mercury.html

I have a model 2000 and it is very flexible and accurate. These are sleepers as far as price goes. I grabbed mine for under $50.00 in a lot/pile of electronics stuff at an estate sale.

Bonus, it is also a mutual conductance

the Mercury is one of the few mutual conductance testers that'll do compactrons-which is a good reason for having one. Jacksons are built really well.

Now for the real lowdown. I have an Eico 625 (inexpensive build it yourself emission tester) and my main Hickok 532. So. Idle curiosity enters into the picture.

I took and tested a known good 6L6GC on my Hickok. Carefully measuring the needle deflection with a protractor I then put this same tube into the Eico and adjusted the load control to produce the same deflection. Then, I went and tested about 12 6L6GCs on both, leaving the load control on the Eico where it was. You'd be surprised how accurate the results the Eico produced were.

As emission testers go, the Eico 625 is a good bet, as is the Knight KG600 series and the comparable Heathkit. They're all a little optimistic though, so you have to use some Kentucky windage in interpreting the results you get. Plus any Eico 625 has probably got enough Dakaware top hats to pay you back a couple times over.

[JlMMY]

Over the last year I bought 4 Vintage tube testers. I was going threw the same steps as OP but got caught up in trying to find one that was "mint". I bought one EICO 625, two EICO 667 and a Hickok 605. They are all mint. I sent the EICOs to Bill Waters aka "The Hickok Doc", as he is known on the ham radio forums. Buying a tester without having it professionally calibrated doesn't make much sense. I have since learned how to calibrate my EICO 667 so I am keeping them. He does give a certificate with each calibration but the cost is $100-150 per unit. I am happy to sell one of my testers. PM me if interested? I have a Hickok 605 that hasn't been calibrated but works and I have a mint EICO 625 with manual, certificate of calibration, new bulbs, the works. He even put a circuit in the tester so a bad tube can't blow the meter. If you decide to buy a tester on Ebay be prepared to shop for a tech such as Bill. I am happy to put you in touch with him as well. Buying a tester has been a huge help in getting the most out of my amp collection.

[Prairie Dawg]

Originally Posted by JlMMY

Over the last year I bought 4 Vintage tube testers. I was going threw the same steps as OP but got caught up in trying to find one that was "mint". I bought one EICO 625, two EICO 667 and a Hickok 605. They are all mint. I sent the EICOs to Bill Waters aka "The Hickok Doc", as he is known on the ham radio forums. Buying a tester without having it professionally calibrated doesn't make much sense. I have since learned how to calibrate my EICO 667 so I am keeping them. He does give a certificate with each calibration but the cost is $100-150 per unit. I am happy to sell one of my testers. PM me if interested? I have a Hickok 605 that hasn't been calibrated but works and I have a mint EICO 625 with manual, certificate of calibration, new bulbs, the works. He even put a circuit in the tester so a bad tube can't blow the meter. If you decide to buy a tester on Ebay be prepared to shop for a tech such as Bill. I am happy to put you in touch with him as well. Buying a tester has been a huge help in getting the most out of my amp collection.

The three testers I mentioned-the Eico 625, the Heathkit IT-whatever and the Knight KG600 series are all kit built jobs. You could either wire them yourself or pay a bit extra for the factory to prewire them for you. My preference is for the Eico but that's for the same reason I like Volkswagen Beetles and M1903 Springfield rifles-they're simple, repairable, and hell for strong.

This has a couple of interesting results. The ones that were wired by dear old Dad on the kitchen table that winter are variable in quality of assembly and sometimes may require a bit of rework. However, I have found a number of them that dear old Dad....well....made a few blunders with and gave up and on the shelf it went to sit until the estate auction 40 years hence. That way you get a new never used tester for a pittance.

On the subject of calibration of emission testers I would say it is of marginal utility, simply because there were no standards for a tube's ability to emit electrons, although as a general rule, the less they emit the less useful they'll be. Sometimes a tube will emit well, but all in one place on the emissive element, and the tester doesn't know the difference.

If there's anything to be done in that manner, I would say that making sure your meter reads correctly (sometimes they don't) replacing the few capacitors in the tester, and checking for drifted resistors would be about all that is required. If you did get the manual or you've downloaded it from the BAMA site and it does have calibration information, by all means check it out. B&K almost always provided calibration information so you can get an idea of what's required, often only setting the reject rate and the shorts threshhold.

In addition, the power transformers in the cheaper tube testers were marginal so you end up with insufficient voltage on the filament string if you're testing tubes that draw some current. So, what to do? Raise the line voltage with the rheostat to get it back to par? Nope-that's a global setting and it'll raise every voltage in your tube tester and throw your results out to lunch.

What you have to do is monitor filament voltage from an adjacent socket and raise the voltage on the selector to the next increment-usually 7.5v for a 6.3v filament tube. I do this regularly with my Hickok when testing 45s, but there I have to raise it to 3.3v to get it to test at 2.5v.

[clay49]

Okay, I'm officially in over my head....

[Rhomco]

In very good condition and calibrated. The first tubes I tested were a pair of 6L6 I had just pulled from an amp that sounded perfectly good. The tester showed shorts in the tubes. I'm not sure what to believe....my eyes or my ears
Rob