Advice on a tube tester

Well I just got kicked off Facebook for the weekend so I'll probably be active here.  Not sure if that is a plus or a minus for Audiogon.  😎

I'm looking to buy my first tube tester.  I want to be able to identify bad tubes, verify readings on "NOS" or "used, measures like new" in tubes I buy, and I need to sell off a bunch of tubes and I'd like to be able to test them before I sell them.  Selling a bad tube, refunding the money, leaves me out shipping, a lot of work and 3 good tubes in limbo. 

So I'm looking at a B&K 707/747 or a hickok 539A or similar, mostly just based on what I see that fits my needs and seems to be $500 or less.  I see tested and calibrated tube testers for $1500 on ebay but I think I can get by for a lot less.

Tubes I have to test are 6l6 series, EL84, OA3/4, 6922, WE396, KT88 and maybe a few others.  it would be nice to test 300B/350B tubes but I think most testers doen't do that. 

So I'd appreciate guidance from people who have been testing tubes for a while.




Super risky buying used tube testers.  Once in a while a really nice one pops up that has been freshly serviced but it’s rare.  

Just about every eBay ad says clearly , no returns and many say powers up , not tested.   I was fortunate to buy a mint Hickok 800 that I saw work.   When I received   It I tested several tubes that were Amplitrex tested and my results matched those numbers closely.  I consider myself one of the lucky ones.  Most need service 




look for recently calibrated tv7 or tv10 - i have a tv10, which is a militarized version of the hickok, allows for direct reading of tube mu (transconductance), whereas the lower testers tv7 and equivalents require a translation table to get the figures

i would think good ones go for a grand or more, maybe even 1500 - thats the market...

I see tested and calibrated tube testers for $1500 on ebay but I think I can get by for a lot less.

You probably can- and it will need servicing and calibration. You may well spend the same amount as a result.

When testers like that were made they cost a pretty penny back in the 1950s. Imagine running a TV repair shop back then; this bit of test equipment was essential. If one were built on the same scale today and in the same manner, it would cost over $10,000.00.


Should have added that I intend to do any work it needs myself.  Never came across a machine I couldn't fix. 

I just don't want to get one that is shot.  I see tube testers that the seller tested several tubes on to confirm it is working.  or are selling their spare that they use and confirm it works.

Calibration I can likely do myself on most of them.



If I did not see a video of mine in use, with 6 v power and 12v preamp tubes I never would have taken the chance.  Plus it looks like it belongs in a museum but that doesn’t mean anything other than someone took care of it.  It suggests a hobbiest used it and it wasn’t the shop workhorse. 

remember everything had tubes back then.  Most of these testers have seen heavy use and it shows.  

Contact Paul Hart.  He is one of the foremost experts on calibration, repairs and selling used testers direct in the states.  He can give you a complete rundown on on the various testers and their limitations.  He convinced me it wasn’t worth buying a tester in my situation since I’m not a volume buyer/seller.  Good luck with it all.

Tube testers aren't very accurate at measuring the life of a tube, so you may still get some returns if using a tube tester.

@oddiofyl That's a beauty.  And I agree with your advice.  Loose sockets can be a problem with well worn testers.

@tksteingraber I would probably agree that I don't need one.   It is consistent with my lab scientist nature and I-build-thing mentality to want one.

@invalid I agree the data is not all it is cracked up to be but I see lots of instances where it is of use to me.  

thanks all for your help.  


Just remember, most are pretty crappy.   Nice ones cost $$$ but are worth it 

For checking if a tube is bad or not the tv-7 ( i had one in excellent condition), tv-10 are perfect for the job, most likely they would require calibration but are easy to maintain. For what matters most, to match tubes properly very few can do it.

Transconductance is not the way to match signal tubes but power ones.

It depends how accurate you want to be as i understand your tube menu varies. Would it be better to chase a modern tester that can do both?


Thanks @petg60 .  Which TV-7 did you have?  Do you know what the differnce is between the TV-7 A/U, B/U, C/u and D/U is?  

I had the 7B/U, the only one different, if i am not wrong, was the 7D/U which had an extra range (F) for higher transconductance tubes. The other difference is that the later ones had more ferrite beads attached to the wires going to the tube sockets, thus eliminating oscillation (especially when measuring 6dj8 family tubes). 

Another nice feature from this family of testers was that you could test a tube for noise, as the tube could pass all tests (short, leakage, trans) but could be noisy on one or both channels.

It was pretty good and straightforward to operate.

Thanks @gregdude I've watched his good videos.  He likes TV7.

@petg60 thanks for the details.  Turns out the D/U version is specially changed to address 6DJ8 tubes--which is half the tubes in my favorite that would be worth finding.



If you want something more modern that doesn’t use 1950s technology and was probably made in the 50s, check out these people:


You’ll need separate testers for power and preamp tubes, which may give you more accurate readings. The cost for both the pre and power tube testers will be up around $2,000, but you should be able to recoup the cost when you’re finished with them.

They’re up in Washington so you can give them a call and judge for yourself if these are the right testers for you.


The Amplitrex mentioned in an earlier post is considered by some to be the best tester available today:


tksteingraber's advice to contact Paul Hart is spot on. He recalibrated my Hickok 600 about 2 years ago and did a fantastic job and gave me great advice to boot. Even if you're going to do refurbishment and recalibration yourself, he's a great resource.

My system is pretty much all tube, and owning a tube tester has made that so much easier, and allowed me to take chances on cheap untested tubes that turned out to be NOS testing jewels. The Hickok greatly increases my joy in this crazy hobby.

One caution based on experience: you can sell tubes that test great and you know are perfectly functional, and the buyer will still hate them because they were lousy in their system. Refund them cheerfully and chalk it up as a cost of doing business. Most will love them and the honest seller goodwill is invaluable.

Best of luck on your journey. It's worth it.

B & K suits my needs and passed cal….but for the good stuuf i trust Andy at Vintage tube services…and RAM….. rip Roger…you are missed.

My system is all tube as well.   What prompted me to buy a tester was actually the fact that I sent a NOS rectifier to the guy who built my amp.   I actually sent 2.   Unfortunately one was shorted and failed during the amp's burn in.   Fortunately for me , Matt over at Toolshed Amps is a good guy and replaced the damaged parts , a cap and PS at no additional cost .   After all, I sent him the tubes.  I didn't buy his basic tube set , I went NOS and WE 300b.

So the night he reached out to tell me I had a bad tube, I said that's it !  I'm buying a tester.   It took a while to find that Hickok but it arrived right before I got the amp.   

I figured if I'm playing with 4 pin antique tubes, NOS , and rectifiers I am a fool not to buy one.  I will never plug a tube in without fully testing for shorts, filament good, and Gm.   Turns out another one of the 6 NOS 5r4gy was shorted, fortunately that tester identified it and prevented a catastrophic failure.   Thing paid for itself one week into owning it 

@oddiofyl Thanks for the story.  I'm starting to play in NOS tubes too.  I have a bunch of not necessarily new but old stock voltage regulators I'd like to sort.  

I've looked at the Toolshed amps and they look nice.

Whick hickok did you choose?  




All good testers you mentioned. I have had a TV-7b and it was a fine well built unit. Currently using a BK 707 and love it. Design is especially great when testing multiple 9 pin miniatures such as ECC83, ECC82, and ECC81 etc. Have used a BK747 and would be my last choice of the lot.
Calibration of these units can be done yourself and is not terribly difficult. There is a wealth of information out there. I did both my TV7 and BK707. Try to find one that is in good physical condition that shows light use. Heavily used ones can have sockets that make poor contact and it becomes a lot of work to replace them, although it is doable. Found my minty BK 707 ON FB marketplace locally for $200 and calibrated it myself. Does all the audio tubes and was these guys were made toward the end of the tube era.




Very useful post.  I'm finding a lot of testers don't do the 9 pin minatures that were introduced with color TV so they are relatively new.  For the TV-7 you need the D/U.  for the 752 you need the A to test 9 pins. for the 539 you need the C.  the 539 tests each triode seperately so you have to test them twice.  It does a lot of testing but maybe more than I need.  The B&K 707 attracted my attention early and I'm glad to hear your views--from someone actualy using one he calibrated himself.  Fully agree on replacing sockets, can do it but do I want to?  

I've been up and down the scale on these testers a few times.  Right now I'm leaning toward the 707 or the TV-7D...probalby whichever one I find first in good condition at a reasonable price.  

If after using the tester a while I want more data, I can buy a high end Hickok then.


I have a Hickok 800 , it’s perfect for screening tubes and preventing your amp from being a “tube tester”.   It’s more than adequate and fairly accurate.   If I were buying and selling tubes I would get a 539 or military type Hickok

I just bought a new Amplitrex.  It is easy enough to use and "computer mode" greatly enhances the set of functions.  Not cheap but well worth the money.  That said, I sell a lot of tubes and this unit is sort of essential for me to be able to communicate with Jac Music.  

I love it when I can justify the biggest and the best but not being a tube seller (other than my excess) I can't really justify and Amplitrex.  

@verdantaudio Not sure what your relationship is with Jac Music is but I just boght a couple grand of parts and tubes from them.


I spent some money, but I quickly found what tubes were great, who to trust , who screwed me.   

The 800 will test my 300b ,205d , rectifiers, 12**7,  EL84 , EL34 , 6l6, 6922.   So for me it was money well spent 

I am an EML retailer.  I stock EML tubes when I can get them.  That is my primary relationship with Jac.  I don’t so too much more in terms of parts and transformers. 

@verdantaudio I'm hijacking my own thread here but as an aside, I'm having a new amp built with EML AD1s.  I found your website and see you carry them.  my builder bought my first set directly from Jac.


I don’t stock that tube.  Quicker getting them straight from Jac.  I might not charge you shipping.