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the 250th tube tester thread - help me choose

sancho22

sancho22

AK Subscriber
Subscriber
Hi all
I red up at AK and many other sites. It seems that depending on planned use, budget, etc. there is no clear consensus.
all testers seem to have some limitations. Amplitrex AT-1000 seems to be the easiest and likely the best for home use but really very expensive.

I am talking ONLY about fully serviced and flawlessly working testers below.
From vintage testers the Triplett 3444a seems to be tied with Hickok 539c 9a/b sort of close) and tube sellers (eBay customers too) like / accept TV 7 U/D.

However IF I am planning to just test my power tubes in my fairly nice amp collection (EL34, EL84, 6L6, 300b, 2a3, etc) and preamp/phono/small tubes a few others could play:
- Heathkit TT-1
- Hickok 752
- other TV-7 models

So would the 752 or TT-1 or lesser TV-7 models do the trick? Which one is easiest to use?
Thanks in advance
L
 
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There is a very interesting tester comparison somewhere on the web. Can’t find it right now. I think it was JAC music. The uTracer came out tops by a good margin.
 
curve tracers really are awesome when it comes to testing and matching tubes. It gives a full picture of their characteristics, not just a single operating point snapshot like everything else does.
 
If you want to test tubes for personal use and a TV-7 fits your price range, I can recommend that. Not sure there is any such thing as "fully serviced and flawlessly working testers" that are not expensive (and they are also heavy so include shipping). I own a restored and calibrated TV-7B and got lucky with local pickup where the guy spent 30 minutes making sure I knew how to use it. (It was non-obvious, at least to me, at the time.)
 
My Hickok 752a (as well as the 752) tests both sides of dual triode tubes (12ax7, 12au7, etc.) without having to reset the selector switches for each side - very convenient if you want to test a bunch of those types
 
I have a Utracer, and it is a fantastic piece of equipment. Perfect for signal tube, not so much for power tube as it can't get the plate hot as in real condition.
And you have to assemble it yourself.

I have a TV7, nice tester, but it is expensive, require restoration, and overdrive the small signal tube. But it's a nice one.

I have a Sencore MU150, a perfect emission and transconductance tester, but is often require restoration (I have a thread on it and posted the PCB files for printing), but this one does not test older tube 4/5 pins as it was intended for TV repairman.

So you need a digital for signal tubes, and analog for power tubes. This is becoming an expensive journey, close to the cost of an Amplitrex.

Look also for https://maximatcher.com/
They are nice as different tester for different tube types.
 
Heathkit TT-1A is a decent tester and user friendly. Most of them need service and calibration but are fairly easy to work on.

Maxi-Matcher makes great testers too.

I use a Kaye Audio Labs tube tester. It tests small signal tubes and does a decent job for what it’s designed for.
 

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Hi @sancho22 ! :)

I had a Triplett 3423 :

1701422582481.png 1701422766361.png

The Triplett 3423, 3444 - those measure proportional Gm - all suffer from a design flaw which gave inconsistent Gm measurements. No possible cure, as it is inherent to the design of these instruments. Some Weston models are also based on the same Gm measurement system and are also unconsistent.

I had a Hickok 752a :

1701422842797.png 1701422867182.png

This is a really worthwhile, reliable, dependable instrument, though not as good as the 539C for tube flaws identification (leaks, etc...). It uses the well-known Gm bridge measurement principle patented by Hickok.

I never had a Heathkit TT-1, but as far as I know, it has the same Gm measurement circuit as the Triplett 3423 / 3444 , and it suffers the same Gm measurement inconsistencies...

1701423193488.png

The Hickok TV-7 is less modern than the 752 / 752a, and was more military / checking orientated use :

1701423376119.png

If it was me, between all those models you name, I would go for the Hickok 752 / 752a, the most interesting, documented and consistent of your list.

Today, my bunch or tube tester is reduced to 4 main complementary items :

G3zlNb-my-tube-testers-15-10-2016.jpg


The Hickok 539C is the best for tube troubleshooting identification (leaks, shorts, life, microphonics, etc...).
The METRIX 310CTR is the best for tube measurement and matching, working with official datasheets, not proprietary charts.
The NRI 70 is the best for tube quick sorting "dead or alive".
The Hickok 600 is interesting because it measures AVG Gm, and I draw a rule for comparing to official datasheets.
The Seco GCT-5 is "supposed to check grid N°1 current", but I never could measure any grid flaw with it... :biggrin:

T
 
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gadget73 said:
thats George Kaye ? I think he was the guy who designed my Moscode preamp.
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It sure is. It tests for noise, gain and output. Can also be connected to a scope and have a signal put through the tube. It’s pretty decent. However I still think the best tester is my ears and the circuit the tube is used in :)
 
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uTracer, Hickok 605A, B&K 707. My uTracer will handle output tubes up to 400VDC on anode, so I have found it very useful for testing and comparing output tubes. Brice, not sure what you mean about not getting the plates hot enough--thermally?

605A very useful as long as you understand what the Gm tests represent against the bogey values in the test roll. 707 is quite useful for quick and generally reliable testing of many tube types and results generally compare well with the Hickok and the uTracer. "Pessimistic" on some tube types, though.
 
Yes Dave.
Utracer send pulse to the tube, and measure it, over and over very quickly. It's good as you can't red plate a tube by mistake.
But for power tube in real condition, the tube plates are hot. The Utracer is not capable to get them hot, therefore the result is not accurate.
 
can't test it for sustained emission in pulse mode, but a power output test will do that. I suppose you'd have to build a test circuit using a couple of regulated power supplies to duplicate datasheet conditions and confirm that it makes rated output into the specified load. Not hard on a technical level, just kind of annoying to do in a practical manner.

or just stuff it in the amp its supposed to go in and make sure it does what it ought to do. If its weak enough to matter you'll know it pretty quick. I've got a pair of absolutely whipped 6CA7 tubes around here somewhere. They bias up just fine, but they make about 5 watts before falling apart. Good tubes in the same amp make an honest 40. Have a set of somewhat tired but not useless RCA 6bq5 that make 11 watts, where a good strong set will make closer to 14 in the same amp. Not weak enough to retire them since they sound fine.
 
IMHO, there's a lot to be said for measuring tubes in the circuits they're used in. You can also buy a lot more tubes for the price of the better testers! I use a cheap Eico 667 to see if they're alive and it predicts performance fairly well most of the time. The final arbitrator is the circuit the tube is installed in.
 
ConradH said:
IMHO, there's a lot to be said for measuring tubes in the circuits they're used in. You can also buy a lot more tubes for the price of the better testers! I use a cheap Eico 667 to see if they're alive and it predicts performance fairly well most of the time. The final arbitrator is the circuit the tube is installed in.
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Word.
Shameless when I was a kid post ...
we ran down to Thrifty Mart or wherever and the testers just said red or green. No one knew anything about Gm or microphonics or matching tubes or anything.
 
Jalousie said:
Word.
Shameless when I was a kid post ...
we ran down to Thrifty Mart or wherever and the testers just said red or green. No one knew anything about Gm or microphonics or matching tubes or anything.
Click to expand...
This!!! My tester is for fun! My ears do the real testing :)
 
Ok so the maxi match requires two testers which brings the bill to 2k
Amplitrex almost twice as much
Serviced TV7 around 1500
752 about half of TV7- looks like a no brainer?
 
Indeed.

Gadget, the Utracer use a capacitor as a reservoir that it loads at a given test voltage, then switch it to the tube and measure the current. All that is a very short time.
It works very well for pulse, and have enough energy to create sufficient current at a given voltage, quite impressive. But for very short time.
It does not have a real power supply to generate a continuous current at 400V to heat a power tube plate.

I believe the Amplitrex does it, and a crazy German opensource tester, very complicated, but very good. That's the 2 digital tube testers I know capable of testing power tube under "real" condition.
 
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