Suggestions for a valve tester

[Millay_2010]

Hi all, as the title suggests I would like to get myself a valve tester yet I have no clue what to get as I have never owned one before.

I am looking for something quite basic and hopefully not expensive that is suitable for someone who is still learning,.

What do you suggest and what kind of money should I be saving for one?

[FIXITNOW]

Basic and cheapest will possible be the AVO two panel, it's what I have but like most AVO units check the meter is good. Seem to make about the £100 mark on auction sites.

[snowman_al]

Sorry my answer is dumb, but sort of devil's advocte...

What makes you think you need one?
What valves do you want to test? What are you going to use it for?

Did you see this thread? https://www.vintage-radio.net/forum/...d.php?t=153836 It gives some valve tester names you can look up.

Then the cost depends on how much you can afford, the best are expensive. Cheap and simple are pointless...

Alan

[stevehertz]

If you dabble with stuff that uses valves, then in my opinion owning a valve tester is a great way to eliminate a valve or valves from a fault situation. First of all, ask yourself the question, do you simply want to know if a valve is serviceable, or do you also want to know more about its finite performance characteristics? In the case of the former I use and would wholly recommend a Mullard High Speed Valve tester, in the case of the latter there are many Avo models and many others too, all of which have their devotees as you will soon see! Me personally, I rarely if ever want or have a need to know a valve's characteristics, I simply want to quickly know if it has an excellent chance of working in an item of equipment, and I have owned a Mullard for over forty years. So that's my recommendation.

[Radio Wrangler]

Different valve testers have different combinations of sockets, so, first decide which types of valves you are going to test so that you can choose a machine which they will actually fit! Older type sockets got dropped from later testers.

The AVO ones are about the most comprehensive and are rather good. But, and it's a big but, the audiophiles and guitar people have latched onto them. They are seen as profit making machines by valve-sellers on auction sites. "AVO tested" boosts the prices they can get. Consequently the prices of these machines is forced sky high. All the people on here with one got it before the frenzy started.

Taylor made some quite good ones, though they are less comprehensive in the types they can test (fewer sockets, fewer connection combinations) They're not cheap, but have been passed by by the cultists, so they are a lot more affordable.

THe Mullard 'High speed' tester was the mainstay of radio and TV shops. It isn't a mutual conductance tester like the AVO and Taylor machines, but they did their job. You might suspect Mullard knew a thing or two about valves. You might also suspect they wanted to sell new valves ;-) But the Mullard tester is card programmed. You can only test things you have the right card for.

If you want a tester that knocks the spots off an AVO, build one! look on here for the thread on the Sussex valve tester and sit back for a long read. Brilliant for testing valves, measuring characteristics, etc, but useless for boosting valve prices on ebay.

David

[GMB]

I have to admit that I hardly ever use a valve tester. If I was running a shop that sold valves I would do, but otherwise the question that you need to have answered is "Does this valve work in the circuit it is in?". Best found by measuring what is going on in the circuit because most circuits are not making use of every last scrap of performance as a rule.

Apart from some over-worked power valves developing leakage, I usually find that valves are by far the most reliable part of any circuit. Maybe this is because the contents are entirely sealed from the external environment.

[M0FYA Andy]

Surely one very good reason for wanting a valve tester is exactly the same as for wanting to own all the obsolete equipment we spend hours discussing on here - because it's fun!
None of it is 'needed', it is owned purely for enjoyment.

Andy

[Argus25]

One of the problems with contemplating any test equipment is the "fish bowl effect". You decide you want a Goldfish, you get a couple in a small bowl, after a while you realize how hopelessly limited it is for you and the fish, so you buy a small aquarium, get a few more fish & some pumps & filters. Before long its crowded out and the filters are overloaded, so you get a bigger and bigger aquarium with more expensive and bigger pumps and filters and lamps. Each time, money is lost that you never recover. Financial analysis shows that you would have been much better off to go for a good one in the first place and avoid the upgrade pathway.

Likewise, why get a cheap run of the mill valve tester with a good -bad pass fail meter.
One way is to just splash out, spend more than you ever imagined and go straight for a really good tester the first time. That way you will never sell it or need to upgrade it and it will last you a lifetime.

I would recommend the Hickok TV-10. It reads out Transconductance directly with a very accurate meter scale. It is a piece of cake to check and/or adjust its calibration. It has a paper scroll inside it that goes from here to China with nearly every American valve-test settings, so no separate data manual is needed. For some early UK made valves you can use adapters. They are made so well likely it will never need repairs. One like this is a good example:

https://www.ebay.com/itm/TV-10A-U-Mu...Ydx3:rk:1:pf:0

The prices of these have gone up drastically over the last decade as folks have realized their benefits over other types of testers. When I got mine 15 years ago it was only $150. But in ten years, their price will probably double again, so its still a good investment.

[David Simpson]

Hello Millay,
If you check the Forum's "SEARCH" facility, you'll see that this very same question has been raised several times in recent months & exhaustively answered. If you decide on one particular valve tester, then use "SEARCH" to uncover heaps of very helpful ownership info that has arisen over many years.
If you are into valve circuitry design or building audio amplifiers, for example - then you'll need a tester which reads Ia & Gm. If you're just into ordinary radio repairs, then one of the "red/white/green zone" (bad/ maybe ok/ good) meter indication testers is all you need. If you're reasonably confident in building radio/electronic things - build your own tester to suit your particular needs. You'll save yourself a wad of cash considering the inflated speculative internet prices for known makes, particularly AVO.

Regards, David

[ParcGwyn]

Have you thought of making your own, I published a simple design here: https://www.instructables.com/id/SIm...e-Tube-Tester/ that works quite well for me.

Dave

GW7ONS

[Argus25]

One advantage of a professionally made transconductance tester, like a TV-10, is you have multiple tube sockets & switches required with the switch settings right in front of you for the valve under test (marked on the data scroll) and there is far less chance of making an error with the connections (as they are all done for you) or the voltages applied to the particular valve's terminals being incorrect, for example destroying the heater or heater cathode insulation.

In addition, on the data scroll, right there with the correct switch settings, is the acceptable range of transconductance for the valve under test, which has already been determined for you.

If you go down a simple home made tester route, all these conveniences are missing and the chance of accidents in valve testing can be increased and the interpretation of results more varied.

[Bazz4CQJ]

Another way to approach this question is to ask, "What's actually for sale?"
Starting out with a look on ebay, the answer is "not very much!". If it's true that £100 might get something, then at the high end, you'd be looking at ballpark prices of around £1200.

Pretty much all of the testers which were commercially produced are quite old now and some replacement parts can be very hard to find. In terms of getting help to sort out any problems, I'd guess that in the UK, the various Avo testers are the best known and non-UK makes the least well known.

B

[Craig Sawyers]

When valves were not in fashion and every electronics manufacturer went silicon, huge numbers of valve testers went into landfill. I know someone who had collected ten AVO VCM163, and ended up throwing them out during a clear out a couple of decades ago - at that point they had little value, whereas now it is difficult to get one less than £1k.

In fairness if you tried to build a replica of a VCM163 it would cost you much more than £1k.

As has already been mentioned, the Sussex takes quite a lot of beating if you have DIY skills. The other one is the uTracer http://www.dos4ever.com/uTracer3/uTracer3_pag0.html

Craig

[chriswood1900]

There are a couple of other options if you have some basic DIY electronic skills using such as https://www.radioelec.com/en/tube-te...l-352_387.html and available here https://www.ebay.co.uk/itm/VAKUUM-RO...sAAMXQdm5Q-Nf-
Ready built testers just needs a case and choice of sockets etc.
I built one of the computer controlled ones which was shown here https://www.vintage-radio.net/forum/...d.php?t=130919 support via email in English was good the only downside was the software was in French, but the manuals are available in English.
Chris

[PsychMan]

They can be fun and useful tools, unless they are restored however they may themselves become another project to work on.

You don't NEED them, but why not. If it's part of your diagnostic process, fair enough.

Everyone has different ways of approaching problems, Shango066 (of youtube fame) has at times tested capacitors by passing audio through them, used thermal imaging cameras to look for heat spots on a chassis, and other whacky ways. He enjoys what he does, makes fun videos and gets there in the end. It's a hobby after all

[Argus25]

Originally Posted by PsychMan

Shango066 (of youtube fame) has at times tested capacitors by passing audio through them, used thermal imaging cameras to look for heat spots on a chassis, and other whacky ways.

Passing audio through them ?

I always find it interesting and amusing that some people believe that anything (current or energy of any kind) "passes through a capacitor" .

Nothing (unless the capacitor is electrically leaky) passes through a capacitor, no signal, no current, no power transfer, nothing.

In the capacitor the only currents that flow are to and from the plates and accumulated as charges on them. All the currents are in the circuit, external to the capacitor.

Yet, people who use capacitors imagine them as passing an alternating signal from one stage to the next. To the extent that we even name them "coupling capacitors" in a vain attempt to obscure our understanding of the Physics of their operating principles even further.

[Station X]

One post moved to a new thread here:-

https://www.vintage-radio.net/forum/...d.php?t=154209

[PsychMan]

Originally Posted by Argus25

Passing audio through them ?

I always find it interesting and amusing that some people believe that anything (current or energy of any kind) "passes through a capacitor" .

Nothing (unless the capacitor is electrically leaky) passes through a capacitor, no signal, no current, no power transfer, nothing.

In the capacitor the only currents that flow are to and from the plates and accumulated as charges on them. All the currents are in the circuit, external to the capacitor.

Yet, people who use capacitors imagine them as passing an alternating signal from one stage to the next. To the extent that we even name them "coupling capacitors" in a vain attempt to obscure our understanding of the Physics of their operating principles even further.

Slightly pedantic if I may say so . Of course correct, each end is not electrically connected.

They could be perceived as passing an audio signal however if you apply it one side and get a signal at the other, depending on state and value of said capacitor.

Surely when we refer to "coupling capacitors" we mean capacitive coupling, which is correct terminology?

EDIT: My understanding of the physics admittedly isn't very good, and certainly you would know far more than me on matters electrical. I do however hope to better my understanding in both areas

[MrBungle]

I don’t have a lot of valve stuff going through but if I do I just test the heater on a power supply and make sure the getter isn’t white. If it doesn’t work in situ I buy another NOS one and stuff it in. No issues so far. And no expensive tester needed so far! I had one in a VTVM which was marginal but I measured and eliminated all surrounding components and bias with a DMM and that was it.

[Argus25]

Originally Posted by PsychMan

Slightly pedantic if I may say so . Of course correct, each end is not electrically connected.

Surely when we refer to "coupling capacitors" we mean capacitive coupling, which is correct terminology?

Yes correct. Perhaps what I said was an exaggeration to the extent that capacitors also store energy in their electric field and it can be released later. So they can behave as a power storage & transfer device even though the currents are in the circuit external to the capacitor body.