Oldschool tubes

Can you not take the photo in daylight? Could barely make out the outline of the tester.

I assume it is a go/no-go style, and perhaps verifies if the filaments are good. Can't imagine it doing much else...

Of course, one can tell if the filaments are good if the tube warms up in the set, so if that is all it is then it is an early audio-phool tool.

John

A common as dirt filament tester. They were common as dirt, and sold for about $3 in the early '60s. They hyped as real tube testers.

"It Does What It Says on the Tin"

Just like the cans of 'Replacement Vacuum'?

How do I get the vacuum out of the can and back in the tube, though?

That was explained on the tin, not in the ads.

Tube testers came as

Filament test

Emission (basically see some plate current)

Gas (grid current)

Shorts

"Mutual conductance" with real AC signals

There were transistor testers for a while, but they went away.

--

John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  

jlarkin att highlandtechnology dott com 
http://www.highlandtechnology.com

I don't feel much like buying an old-timey tube tester, I don't havea lot of space in the lab, they're bulky and I wouldn't usually have much use for it - tubes are kinda cool but I'm not an obsessive and don't do much with them usually.

I can check for shorts with a DMM, for emission and mutual conductance I can probably just put 'em in a socket and wire up the standard CC circuit in the datasheet, using one of the variable high voltage boost converter modules I have on hand, feed with signal generator and see what happens

Actually for emission it would probably be easiest to wire them as common plate with the plate directly to a HV supply and rig up a bench supply as a constant current cathode load and sweep the current

John Larkin wrote on 11/9/2017 8:44 PM:

There are transistor testers on many voltmeters. A six (or maybe more, I don't have one here to look at) pin socket lets you plug in a transistor of any configuration (EBC, BEC, etc) and I think the gain is shown. But I have never used that feature, so I'm not sure I'm remembering it right.

--

Rick C 

Viewed the eclipse at Wintercrest Farms, 
on the centerline of totality since 1998

Shorts don't always show up until you load the tube (or tap it). You can also get leakage and other odd things (microphonics, etc.) that the better tube testers would show. Yes you can make some test gear in your shop, but how do you get a standard unless you have several NOS tubes to compare to? We do repair tube gear and so have to have a couple of tube testers in our shop - mutual conductance is our preferred machine.

As our work is on arcade games and jukeboxes from the first to the most recent we have test gear going back to the 40s right up to current. Everything from armature growlers, Fluke 9010s w/8 & 16 pit pods, PROM/EPROM programmers from 1702s up to 8mb devices (so far), Hard drive duplicator, injection molder, 3D printer, dynamic RAM tester (4116s and friends), and on and on.

At least it is fun to go to work!

John

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** I still do a lot of work with valves (tubes if you are a Yank) but have never thought buying a "Tube Tester" worthwhile. They simply do not carry out tests needed for audio service or production.

The best way to test a tube is to into plug it into a known working piece o f gear and put it through it paces. Another way is to replace a suspect tub e with a known good one and see if that changes things.

Recently, inspired by the schem of an old AVO163 "Valve Characteristic Mete r" I designed and built my own tube tester that would perform all the neede d tests at least as far as common 8 and 9 pin output tubes were concerned.

Using a very simple circuit plus basic bench equipment, it puts a power tub e under realistic operating conditions and finds if it working normally. Al so matching the performance and idle bias settings for sets of tubes to be used in parallel is easily accommodated. The beauty of the method used is t he tube operates under low duty cycle conditions so plate and screen dissip ation limits are not approached or exceeded.

I find most use for the tester is with newly purchased tubes, to see if the y are up to spec or not.

MY colleague, Rod Elliot, published the design on his web sight as Project

165 in February last year.

The many warnings are justified, valve testers can destroy valves.

.... Phil

I think I want a AVO VCM163 Valve Characteristic Meter!

John ;-#)#

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an

r

to

e

ave never thought buying a "Tube Tester" worthwhile. They simply do not ca rry out tests needed for audio service or production.

ce of gear and put it through it paces. Another way is to replace a suspect tube with a known good one and see if that changes things.

Meter" I designed and built my own tube tester that would perform all the n eeded tests at least as far as common 8 and 9 pin output tubes were concern ed.

tube under realistic operating conditions and finds if it working normally . Also matching the performance and idle bias settings for sets of tubes to be used in parallel is easily accommodated. The beauty of the method used is the tube operates under low duty cycle conditions so plate and screen di ssipation limits are not approached or exceeded.

they are up to spec or not.

ect 165 in February last year.

** That is a very ambiguous thing to post.

My design does a whole HOST of things the AVO does NOT - since it is specif ically an output tube tester with used defined parameters that one to mimic or exceed actual operation.

The only similarity lies in the use of unrectified AC for screen and plate voltages.

..... Phil

Yes, Phil, it was ambiguous, however we use about forty or more different types of tubes. And your process above, while it would be great on high end equipment, is deeper than we would ever need to go for our jukebox customers. These aren't Macintosh amps - and my staff just can't take the time to learn a whole new set of testing procedures just to get the best tube for the job. On the other hand, for the audiophile who wants the best, your procedure could be useful for them I suspect - and they would likely be willing to take the time to assemble the gear to accomplish it. I need something quicker and easier to use in our shop. Hence the MC style tube tester which does a pretty good test for most tubes. And when the results are inconclusive we have swapped tubes from our stock to try and find the best sounding ones. Pretty subjective at that point, eh?

The AVO looked like a step up from our current 1950s tester...

John :-#)#

I like that idea. Did you have to wear a space-suit in case any vacuum got spilled?

Mike.

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can

our

s to

ube

have never thought buying a "Tube Tester" worthwhile. They simply do not carry out tests needed for audio service or production.

iece of gear and put it through it paces. Another way is to replace a suspe ct tube with a known good one and see if that changes things.

c Meter" I designed and built my own tube tester that would perform all the needed tests at least as far as common 8 and 9 pin output tubes were conce rned.

er tube under realistic operating conditions and finds if it working normal ly.. Also matching the performance and idle bias settings for sets of tubes to be used in parallel is easily accommodated. The beauty of the method us ed is the tube operates under low duty cycle conditions so plate and screen dissipation limits are not approached or exceeded.

if they are up to spec or not.

oject 165 in February last year.

ecifically an output tube tester with used defined parameters that one to m imic or exceed actual operation.

ate voltages.

** Not power tubes you don't.

** My customers all own guitar amps, some of them ancient.

So the same need you seem to have.

** Not my quest either.

I just need to sort duds out of batches of new or used tubes when I do not have the target amp on hand.

** Takes the same time as any tube tester, 60 seconds for the filament to h eat and another 60 for the various checks.

** Best sounding?? You on drugs?

** If you can find one, it will likely cost you an arm and a leg. And do nothing very useful.

.... Phil

o:

rs.

complementary XKCD comic about vacuum:

also careful about WHERE vacuum is:

Bye Jack

I still want my Acme Portable Hole.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC / Hobbs ElectroOptics 
Optics, Electro-optics, Photonics, Analog Electronics 
Briarcliff Manor NY 10510 

http://electrooptical.net 
https://hobbs-eo.com