Valve testing

[MrPunch]

I have inherited 100s of radio (mostly) valves, maybe 1,000 in all!
I'm in the process of selling and I had thought of investing in a tester but from the research I've done, it seems I'd need more than one tester and a bit of knowledge too!
People on here have given me good advice in the past, so if anyone has any thoughts ......

[GrimJosef]

My gut feeling is that any valve which would sell, tested, for two or three pounds or less isn't worth spending the time testing. In that price range, provided the getter hasn't gone white, the heater shows electrical continuity and there are no unexpected cold pin-to-pin shorts, most people who want one are prepared to take a punt at much the same price on untested ones.

If the valve would be worth a fiver tested then it is (just about) worth spending the time testing it. You'd need to have lots in that price bracket though before it was worth, from an economic point of view, investing in a tester.

Just my two penn'orth of course.

Cheers,

GJ

[PortugalTV]

Just group them in bundles (miniature radio valves, tv valves, amplifier output valves, old valves (30's 40's)) and sell them untested...
most valves are cheap new old stock so like others said buying a tester just for that is not a good solution...most "bad" tubes test fine on a regular emission tester and most tubes that test weak on said tester still perform OK. Best test is substitution so people like to buy bundles of tubes just to have 3 or 4 of the types they might need.
i have hundreds of unknown condition unboxed tubes that i buy on several ebay auctions...usually i grab them for an average of 0,50€ each and 90% are good. when i see a large bundle for cheap i grab it... when i need ONE specific tube that i dont have i just buy it new old stock just to avoid headache, even if it costs 10€ or so its better than chasing ghosts, but if i have 4 or 5 used tubes and none of them solves my problem then i am confident that the tube is not the problem..

[David Simpson]

Trouble is, Mr Punch, Valve Testers can cost between a couple of hundred quid(An AVO 2Panel, or cheapo Taylor) - to £500 to £1000 for a decent AVO VCM. If you check through "Search" you'll find a mass of info on the merits & costs of all the valve testers used by Forum folk.
Even boxes containing several hundred valves of mixed age & condition might not even get anywhere near £100 to £200 for the lot. ( See em536716's thread post in the "For Sale" forum sub-section back on 25th Jan.).
The condition of large hoards from some old boy's loft or shed often depend on the valve collecting attitude of the hoarder. In the pre & post-war years many folk used to put removed suspect valves back into the box that the new valve came in - these are called "pulls" & are often useless. Due to the austerity learnt during wartime conditions many folk continued this practice well into the 80's. A "Magpie" syndrome, so to speak. Hence hundreds of cheapo bog standard B7G & B9A TV valves often pop up at junk sales & auctions & clear-outs. Hardly worth anything.
If your hoard contains dozens & dozens of TT22's, PX25's, KT88's,(super dooper O/P valves) etc. then they'll need properly testing before you could fairly offer them up for sale. Then maybe, just maybe, it would be worth buying a decent AVO MK3 or 4, or CT160.
Another option would be to chat up a friendly valve tester owning Forum member near you, and see if he might kindly help you.

Regards, David

[Silicon]

If you understand how valves work you can make a simple valve tester from a HT supply, a Multimeter, a valve socket and a few resistors.

The HT supply can come from a healthy valve radio.

You will need an electronic calculator to convert voltage readings to current, and then use that information to calculate the mutual conductance.

It is slow but it can be done. However there are safety issues, especially for novices.

I did this last week because I wanted to check the accuracy of my valve tester.

[snowman_al]

This subject crops up regularly. Maybe it should be a 'sticky'?

Here is a recent one, it suggests grouping the valves into base types and or Series types E, P, U etc. and so forth. https://www.vintage-radio.net/forum/...t=valve+tester

Have a read through and you will see the ones that have the value.

You could list a few or post pictures for the forum to give advice on?
Alan

[MrPunch]

Thanks for the help.
The link was very useful.
I'll try to sort a few and pop 'em onto ebay