Not sure this is the ideal forum for this, but i am looking for a recommendation on a used tube tester. I have a number of tubes I have collected, many from my father's estate, others from auctions and parts from equipment etc. For the most part, these are older tubes from vintage radio, consoles, TVs etc. Maybe a few early amps as well.
I need a tester that can cover a fair variety of tubes, though I don't expect one to capture 100% of everything. Also not looking to spend hundreds of dollars but I realize even used these testers aren't particularly cheap. I'm not particularly knowledgeable about tubes beyond some I used in my guitar amps years ago (6L6GC, 12ax7 etc., though the bulk of the tubes I have to test really aren't that and are much older (most probably are 50/60's tubes which is when my dad was doing lots of repairs, a few as old as 1930's from radios I've purchased at auctions)
Any recommendations on brand/model testers to look for on Eb*y and what to look out for if purchasing one? Thanks for the expert help here!
Jim.
I need a tester that can cover a fair variety of tubes, though I don't expect one to capture 100% of everything. Also not looking to spend hundreds of dollars but I realize even used these testers aren't particularly cheap. I'm not particularly knowledgeable about tubes beyond some I used in my guitar amps years ago (6L6GC, 12ax7 etc., though the bulk of the tubes I have to test really aren't that and are much older (most probably are 50/60's tubes which is when my dad was doing lots of repairs, a few as old as 1930's from radios I've purchased at auctions)
Any recommendations on brand/model testers to look for on Eb*y and what to look out for if purchasing one? Thanks for the expert help here!
Jim.
Hi Jim,
If you don't want to spend a lot of money on a tester I doubt you'd find
a good working one. Possible but I'm not sure that is realistic.
Reason
I'm guessing they haven't been built in some 30 years. Uncle Sam might
have some in storage still, but they will all need maintence.
AND
Anything good, working and not beat up will probably go for about
a couple hundred USD.
REMEMBER
Everyone who wants or need one isn't going to by junk. The price will be
relatively high. You might get lucky though.
In my case, I bought a B&K 700 Mutual Conductance Tester from a buddy
of mine 20 years ago and it tests a LOT of tubes.
BUT
I still had to rebuild it and recalibrate it a few years ago because it
quit working, this included getting replacement tubes for it, replacing
all the electrolytics in it, changing other parts that drifted, cleaning the
pots etc. Then burning everything in, then calibrating it, then finding
some known tubes that I had writtin down the values to, and adjusted
the tester further.
Anyone who has done this recently is going to let their tester go cheap.
The danger is also, if you test tubes with a screwed up tube tester, then
you might be throwing away a lot of good tubes...or...might be passing
tubes that are damaged not in spec that could ruin prized equipment if
they fail in it.
It happened to me.
My prized quad of tested guaranteed "NOS" tubes popped
and took out my Marantz 8B with it. My "friend" Mr. Gary Dodd,
who sold me the tubes, refused to return my calls...
which was confirmation that it was no mistake.
So don't go cheap with your tester. B&K 700, 707 will test lots of tubes you
want. TVd7-u and others are good, some more limited. Be prepared to
spend some money and you still might need to refurbish it even it it works
today.
What part of the country are you in?
Do you have a list of tubes ?
Have pics?
You might have some good tubes that you can use and
others would be willing to purchase.
Also be aware that a lot of tubes are no longer needed and many
probably will never be used again either, i.e., lots of TV tubes
and some radio tubes are worthless. It will take time to ID the
ones to keep and the ones to not bother with.
If you don't want to fool with the testing, I might be willing to
help for little money and some of the tubes or a selling
arrangement, etc. It just needs to be an arms length transaction.
I could also donate to the cause, I have many TV tubes and others
with a few good ones in the pile too.
PM me if you like. Just be comfortable with whomever it is
you chose to work with. Watch out for the smooth talking
sales man types...if they call you "buddy" walk away.
When I was in the Marines buddy was also used
as a derogatory term. I won't get into that here
either.
Cheers,
If you don't want to spend a lot of money on a tester I doubt you'd find
a good working one. Possible but I'm not sure that is realistic.
Reason
I'm guessing they haven't been built in some 30 years. Uncle Sam might
have some in storage still, but they will all need maintence.
AND
Anything good, working and not beat up will probably go for about
a couple hundred USD.
REMEMBER
Everyone who wants or need one isn't going to by junk. The price will be
relatively high. You might get lucky though.
In my case, I bought a B&K 700 Mutual Conductance Tester from a buddy
of mine 20 years ago and it tests a LOT of tubes.
BUT
I still had to rebuild it and recalibrate it a few years ago because it
quit working, this included getting replacement tubes for it, replacing
all the electrolytics in it, changing other parts that drifted, cleaning the
pots etc. Then burning everything in, then calibrating it, then finding
some known tubes that I had writtin down the values to, and adjusted
the tester further.
Anyone who has done this recently is going to let their tester go cheap.
The danger is also, if you test tubes with a screwed up tube tester, then
you might be throwing away a lot of good tubes...or...might be passing
tubes that are damaged not in spec that could ruin prized equipment if
they fail in it.
It happened to me.
My prized quad of tested guaranteed "NOS" tubes popped
and took out my Marantz 8B with it. My "friend" Mr. Gary Dodd,
who sold me the tubes, refused to return my calls...
which was confirmation that it was no mistake.
So don't go cheap with your tester. B&K 700, 707 will test lots of tubes you
want. TVd7-u and others are good, some more limited. Be prepared to
spend some money and you still might need to refurbish it even it it works
today.
What part of the country are you in?
Do you have a list of tubes ?
Have pics?
You might have some good tubes that you can use and
others would be willing to purchase.
Also be aware that a lot of tubes are no longer needed and many
probably will never be used again either, i.e., lots of TV tubes
and some radio tubes are worthless. It will take time to ID the
ones to keep and the ones to not bother with.
If you don't want to fool with the testing, I might be willing to
help for little money and some of the tubes or a selling
arrangement, etc. It just needs to be an arms length transaction.
I could also donate to the cause, I have many TV tubes and others
with a few good ones in the pile too.
PM me if you like. Just be comfortable with whomever it is
you chose to work with. Watch out for the smooth talking
sales man types...if they call you "buddy" walk away.
When I was in the Marines buddy was also used
as a derogatory term. I won't get into that here
either.
Cheers,
Last edited:
I'm in Maryland. I believe it's well over 200 hundred tubes. I haven't cataloged them yet - just sorted them into various boxes - tubes that start with 2 (e.g. 2letters or 21, 25 etc), start with 3, start with 5, start with 6 (easily 100 of these), start with 12, and some misc tubes that start with something else or can't read the designation.
I'm sure the majority are TV tubes as that is what he mostly worked on.
When I was a child I remember weekly trips to Lafayette to use their tube tester.
Even though I'm sure most are good (he would mark the box if it had one as weak if it was, or put a piece of written tape on it if there wasn't a box and there aren't many I see that way at all ) and I'm sure he threw away a bad one if they were known to be that way, I wasn't comfortable selling any of them without testing them so I could qualify how good they are or not. I may just put the whole lot up on ebay and sell it "as-is" untested, but I'm sure they will have more value if I can prove they are good. It's a balance/gamble of shelling out $200 bucks for a tester to maybe get that or less in the tube value or maybe a lot more.
I could start to catalog these and post here, but if I do, which lot(s) should be the priority?
I'm sure the majority are TV tubes as that is what he mostly worked on.
When I was a child I remember weekly trips to Lafayette to use their tube tester.
Even though I'm sure most are good (he would mark the box if it had one as weak if it was, or put a piece of written tape on it if there wasn't a box and there aren't many I see that way at all ) and I'm sure he threw away a bad one if they were known to be that way, I wasn't comfortable selling any of them without testing them so I could qualify how good they are or not. I may just put the whole lot up on ebay and sell it "as-is" untested, but I'm sure they will have more value if I can prove they are good. It's a balance/gamble of shelling out $200 bucks for a tester to maybe get that or less in the tube value or maybe a lot more.
I could start to catalog these and post here, but if I do, which lot(s) should be the priority?
You won't find a reliable tester for $200. As has been stated above, a good tester will cost a few hundred dollars and it will most likely be a restoration project; a tester ready to use will cost about $500.
Many of the two digit tubes are worth some money e.g., 45. Tubes with four numerical digits e.g., 5881 can be worth money. Tubes that start with 6 or 12 can be worth money. Most of the rest aren't worth much if they are TV tubes.
Before the internet we used the Antique Electric Supply price list to value tubes. It is still a good place to check prices although epay and on line tube vendors will also give you a good prediction of the price.
So, you are on the right track by sorting through them and separating them by type. Then you can start looking up the prices.
Many of the two digit tubes are worth some money e.g., 45. Tubes with four numerical digits e.g., 5881 can be worth money. Tubes that start with 6 or 12 can be worth money. Most of the rest aren't worth much if they are TV tubes.
Before the internet we used the Antique Electric Supply price list to value tubes. It is still a good place to check prices although epay and on line tube vendors will also give you a good prediction of the price.
So, you are on the right track by sorting through them and separating them by type. Then you can start looking up the prices.
You've got a decent collection of low number, and 6 / 12 tubes - quite a few useful for audio, many not worth a lot of cash.
I would probably sell as is, the old emission type testers are truly worthless for anything more than telling that the filaments are good and the tube passes current. A good mutual transconductance tester is going run $500 and up, for example I've seen Hickok 539s go for north of $800..
I would probably sell as is, the old emission type testers are truly worthless for anything more than telling that the filaments are good and the tube passes current. A good mutual transconductance tester is going run $500 and up, for example I've seen Hickok 539s go for north of $800..
Jim,
As Paulustris and Kevin stated.
The Hickocks are great units and they have a
good history of accuracy and reliability. That's
why Kevin has one. He'll use it for all its
capabilities.
If this is a one off thing having that high end
of a tester probably isn't what you need.
The tubes are mostly TV types but about 1/8-14 of
the tubes maybe useful to folks.
5u4
5v4
6au6
6cg7
ccg8
6sn7
6K6
6v6
12Ax7
12At7
12Au7
12by7a
Cant recall about the OD3.
Those are the ones I recognize right off the bat. There other 6s and 12s
I know other folks use for stuff.
I think folks look for the 80 rectifier and the 5y3
Hope that helps.
Wish you had some 6550, KT88, KT77 5881 and 6V6 and
other power tubes.
Have a great week.
As Paulustris and Kevin stated.
The Hickocks are great units and they have a
good history of accuracy and reliability. That's
why Kevin has one. He'll use it for all its
capabilities.
If this is a one off thing having that high end
of a tester probably isn't what you need.
The tubes are mostly TV types but about 1/8-14 of
the tubes maybe useful to folks.
5u4
5v4
6au6
6cg7
ccg8
6sn7
6K6
6v6
12Ax7
12At7
12Au7
12by7a
Cant recall about the OD3.
Those are the ones I recognize right off the bat. There other 6s and 12s
I know other folks use for stuff.
I think folks look for the 80 rectifier and the 5y3
Hope that helps.
Wish you had some 6550, KT88, KT77 5881 and 6V6 and
other power tubes.
Have a great week.
That's pretty much what I expected (though there were a couple of 6v6's in there. I think my path forward is pretty clear - sell it all as a "as-is" lot. Thanks to all that responded on this thread.
Recommendation on how to pack? Given i don't have boxes for most of these. The extreme would be to bubble wrap each one of course, but looking for something a little simpler (yet still safe)
Recommendation on how to pack? Given i don't have boxes for most of these. The extreme would be to bubble wrap each one of course, but looking for something a little simpler (yet still safe)
That's why it's better to make up your own tube tester
It's far simpler than building an amplifier, and it will tell you far more than any "black box" approach tester ever will. Furthermore, a 200-300 dollar set-up will do the same as some very expensive tube testers will. Furthermore the adjustable supplies used in a tube tester are great for powering all kinds of tube projectsRemember that most tubes have their operating characteristics defined in current readings at a certain grid and anode voltage. So just build a test jig that supplies these voltages and you are done. Most tubes are bad if they measure below 60% anode current.
HP/agilent Bench power supplies seem to be cheap in the USA, working/not working you could likely pick up about 2 for under a 100 bucks. your going to need a low voltage unit for the heaters, or a centre tapped heater transformer (if your testing DHT's)If your only testing 6.3 volt tubes a small heater transformer will suffice. And a standard 0-60 volt unit for bias purposes.
Then you need a small industrial control transformer for the high voltage that outputs at least 230 vac bridge rectify, and filter this whit a small choke. And control the primary through a small variac.
Then make yourself a nice panel whit sockets and 4mm Banana connectors to set the pin out of the tubes, add some cheap LED panel meters from china to monitor all important voltages and your done.
A gas test is easily implemented, just insert a 1 Meg restistor in the grid lead of the tube under test, if the tube is gassy, the grid will become more positively biased and the anode current will increase.
Transconductance measurements are really easy to, for this you will need a small oscillator whit a stable amplitude and a digital voltmeter. Just insert a 100mv or 1V test signal onto the grid of the tube and measure the AC voltage over a resistor in the anode lead.
Here is a nice illustration of what I just described. Weston 686 9B Tube Tester - YouTube
That Weston tube analyser is a just a collection of adjustable power supplies and some meters.
There was someone on this forum that made his own transmitting tube tester, I'm having trouble recalling who, but it sure was impressive.
If you need some help, cooking something up, I'd be happy to
+1. Some of the vintage testers were notoriously innacurate anyway.
Here's a popular DIY tester design:
The "Sussex" Homebrew Valve Tester. - UK Vintage Radio Repair and Restoration Discussion Forum
I've boxed up valves by folding corrugated carboard into a triangle, like a Toblerone. You can make an almost un-crushable box that way.
Last edited:
It is worth noting that tube testers were sold because radio servicemen working ion consumer equipment back in the tube days were not, in general, highly trained. In fact, especially before colour TV, quite a few were self taught. A tube tester was not infallible, but it was a good guide. Few had a good oscilloscope.
Back in the tube days, I worked in a company working on profesional electronics, and all of us were fully trained, eg 3-year technical college trained or better. We had an AVO Valve Characteristic Tester - one of the very best tube testers made, and well beyond what an ordinary radio or TV tech could afford or ever see.
But it got hardly any use. Why? Because one can just about always work out what's crook, and what's good, by measuring the voltages around any tube, and reasoning out what possible fault would give the readings obtained. If not, the oscilloscope would reveal what's wrong.
It's worth reading the tube testing section in the famous Radiotron Designer's Handbook. Basically it says:-
a) if it is a power amplifier tube, measure the power output - if good, the tubes good, if not either it of a component is bad. Doesn't matter what a basic tube tester says - unless it is one of the better types that actually measures power output.
b) If it is a voltage amplifier, is it drawing the right current, and not giving distortion?
c) If it is an oscillator, is the grid current correct?
One aspect is not straightforward to check in-circuit is heater/cathode leakage. Excesive leakage may or may not cause hum and various other weird symptoms depending on the circuit. It's the one thing that a tube tester can do well.
But don't forget that bad leakage as measured on a tube tester may not matter in the slightest in-circuit (as in circuits where the cathode is grounded, and circuits where the cathode is grounded via a low value resistor and/or a large capacitor). And why throw out a tube that works just fine?
There is some value in testing emission, as low emission is an indicator of end of life. But note that in most non-power stage circuits, tubes are usually operated well below the manufactuer's designed current. But if it's a voltage amplifer not distorting, it hasn't failed. If you get the rated output power from a power stage, it hasn't failed.
Back in the tube days, I worked in a company working on profesional electronics, and all of us were fully trained, eg 3-year technical college trained or better. We had an AVO Valve Characteristic Tester - one of the very best tube testers made, and well beyond what an ordinary radio or TV tech could afford or ever see.
But it got hardly any use. Why? Because one can just about always work out what's crook, and what's good, by measuring the voltages around any tube, and reasoning out what possible fault would give the readings obtained. If not, the oscilloscope would reveal what's wrong.
It's worth reading the tube testing section in the famous Radiotron Designer's Handbook. Basically it says:-
a) if it is a power amplifier tube, measure the power output - if good, the tubes good, if not either it of a component is bad. Doesn't matter what a basic tube tester says - unless it is one of the better types that actually measures power output.
b) If it is a voltage amplifier, is it drawing the right current, and not giving distortion?
c) If it is an oscillator, is the grid current correct?
One aspect is not straightforward to check in-circuit is heater/cathode leakage. Excesive leakage may or may not cause hum and various other weird symptoms depending on the circuit. It's the one thing that a tube tester can do well.
But don't forget that bad leakage as measured on a tube tester may not matter in the slightest in-circuit (as in circuits where the cathode is grounded, and circuits where the cathode is grounded via a low value resistor and/or a large capacitor). And why throw out a tube that works just fine?
There is some value in testing emission, as low emission is an indicator of end of life. But note that in most non-power stage circuits, tubes are usually operated well below the manufactuer's designed current. But if it's a voltage amplifer not distorting, it hasn't failed. If you get the rated output power from a power stage, it hasn't failed.
Last edited:
Yes, you have seen the exact one I have and I payed $1200, in fact I believe mine was compared side by side to yours to see how accurate it is. The mercury type 83 crapped out so I replaced it and the 5Y3 along with a couple of minor adjustment/repairs. Not gonna lie for a minute I got worried, I thought the transformer was crapping out on me after I spoke with Roger Kennedy but it was just the 83 rectifier tube. I would say all in all it is still worth the money I payed and have been happy to give it a good home.
Moral of the story a good tester will cost you some $$$$$. I would say at least $500 if you are serious, and there is always a DIY tube tester which was mentioned. For me having an old Hickok 539 is a piece of history and if anything should go up in value.
I was gong to say you Brits know all the tricks...
Then the guy from down under chimed in...
So, it is you UKers know all the tricks?
Then I was going to write this,
What's the name of that special park y'all had there
in England? That won the II war for us by cracking
the Enigma, and the Enigma on steroids.
Bletchley Park.
And went back to read who had the AVO tester...
You Netherlands are a good lot...
Keit, if you find another non used AVO tester,
please PM me I could use one.
...from the other side of the pond's from all y'all.
Cheers,
Then the guy from down under chimed in...
So, it is you UKers know all the tricks?
Then I was going to write this,
What's the name of that special park y'all had there
in England? That won the II war for us by cracking
the Enigma, and the Enigma on steroids.
Bletchley Park.
And went back to read who had the AVO tester...
You Netherlands are a good lot...
Keit, if you find another non used AVO tester,
please PM me I could use one.
...from the other side of the pond's from all y'all.
Cheers,
Eh?
SyncTronX, you've got buckley's. If I ever (if ever...) find an un-used AVO Valve Characteristic Meter, I'm seizing it, and I'm keeping it. Not so much because its one of the best, but because it's like old copies of the British techie magazine Wireless World (of which I have an almost complete set) - it has gone up in value in recent years, and will go up still more. And unlike Wireless World, nobody can scan an AVO tester onto a DVD.
SyncTronX, you've got buckley's. If I ever (if ever...) find an un-used AVO Valve Characteristic Meter, I'm seizing it, and I'm keeping it. Not so much because its one of the best, but because it's like old copies of the British techie magazine Wireless World (of which I have an almost complete set) - it has gone up in value in recent years, and will go up still more. And unlike Wireless World, nobody can scan an AVO tester onto a DVD.
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.