Building a tube matcher

[selloutrr]

i'm not sure what good those computer tube testers are. not to be a frown but here is why.. and it's not french you could probably get a hottie at a college to translate.. wait these are looking really good!

The curve tracer still requires you to find a way to interface with it. if it's intended to be used with the other tester, your top voltage is +280? I don't see a power transformer to power the tubes so where is that voltage coming from? another thing to buy? The LCD screen is meaningless because it doesn't give you a test reference so all you have to go on is what it tells you so what does a good tube actually test at?
then we can start to talk about stability and accurancy.

you can build your own lab grade tube tester with all external test equipment, meters, power supplies, etc. a designated tester in a box is not the only way.

[Phil_S]

My poor command of French suggests something like this. It works with your computer via USB interface. It tests at "working" voltages, up to 28mA @ 80v and 12mA@ 250V. There is also something about testing tetrodes and pentodes in pesudo triode mode, whatever that is. It's got 2 voltage regulation pots.

Given the gaps in my comprehension of French, I'm not all that reliable here. However, I think the gist of it is that it doesn't do high voltage the way we want it to. We want something that will put a couple of hundred volts on the screen and more on the plate. I don't think this thing will do that. Basically, I think it is a trode tester, and probably decent for doing what it's built for. It's not for power tubes.

For only $599 you can get a Maxi-matcher.
http://www.maximatcher.com/maximatcher.html
There is no free lunch. Nice thought, though.

If you really want to know and there's no one else, I can hunker down and try for a good translation. They don't teach us all the tech-speak in school and it's been 40 years or more since I studied French.

[rp]

Build yourself a modest fixed bias amp with a bias pot in it.

Or, you can build this thing, add a couple DPDT switches, and OT, a preamp tube and a pot and when it's not testing tubes it s a 100W Champ. I am kidding!

[FYL]

i'm not sure what good those computer tube testers are.

Really good.

The curve tracer still requires you to find a way to interface with it.

Serial connection to a Wintel box, or USB with an adapter.

if it's intended to be used with the other tester, your top voltage is +280?

They are diffrent testers. The tracer is for bench apps and can test all kind of tubes, including power bottles at up to 430V in stock form, the tester is designed for field apps - hamfests, etc.

I don't see a power transformer to power the tubes so where is that voltage coming from?

The tracer needs HV, 24V and heaters external AC supplies; the tester uses board-mounted DC to DC converters and can work on batteries.

another thing to buy?

These boards are engines, you need to add all of the glue etc. depending on your application.

Here's an implementation of the tracer: http://www.youtube.com/watch?v=LmoEAIUshAE

[selloutrr]

said and done after you add the glue you are in it how much?

still not sure how accurate it is?

I'm sorry cheap tube testers bother me, I expect alot out of them and trusting them to be accurate is on the top of my list.

how bad would you feel if you had vintage tubes that you threw out because your tester was havig a bad day...? ouch Or the flip side of that you purchase NOS tubes that are tested on a questionable tester as good and in fact are bad/perform poorly...? not cool!

It was not cheap to get the amplitrex fully up and running, though It did work right out of the box in stand alone mode. I went ahead and hooked it up to a dedicated computer, with laser printer and brother label printer. Powered with a constant voltage transformer to regulate and smooth the power to make the testing even more accurate. It's over kill, but I have ZERO doubt of a tubes performance when tested, so that is worth the piece of mind. Plus its pretty cool to be able to hand the client documentation of their tubes results, esp if the tube needs to be replaced. It's also great for matching tubes in a batch I can save the data for each tube and the software can help make matched sets as well as full control over all presets and test functions. so you can do as little or as much testing as you want or need.

I really think it's above and beyond for most applications, if you are concerned about power tubes. Get a maxi matcher they are build solid, they work great! and hold a very nice return on investment. The company is more then happy to answer any questions and stand by the products they build. I do suggest you buy socket savers from maxi matcher to prevent unwanted wear and tear when you insert and remove tubes to keep the sockets from wearing out. then if you find you want to test preamp tubes buy a VTV vacume tube valley small character tester for about $1200(includes power supply and adaptor card). You can't curve trace but you can listen for microphonics. The VTV, or if you can find one, the George Kaye, are what most of the Tube Depot's use to test preamp tubes. Sovtek/ Electro Harmonix made a tube tester/ curver tracer called Sophia that was a patch style tester, very accurate, but no longer in production and hard to find. There are several companies taking old hickok's upping the voltage and adding DOS based computer software. the testers are card testers so as long as you have a card for that tube you can test it. the limitations being you are stuck with what you have. though a solid tester in the right application. I'm not sure if you can print the results or not?

ok sorry for the ramble. hope it helped.

[FYL]

said and done after you add the glue you are in it how much?

Typically $350 or so. Not a lot for a fully fledged curve tracer and tube tester.

still not sure how accurate it is?

Good enough for any application: ± 5% worst case, worst spec for current is 0.5 mA ±1 bit on the 256 mA scale. Heck, this is a 10-bit engine on a sub $100 board...

It was not cheap to get the amplitrex fully up and running, though It did work right out of the box in stand alone mode.

The Amplitrex AT1000 is a really fine piece of hardware + software at $2,500+.

Get a maxi matcher they are build solid, they work great! and hold a very nice return on investment.

Also a really fine piece of stuff at $600 or so. Alas options are somewhat overpriced: $35 for a single octal socket saver? My cost is $12 for a quartet...

then if you find you want to test preamp tubes buy a VTV vacume tube valley small character tester for about $1200(includes power supply and adaptor card).

Then we'll disagree: the VTV is overhyped & overpriced. Check the Tube IMP if you're looking for a ready to use basic small tube tester.

[img:641:481]http://www.tube-imp.co.uk/tube-tester-m ... mphome.jpg[/img]

http://www.tube-imp.co.uk/

you can listen for microphonics.

My bench testing amp - a basic SE amp with noval and octal sockets on an open Hammond chassis - allows me to do the same in real world conditions. $150 worth of parts...

Sovtek/ Electro Harmonix made a tube tester/ curver tracer called Sophia that was a patch style tester, very accurate, but no longer in production and hard to find.

[img:590:507]http://www.audiomatica.com/img/sofia.jpg[/img]

Sofia was manufactured by Audiomatica in Italy. It was a very nice tester, simple but fully featured - 3x channels with 16-bit DAC's for instance. It was withdrawn from the market because it didn't meet European (and presumably American) safety standards.

[Structo]

Man, $615 for the Imp.

[selloutrr]

i will agree with the VTV being over priced but the TUbe IMP is still $615 and limited to 9 pin tubes without the built in ability to listen to the microphones. so you still need to buy / build a listening station. there is something to be said for the small all enclosed design. the VTV sell used on ebay for $700-800.

I wish the amplitrex was only $2500. lol I live in california so I got hit with sales tax. buy the time you get it hooked up for full on testing it's over $4K

socket saver are socket savers just suggesting you use them to prevent wear and tear that can be avoided. It's alot easier to get a new socket saver then having to rewire a test socket in a tester. what i like about the ones maximatcher sells is that they bolt down to the chassis preventing them from coming out of the test socket.

[selloutrr]

the TUBe IMP has a great tube test link for DIY
http://www.tube-imp.co.uk/

[Structo]

I was looking at tube testers on ebay last night and bid on 5 of them.
They are going for crazy money now.

I wasn't going to pay over $100 including shipping so maybe I'm too much of a cheapskate.

I think that tester on the first page, the Price tester would work.

But it would cost over $100 easily.
Ideally you would use a Variac with it to control your plate voltage but I don't have one of those either so that would be an added expense.
Actually the only test gear I have at the moment is my DVM.

I would eventually like to get a scope, sig gen, cap tester, etc.

I did find a freeware scope app for my PC, but I haven't tried it yet.

Kind of afraid to hook up the probe to my sound card and have it get fried by me doing something wrong.

You are supposed to make the probe out of shielded cable, put a cap in series with it to block DC.

http://www.electronics-lab.com/download ... index.html

There seems to be quite a few freeware apps for signal generation and O'scopes.

[Prairie Dawg]

I was looking at tube testers on ebay last night and bid on 5 of them.
They are going for crazy money now.

I wasn't going to pay over $100 including shipping so maybe I'm too much of a cheapskate.

I think that tester on the first page, the Price tester would work.

But it would cost over $100 easily.
Ideally you would use a Variac with it to control your plate voltage but I don't have one of those either so that would be an added expense.
Actually the only test gear I have at the moment is my DVM.

I would eventually like to get a scope, sig gen, cap tester, etc.

I did find a freeware scope app for my PC, but I haven't tried it yet.

Kind of afraid to hook up the probe to my sound card and have it get fried by me doing something wrong.

You are supposed to make the probe out of shielded cable, put a cap in series with it to block DC.

http://www.electronics-lab.com/download ... index.html

There seems to be quite a few freeware apps for signal generation and O'scopes.

Using a variac to change plate voltage with a tube tester would not be helpful because you would be changing all the voltages.

[Structo]

You would only use the variac on the B+ transformer.
The heater supply is a separate 6.3vac transformer.

[Prairie Dawg]

You would only use the variac on the B+ transformer.
The heater supply is a separate 6.3vac transformer.

Not so on my Hickok. One transformer provides filament voltages from 1.1 to 117vac-that is it's primary function. The same transformer also provides plate voltage and bias voltage.

Using a variac would raise all the voltages or lower them all.

[Structo]

I was talking about the home built tester not the Hickok.

[jcr1234]

Basically, what I want to do is be able to bias tubes, I can do that with a bias probe or Webers Bias Rite or a similar device. Ok, That I get, but I would also like to be able to test how much life is left in a pulled tube so I know it wont die on me 10 minutes after I get it home.

Is there one device (under $500) that will do both of these things? Or, am I going to have to get a Hickok and have it calibrated and also get a bias probe.

Thanks in advance guys, you're awesome.

Oh and btw, this doesnt have to be lab-accurate, Im just a nerd who likes messing around with stuff for my fun.