tube curve tracer

[w4bfs]

Reed W2CQH suggested looking into obtaining a curve tracer for tube testing.  I am sure that most everyone is familiar with the conventional wisdom that was stated similar to this:  'tube testers are ok for a starting point but the only valid test for a tube is to substitute in a known good tube'

this is all well and good but the rub is the 'known good tube' .... just a few tubes are in current production and even new-old-stock tubes may have allowed air in leakage and are therefore gassy (I checked my 6BA7 stash and found 3 NOS gassy tubes)
whats a ham to do ?

there is a reasonable correlation between transconductance and 'goodness' but only to a certain point and this is typified by a power tube that works to a portion of full power but then runs into gain compression nearing maximum and is found to be emission limited .... hence looking at curve tracing

since curve tracing is duty cycle limited but still can test to full power capability, this seems to be of interest to tube enthusiasts ....  does anyone in the forum have experience to share and suggestions about building a tube curve tracer

[WBear2GCR]

Pretty easy for tubes up to about the size of a 6V6 and maybe a bit beyond.

There's an excellent tube tracer available that does this job from a guy in Europe, my brain says "RonaldDOS4ever" is his "handle"... if no one finds it, I can dig out the info. It's computer controlled and dumps the info into computer files and out onto the display - very neat. ( I should buy one! )

Also Tek made a tube curve tracer.

One CAN take a standard transistor curve tracer and "amp it up" with things like outboard PS, booster amp for the drive, and scaling for the output return (which of course is higher voltage/current than the typical curve tracer can handle).

Outboard scopes can be part of a homebrew curve tracer to give the visual indication

But for most ham stuff, it's pretty much go/no go, and empirical testing in the rig.

I know some folks have built up test chassis for certain tubes. Steve, W2TRH has one for 813 tubes, and I have been meaning to bring mine over. But this is a static tester, not a curve tracer, and output is on a meter.

That's my take...

                    _-_-

[WA4WAX]

Tek made the 576.  Watch it in action on a pair of 6L6GC.

https://www.youtube.com/watch?v=1jKtciKeWUU

[w4bfs]

Tek made the 576.  Watch it in action on a pair of 6L6GC.

https://www.youtube.com/watch?v=1jKtciKeWUU

a nicely done video even if for a business

the Tek 576 is interesting but pricey .......

[W4AMV]

See

http://n4trb.com/AmateurRadio/GE_HamNews/Sideband_Handbook/Sideband_Handbook_09.pdf

Pretty nice, complete and straightforward.

Alan

[w4bfs]

tnx Alan ....looks interesting

tnx Rick W8KHK for making a Tek 575 curve tracer available ... got the unit and accurately described .... will spend some time researching mods ... have found and ordered Alan Douglass's book on vintage test equipment .... looks good

n.b. 3 Nov '15  found some material in Electric Radio issues - 212 p.23 & 213 p. 15 will look into and report

[w4bfs]

n.b. 3 Nov '15  found some material in Electric Radio issues - 212 p.23 & 213 p. 15 will look into and report

there is also the parent article in ER 210 p.11

just skimmed these and these articles were written in 2006 when TV-7 toob testers were still reasonably priced .... that certainly is not the case now ($500 - 700) so drilling and blasting a TV-7 is not-so-good idea

I like to repurpose old gear but I try not to drill new holes in case it should need to be returned to original ....this is to avoid being condemned to radio hell

[RolandSWL]

Not nearly as many knobs to turn:

http://www.dos4ever.com/uTracer3/uTracer3_pag1.html

RSWL...................

[pa0ast]

The micro tracer experience,
Bought this kit  last week from ronald Dekker an IC designer , after reading the message here above . Everyting was in the kit exept solder and tools.  After 2 evenings of soldering and testing it worked really perfect.  You build a part and test it,  again a part and test it with the own on board processor ,   and again , till its ready. Follow the manual , not all values printed on the pcb are correct if You build the 400V version..
  0 - 400V   anode voltage  and 0 - 500 mA current , o - 400 V for g2  or positive G1 ! for transmitting tubes . -40 to 0 V for  G1  .  All parameters measured in a pulsed 1 milisecond puls mode , so no overloading of the tube.  I sell my AVO mk4 tube tester new it has no sense to keep it.
Only a small thing was that you need a RS232 to USB converter that works. The one with 5 V pulses was OK the one with 3,3V not.
Much , much better than other tube testers. ( Also much cheaper )
Anton

[Opcom]

If you buy a 576, you best see that the CRT is good, or be a CRT expert.

[WBear2GCR]

The micro tracer experience,
Bought this kit  last week from ronald Dekker an IC designer , after reading the message here above . Everyting was in the kit exept solder and tools.  After 2 evenings of soldering and testing it worked really perfect.  You build a part and test it,  again a part and test it with the own on board processor ,   and again , till its ready. Follow the manual , not all values printed on the pcb are correct if You build the 400V version..
  0 - 400V   anode voltage  and 0 - 500 mA current , o - 400 V for g2  or positive G1 ! for transmitting tubes . -40 to 0 V for  G1  .  All parameters measured in a pulsed 1 milisecond puls mode , so no overloading of the tube.  I sell my AVO mk4 tube tester new it has no sense to keep it.
Only a small thing was that you need a RS232 to USB converter that works. The one with 5 V pulses was OK the one with 3,3V not.
Much , much better than other tube testers. ( Also much cheaper )
Anton

Guess this is the latest version... he's been at it for some years now, more or less kicking and complaining along the way as to how he really did not want to actually develop this past the initial phase. But I guess the beast took on a life of its own.

What's the "biggest" sort of tube that the present version will handle??

And, what did you use for the hardware for the sockets/pin selection??

How long did ti take to build, and is there any surface mount in it?

And, what's he charging for this??

                    _-_-

[pa0ast]

On this moment i can measure a RV12P35 , 6KD6 , 4D32 and that kind of tubes. Max is 400V anode voltage and 500mA of current. Also the572B /811 etc.
Still busy with the hardware. On this moment  making a drawer for the interconnection wires on the front/ bottom .
there are 6 connectors to the front   F, F, C, G1, G2, A. and 9 above those 6  with the pinning of the tube sockets. So i can choose every pinning i need. The kit took me 2 evenings to build and test,  and install the software. The kit came with a book like the ones from heathkit , a step by step assembly and test manual with schematics etc..
Only two smd parts are used on the pcb but these where premounted already on the pcb. And i payed 215 Euro , thats around 250 dollar inc postage.
picture 2 is the box with the tubesockets . picture 1  the working PCB with a tube connected before it was fixed  in the box.
Have fun with it. Anton

[KD6VXI]

This might find its way inside my heathkit tube tester chassis.

Didn't do all the tubes I wanted it to,  and needs a recap,  cord,  etc.  Otherwise in good shape.

Hmmm

--Shane
KD6VXI

[Mike/W8BAC]

I Wonder...

If someone was to design and build a tube tracer equal to a Micro Tracer using vacuum tube technology and state of the art electronics available in 1960, what would the schematic look like? How many tubes would it take to equal the transistors in the Micro Tracer chips and connected computer? To equal the Micro Tracer computer software needed to sense and translate voltage and current amplitude and preform the reams of math needed for a graphic user interface might take an office building full of programmers, key punch operators and loaders. How physically large would the vacuum tube computer be? Ultimately, how much would it cost?

Fun to think about. The equations and graphs printed in the better tube data books show what the "Known Good Tube" should look like. I like the Micro Tracer concept. Your tester socket and patch cord panel looks like fun AJ. I would try this myself if I had a deep need for the nuances of tube traces. A calibrated Hickok 752, VTVM and calculator will have to do.

73
Mike

.