Do you have any test equipment in your lab that uses vacuum tubes?

[MarkL]

I have two pieces of test equipment that has vacuum tubes:  A Heathkit IT-28 capacitor checker, and a Spellman 15kV @ 4mA HV supply.  The Spellman has an interesting set of gas voltage regulator tubes in addition to the usual drivers and rectifier tubes.  I've posted photos of it before:

  https://www.eevblog.com/forum/chat/how-many-psu_s-do-you-have/msg393637/#msg393637

I'm still looking for a model ID or schematics if anyone recognizes it.

I also have a tube-powered (5514/811A) Tesla coil which is physically in my lab, but it's not really a piece of test equipment.  It probably has no business being in there given the other sensitive electronics.

Judging from the photos you posted if those metal 6L6's are original I place that supply earlier than 1960. Perhaps early to mid 1950's. It does appear that the tube on the far right....probably a 5U4....has at some point been replaced. If original it would have had a glass envelope just like your 0A3 VR tubes.

Sharp eye!  Yes, I had to replace the shattered 5U4 tube when I first got the unit, so I don't know what the original envelope looked like.  It was an attractive target, sticking out on the corner like that.  Alas, the replacement 5U4 eventually died a natural death since that photo was taken and has since been re-replaced with a diode bridge equivalent.

All the other tubes are original except the two HV rectifiers inside the plastic case, at least as when purchased by me.  The HV rectifiers were not performing well.  The unit still works perfectly.

I'd believe 1950's.  Odd that there's not a trace of a model number.  Only "Spellman" on the meter faces.  Maybe it was a custom unit for someone.  I saw a similar one on ebay many years ago, but mounted in a small metal rack case with a flip-up lid to get to the tubes.

[Martin.M]

that is fine, yes 

But:

Set it to 12 Volts or 15 Volts to feed any small transistor experiment,
Then press STANDBY and look what the voltage output will do before shutting down finally..  (a typical 30V Transistor will be RIP )
Heathkit made a bullshit there, it may be better to remove "Standby" and type there "WORST CASE SWITCH"

That may be true but that supply is poor choice for that application and is not meant for 12-15V equipment.

Of coarse, but when they build a unit from zero to 400, that have to work.
OFF is OFF and not enhancing to +60V before OFF, = Bullshit 
Standby with a Heathkit is simply, you remove the + Plug, then it`s trustful OFF.

Martin

[Martin.M]

 



the nice american Set.
The glouchester version is different, they are VVM, not VTVM 

[MaxFrister]

I have a couple.

[med6753]

I have two pieces of test equipment that has vacuum tubes:  A Heathkit IT-28 capacitor checker, and a Spellman 15kV @ 4mA HV supply.  The Spellman has an interesting set of gas voltage regulator tubes in addition to the usual drivers and rectifier tubes.  I've posted photos of it before:

  https://www.eevblog.com/forum/chat/how-many-psu_s-do-you-have/msg393637/#msg393637

I'm still looking for a model ID or schematics if anyone recognizes it.

I also have a tube-powered (5514/811A) Tesla coil which is physically in my lab, but it's not really a piece of test equipment.  It probably has no business being in there given the other sensitive electronics.

Judging from the photos you posted if those metal 6L6's are original I place that supply earlier than 1960. Perhaps early to mid 1950's. It does appear that the tube on the far right....probably a 5U4....has at some point been replaced. If original it would have had a glass envelope just like your 0A3 VR tubes.

Sharp eye!  Yes, I had to replace the shattered 5U4 tube when I first got the unit, so I don't know what the original envelope looked like.  It was an attractive target, sticking out on the corner like that.  Alas, the replacement 5U4 eventually died a natural death since that photo was taken and has since been re-replaced with a diode bridge equivalent.

All the other tubes are original except the two HV rectifiers inside the plastic case, at least as when purchased by me.  The HV rectifiers were not performing well.  The unit still works perfectly.

I'd believe 1950's.  Odd that there's not a trace of a model number.  Only "Spellman" on the meter faces.  Maybe it was a custom unit for someone.  I saw a similar one on ebay many years ago, but mounted in a small metal rack case with a flip-up lid to get to the tubes.

Are the HV rectifiers 1B3's by chance? From what I can see it appears so.

[Martin.M]

hello Max,
that`s very nice,
but the 564 have a pair of dual differential amplifiers in the slots, there is no time base.
Martin

[MaxFrister]

Most of these have been restored and working, but not these 2 scopes.  Note the red tags. 

[med6753]

(Attachment Link)

the nice american Set.
The glouchester version is different, they are VVM, not VTVM 

Yep, my American Heath V-7A VTVM has a British meter courtesy of a fellow blogger in the UK. The original American meter had damaged bearings.

[schmitt trigger]

something glowing, yes.

(Attachment Link)

Many moons ago, I worked in a company whihc had a few of the Tek instruments you are showing here. I know they are VERY HEAVY.

And from the photo, it looks like your lab is located in the attic.

I hope you did not break your back carrying all that stuff up the stairs. 

[EE-digger]

Mostly in good working condition except for the Dumont:

RCA WV98C VoltOhmyst VTVM
Dumont / Fairchild 401 scope
Fluke 412B High voltage supply
HP 400FL ac voltmeter
HP 401 oscillator (tube or FET??)


But alas, none have been used in years 

[vk6zgo]

 I often wonder why HP call the 410C an "Electronic Voltmeter", as it can read Resistance & Current as well.
Still, I suppose other "VTVMs" can do similar things.

Now, this is a "Vacuum Tube Voltmeter"!
https://www.ietlabs.com/pdf/Manuals/GR/726-A%20Vacumm%20Tube%20VM.pdf
It was "AC voltages only"----How does that probe grab you?

I had one for years, until, in a misguided "Nice guy" moment, I donated it to an Electronics Museum.
They had a wonderful assortment of stuff, so I wasn't worried that it wasn't yet displayed.

Years went by, & the decision was made by the "powers that be" to dedicate the museum to the early spark radio equipment used by the coastal radio station that originally occupied the site.
To this end, all the other stuff was "cleared out".

Where to? -----Dunno, maybe landfill!

[med6753]

I often wonder why HP call the 410C an "Electronic Voltmeter", as it can read Resistance & Current as well.
Still, I suppose other "VTVMs" can do similar things.

Now, this is a "Vacuum Tube Voltmeter"!
https://www.ietlabs.com/pdf/Manuals/GR/726-A%20Vacumm%20Tube%20VM.pdf
It was "AC voltages only"----How does that probe grab you?

I had one for years, until, in a misguided "Nice guy" moment, I donated it to an Electronics Museum.
They had a wonderful assortment of stuff, so I wasn't worried that it wasn't yet displayed.

Years went by, & the decision was made by the "powers that be" to dedicate the museum to the early spark radio equipment used by the coastal radio station that originally occupied the site.
To this end, all the other stuff was "cleared out".

Where to? -----Dunno, maybe landfill!

Powered vacuum tube probes were quite common in the 1950's. Today's equivalent is an FET probe.

[vk6zgo]

I often wonder why HP call the 410C an "Electronic Voltmeter", as it can read Resistance & Current as well.
Still, I suppose other "VTVMs" can do similar things.

Now, this is a "Vacuum Tube Voltmeter"!
https://www.ietlabs.com/pdf/Manuals/GR/726-A%20Vacumm%20Tube%20VM.pdf
It was "AC voltages only"----How does that probe grab you?

I had one for years, until, in a misguided "Nice guy" moment, I donated it to an Electronics Museum.
They had a wonderful assortment of stuff, so I wasn't worried that it wasn't yet displayed.

Years went by, & the decision was made by the "powers that be" to dedicate the museum to the early spark radio equipment used by the coastal radio station that originally occupied the site.
To this end, all the other stuff was "cleared out".

Where to? -----Dunno, maybe landfill!

Powered vacuum tube probes were quite common in the 1950's. Today's equivalent is an FET probe.

Certainly!----The 410C has one, but the tube in their probe was a lot smaller than the full sized "lighthouse" tube in the 726A probe!
The large probe was always a problem when looking at 1950s/60s Electronics.

The only time I really found the 726A useful was for aligning AM radios (used in conjunction with my portable one valve "signal generator").
It would have been better, though, if it had a DC range, as I could have looked at the receiver AGC instead of audio out.

It did look really cool, though!

[ferdieCX]

When I was student in the 70's, we used a 726A VTVM in the lab at the technical university.
It still is in our warehouse, waiting to be restored.

[vk6zgo]

I always had a bit of a "soft spot" for General Radio equipment.

At 6WF/WN in Perth, in the "Speech input room" at the Tx site, we had GR Audio generators, when I first worked there.
They had a "mechanical digital" frequency display--- when you turned the frequency control, plastic pieces with numbers on them clicked into place behind a viewing window, where they were illuminated from the rear.
It was quite different from the ordinary "rolling" mechanical display used on hour meters & the like.

i ran into quite a lot of GR stuff over the years, but most of it was more esoteric stuff, which spent more time packed in beautiful polished wooden boxes than ever being used!

[schmitt trigger]

General Radio products  were truly the Rolls-Royces of test equipment for many decades.

Not only they had very high performance, but they were beautifully crafted products.

And the mechanical bits and pieces on the inside were simply awesome.

[MarkL]

I have two pieces of test equipment that has vacuum tubes:  A Heathkit IT-28 capacitor checker, and a Spellman 15kV @ 4mA HV supply.  The Spellman has an interesting set of gas voltage regulator tubes in addition to the usual drivers and rectifier tubes.  I've posted photos of it before:

  https://www.eevblog.com/forum/chat/how-many-psu_s-do-you-have/msg393637/#msg393637

I'm still looking for a model ID or schematics if anyone recognizes it.

I also have a tube-powered (5514/811A) Tesla coil which is physically in my lab, but it's not really a piece of test equipment.  It probably has no business being in there given the other sensitive electronics.

Judging from the photos you posted if those metal 6L6's are original I place that supply earlier than 1960. Perhaps early to mid 1950's. It does appear that the tube on the far right....probably a 5U4....has at some point been replaced. If original it would have had a glass envelope just like your 0A3 VR tubes.

Sharp eye!  Yes, I had to replace the shattered 5U4 tube when I first got the unit, so I don't know what the original envelope looked like.  It was an attractive target, sticking out on the corner like that.  Alas, the replacement 5U4 eventually died a natural death since that photo was taken and has since been re-replaced with a diode bridge equivalent.

All the other tubes are original except the two HV rectifiers inside the plastic case, at least as when purchased by me.  The HV rectifiers were not performing well.  The unit still works perfectly.

I'd believe 1950's.  Odd that there's not a trace of a model number.  Only "Spellman" on the meter faces.  Maybe it was a custom unit for someone.  I saw a similar one on ebay many years ago, but mounted in a small metal rack case with a flip-up lid to get to the tubes.

Are the HV rectifiers 1B3's by chance? From what I can see it appears so.

Close - They're 1G3.

I guess they needed more plate current than the 1B3.  Difficult to tell them apart by looking at the internal structure.  1G3 is a sub for 1B3.

[med6753]

Close - They're 1G3.

I guess they needed more plate current than the 1B3.  Difficult to tell them apart by looking at the internal structure.  1G3 is a sub for 1B3.

According to the RCA Receiving Tube Manual 1G3/1B3 are identical....no difference in characteristics.

[xrunner]

Um ... just a CRT scope - Agilent 54622D mixed signal scope. 

[Addicted2AnalogTek]

I'm only a minor player in the tube gear world.  I've got a few old Tek cal fixtures:

(2) Type 106 square wave generators
067-0502-01 amplitude calibrator
Type 191 constant amplitude sine wave gen
067-0532-01 constant amplitude sine wave gen
067-0532-00 constant amplitude sine wave gen (in pieces)

This of course excludes all of the CRTs

[MarkL]

Close - They're 1G3.

I guess they needed more plate current than the 1B3.  Difficult to tell them apart by looking at the internal structure.  1G3 is a sub for 1B3.

According to the RCA Receiving Tube Manual 1G3/1B3 are identical....no difference in characteristics.

Interesting.  I was looking here:

  http://tubedata.milbert.com/sheets14.html

Some of the data sheets do show them to have the same ratings.  Some don't.

I also have a copy of the RCA Receiving Tube Manual.  One thing that's different is that the 1G3 has a slightly smaller height (3+9/16" vs. 4+1/16").

My sub book shows 1G3 as a sub for 1B3, but not the other way around.

[n5al]

Apart from CRTs and VFDs, none of my test equipment uses vacuum tubes.  I have a HF linear amplifier that uses 3-500 tubes, but that's not test equipment, of course.

[zitt]

Hikok 605A Tube Tester - missing main needle meter.



I'd like to get this tester working so I can resurrect my Grandma's AM Radio from 1930s which is also a vacuum tubes.

[Martin.M]

A triple nickel is on my wants list.  Even more beautiful with the P11 phosphor! 

hello Pat,
look for a P7 dual coating screen, they have a fast blue and a slowly greenyellow, so when the dot is slowly running its blue and draws a grennyellow line.
That is the most cute CRT Tek have build. P7 is very useful for slowly frequencys about the very long delay of the greenyellow. In fast actions it looks blue only.
The delay time of the greenyellow will reach 2 seconds, the blue have only ms

Martin

Picture = Triple Nickel, P7
the second picture is a 551 Dual Beam,with options  P11 and 12kV mod (= another graticules glass, with a text below)

[Cubdriver]

Beautiful scopes, Martin - you have an awesome collection of them!  I'm keeping my eyes open, but I fear like many of the heavy old Tek iron that they're getting more and more rare as audiophools gut them for their dual triodes and discard the carcasses.  That really burns me up!

Keep up your preservation efforts!!

-Pat

Edit to add - thanks for the tip on the P7 dual phosphor - I'd read about it, but never gave it much thought - it looks like a great combination!